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Ground-level ozone (O 3) pollution is a major air quality issue in densely populated urban areas. Despite a significant decline in human activities in the megacity Shanghai from March 28 to May 31, 2022, ground-level measurements indicate a rise in maximum daily average 8-h (MDA8) O 3 concentrations in comparison to the corresponding period in 2021. There is a need for quantitative analysis to identify the reasons behind this increasing O 3 concentration. We analyzed ground measurements of O 3 and its precursors and meteorological parameters made in Shanghai, using random-forest (RF) model and chemical box model to elucidate the roles of meteorological and chemical factors in influencing O 3 concentrations. Across urban, suburban, semi-rural, and coastal sites, the urban center of Shanghai experienced the largest decreases in the concentrations of nitrogen oxides (NO x ; 53%) and volatile organic compounds (VOCs; 52%), with the most notable rise in MDA8 O 3 concentrations (16%). RF modeling indicates that meteorological factors reduced MDA8 O 3 concentrations by a marginal 3%, whereas a decline in anthropogenic emissions resulted in a 17% increase in MDA8 O 3 concentrations. Chemical box modeling at the Pudong urban site indicates that while the decline in VOCs reduced O 3 production by 42%, this was negated by a reduction in NO x from traffic emissions, which enhanced O 3 production by 51%, resulting in an increase in O 3 production overall. Despite a halving in precursor levels, Shanghai's urban centre remains predominately under VOC-limited conditions throughout the study period, with high NO 2 levels from the petrochemical industry and traffic emissions. Joint control of anthropogenic VOCs (AVOCs) and NO x , with a ratio greater than 1.29, could help avoid exacerbation of O 3 pollution and reduce NO 2 pollution. Our findings emphasize the necessity of reducing industrial emissions along with ongoing green transportation strategies for alleviating O 3 pollution in megacities like Shanghai. • Emission reductions drove an O 3 increase in Shanghai during the 2022 lockdown. • Shanghai's urban centre remains predominately under VOC-limited conditions. • The high NO 2 level was attributed to petrochemical industry and traffic emissions. [ABSTRACT FROM AUTHOR]

Although many previous studies have found that the mitotic arrest deficient 2‐like 1 (MAD2L1) protein contributes to the proliferation of colorectal cancer (CRC) cells, but the upstream mechanism of MAD2L1 is still largely elusive. This study aimed to explore the microRNAs (miRNAs) upstream of MAD2L1 to improve our understanding of the mechanism of the MAD2L1 gene in CRC. The upstream target miRNAs (miR‐515‐5p) of MAD2L1 were predicted by the online databases miRWalk, miRDIP, and TargetScan. Quantitative real‐time PCR (qRT‐PCR) was used to detect the expression level of miR‐515‐5p in human CRC tissues. The targeting relationship between miR‐515‐5p and MAD2L1 was tested by dual luciferase reporter gene assays. The effects of miR‐515‐5p on the biological behaviors of CRC cells by regulating MAD2L1 expression were verified by qRT‐PCR, western blot, Cell Counting Kit‐8, and flow cytometry. The results showed that miR‐515‐5p was a highly reliable upstream miRNA of the MAD2L1 gene. As an upstream target miRNA of MAD2L1, miR‐515‐5p was lowly expression in CRC tissues. The overexpression of miR‐515‐5p could inhibit the proliferation of CRC cells and induce cell cycle arrest at the G1 phase leading to cell apoptosis. However, MAD2L1 gene overexpression could reverse the effects of miR‐515‐5p overexpression on the biological behaviors of CRC cells above. This study illustrated that miR‐515‐5p can inhibit proliferation and induce G1 phase arrest leading to apoptosis in CRC cells. The mechanism underlying this phenomenon may be related to the negative targeted regulation of MAD2L1. [ABSTRACT FROM AUTHOR]

Abstract A two-year gaseous elementary mercury (GEM) measurement was implemented at an iron–steel plant in Yangtze River Delta, China, which provided an excellent opportunity to investigate their dynamic cycling. The hourly GEM concentrations ranged between 0.78 and 113.8 ng m−3, with a mean value of 3.83 ± 2.53 ng m−3. Temporally, seasonal GEM contents decreased as winter ≈ spring > summer > autumn, while diurnal cycling was observed with a steady decrease at 14:00–17:00. GEM variations were found to be related to source emissions, meteorology and regional transportation. Three major oxidants (O 3 , Br and OH radicals) were used to evaluate GEM oxidation in the daytime, and the estimated GEM depletion rate was 70.8 ± 52.5 molecule cm−3 s−1 (0.09 ± 0.06 ng m−3 h−1). The GEM oxidized by Br radicals accounted for 83.4% of the total GEM oxidation rate, followed by O 3 (13.8%). The estimated atmospheric lifetime of GEM was 22.9 to 345.2 days, which implies a major contribution of Br radicals to the GEM sink. These findings highlight the ability of iron–steel industry emissions and in–situ oxidation to affect daily local GEM cycling significantly. Graphical abstract Simplified mechanisms of GEM oxidization by atmospheric oxidant radicals in the iron-steel industry. Unlabelled Image Highlights • A two-year-time hourly measurement of gaseous elemental mercury was implemented in an iron-steel plant in China. • The observed hourly GEM concentrations ranged between 0.78 to 113.8 ng m-3, with a mean value of 3.83 ± 2.53 ng m-3. • The GEM oxidation rate initiated by three major oxidants (O 3 , Br· and OH· radicals) were evaluated. • The calculated GEM lifetime against oxidation ranged from 22.9 to 345.2 days. [ABSTRACT FROM AUTHOR]

A Tethered balloon-based field campaign was launched for the vertical observation of air pollutants within the lower troposphere of 1000 m for the first time over a Chinese megacity, Shanghai in December of 2013. A custom-designed instrumentation platform for tethered balloon observation and ground-based observation synchronously operated for the measurement of same meteorological parameters and typical air pollutants. One episodic event (December 13) was selected with specific focus on particulate black carbon, a short-lived climate forcer with strong warming effect. Diurnal variation of the mixing layer height showed very shallow boundary of less than 300 m in early morning and night due to nocturnal inversion while extended boundary of more than 1000 m from noon to afternoon. Wind profiles showed relatively stagnant synoptic condition in the morning, frequent shifts between upward and downward motion at noon and in the afternoon, and dominant downward motion with sea breeze in the evening. Characteristics of black carbon vertical profiles during four different periods of a day were analyzed and compared. In the morning, surface BC concentration averaged as high as 20 μg/m 3 due to intense traffic emissions from the morning rush hours and unfavorable meteorological conditions. A strong gradient of BC concentrations with altitude was observed from the ground to the top of boundary layer at around 250–370 m. BC gradients turned much smaller above the boundary layer. BC profiles measured during noon and afternoon were the least dependent on heights. The largely extended boundary layer with strong vertical convection was responsible for a well mixing of BC particles in the whole measured column. BC profiles were similar between the early-evening and late-evening phases. The lower troposphere was divided into two stratified air layers with contrasted BC vertical distributions. Profiles at night showed strong gradients from the relatively high surface concentrations to low concentrations near the top of the boundary layer around 200 m. Above the boundary layer, BC increased with altitudes and reached a maximum at the top of 1000 m. Prevailing sea breeze within the boundary layer was mainly responsible for the quick cleanup of BC in the lower altitudes. In contrast, continental outflow via regional transport was the major cause of the enhanced BC aloft. This study provides a first insight of the black carbon vertical profiles over Eastern China, which will have significant implications for narrowing the gaps between the source emissions and observations as well as improving estimations of BC radiative forcing and regional climate. [ABSTRACT FROM AUTHOR]

The coronavirus (COVID-19) pandemic is disrupting the world from many aspects. In this study, the impact of emission variations on PM 2.5 -bound elemental species and health risks associated to inhalation exposure has been analyzed based on real-time measurements at a remote coastal site in Shanghai during the pandemic. Most trace elemental species decreased significantly and displayed almost no diel peaks during the lockdown. After the lockdown, they rebounded rapidly, of which V and Ni even exceeded the levels before the lockdown, suggesting the recovery of both inland and shipping activities. Five sources were identified based on receptor modeling. Coal combustion accounted for more than 70% of the measured elemental concentrations before and during the lockdown. Shipping emissions, fugitive/mineral dust, and waste incineration all showed elevated contributions after the lockdown. The total non-carcinogenic risk (HQ) for the target elements exceeded the risk threshold for both children and adults with chloride as the predominant species contributing to HQ. Whereas, the total carcinogenic risk (TR) for adults was above the acceptable level and much higher than that for children. Waste incineration was the largest contributor to HQ, while manufacture processing and coal combustion were the main sources of TR. Lockdown control measures were beneficial for lowering the carcinogenic risk while unexpectedly increased the non-carcinogenic risk. From the perspective of health effects, priorities of control measures should be given to waste incineration, manufacture processing, and coal combustion. A balanced way should be reached between both lowering the levels of air pollutants and their health risks. [Display omitted]. [ABSTRACT FROM AUTHOR]

The heaviest aerosol pollution day in the historical record of the Yangtze River Delta occurred on 19 January 2007, in which the daily concentration of PM10 reached 512μgm−3 in Shanghai, 463μgm−3 in Suzhou, 354μgm−3 in Hangzhou, and 282μgm−3 in Nanjing. The hourly concentrations of PM2.5 and PM10 reached peak values of 466 and 744μgm−3, respectively, in Shanghai. With visibility <0.6km, the regional haze covered nearly the entire Yangtze River Delta. High ratios of PM2.5/PM10 (61%), SO2/PM10 (0.38) and NO2/PM10 (0.24) were observed. The unusual stagnant dispersion conditions before a cold front played the predominant role in this high pollution episode, with relative humidity (RH) of 88%, both surface and upper-level inversions, as well as low wind speed (<1ms−1). The sulfur oxidation rate (SOR) reached 0.67 and the nitrogen oxidation rate (NOR) reached 0.61, signifying that formation of sulfate and nitrate contributed significantly to the high secondary aerosol concentration of PM2.5. The enrichment factors of As, Cd, and Pb reached 4058, 6971, and 3972, which were 4.45–6.68 times higher than those on good/moderate days. It was demonstrated that emissions from anthropogenic sources, especially stationary sources such as power plants, industrial boilers, and furnaces, were the major contributors to the heaviest aerosol pollution in the delta. More attention should be paid to the increases in emissions and the higher occurrence of haze days that have accompanied the rapid development of the economy in the Yangtze River Delta. [Copyright &y& Elsevier]

Chemical transport models (CTMs) are widely used for air pollution modeling, which suffer from significant biases due to uncertainties in simplified parameterization, meteorological fields, and emission inventories. Accurate diagnosis of simulation biases is critical for the improvement of models, interpretation of results, and management of air quality, especially for the simulation of fine particulate matter (PM 2.5). In this study, an efficient method with high speed and a low computational resource requirement based on the tree-based machine learning (ML) method, the light gradient boosting machine (LightGBM), was designed to diagnose CTM simulation biases. The drivers of the Community Multiscale Air Quality (CMAQ) model biases are compared to observations obtained by simulating PM 2.5 concentrations from the perspectives of meteorology, chemical composition, and emission sources. The source-oriented CMAQ was used to diagnose the influences of different emission sources on PM 2.5 biases. The model can capture the complex relationship between input variables and simulation bias well; meteorology, PM 2.5 components, and source sectors can partially explain the simulation bias. The CMAQ model underestimates PM 2.5 by - 19.25 to - 2.66 µgm-3 in 2019, especially in winter and spring and during high-PM 2.5 events. Secondary organic components showed the largest contribution to the PM 2.5 simulation bias for different regions and seasons (13.8 %–22.6 %) of all components. Relative humidity, cloud cover, and soil surface moisture were the main meteorological factors contributing to PM 2.5 bias in the North China Plain, Pearl River Delta, and northwestern China, respectively. Primary and secondary inorganic components from residential sources showed the two largest contributions to this bias (12.05 % and 12.78 %), implying large uncertainties in this sector. The ML-based methods provide valuable complements to traditional-mechanism-based methods for model improvement, with high efficiency and low reliance on prior information. [ABSTRACT FROM AUTHOR]

In order to explore the mechanism of haze formation, the meteorological effect and chemical reaction process of the explosive growth (EG) of PM2.5 were studied. In this study, the level of PM2.5, water-soluble inorganic ions, carbonaceous aerosols, gaseous precursors, and meteorological factors were analyzed in Shanghai in 2018. The EG event is defined by a net increase of PM2.5 mass concentration greater than or equal to 100 μg m−3 within 3, 6, or 9 h. The results showed that the annual average PM2.5 concentration in Shanghai in 2018 was 43.2 μg m−3, and secondary inorganic aerosols and organic matter (OM) accounted for 55.8% and 20.1% of PM2.5, respectively. The increase and decrease in the contributions of sulfate, nitrate, ammonium (SNA), and elemental carbon (EC) to PM2.5 from clean days to EG, respectively, indicated a strong, secondary transformation during EG. Three EG episodes (Ep) were studied in detail, and the PM2.5 concentration in Ep3 was highest (135.7 μg m−3), followed by Ep2 (129.6 μg m−3), and Ep1 (82.3 μg m−3). The EG was driven by stagnant conditions and chemical reactions (heterogeneous and gas-phase oxidation reactions). This study improves our understanding of the mechanism of haze pollution and provides a scientific basis for air pollution control in Shanghai. [ABSTRACT FROM AUTHOR]

Airborne black carbon is a strong warming component of the atmosphere. Therefore, curbing black carbon emissions should slow down global warming. The 2019 coronavirus pandemic (COVID-19) is a unique opportunity for studying the response of black carbon to the varied human activities, in particular due to lockdown policies. Actually, there is few knowledge on the variations of black carbon in China during lockdowns. Here, we studied the concentrations of particulate matter (PM2.5) and black carbon before, during, and after the lockdown in nine sites of the Yangtze River Delta in Eastern China. Results show 40–60% reduction of PM2.5 and 40–50% reduction of black carbon during the lockdown. The classical bimodal peaks of black carbon in the morning and evening rush hours were highly weakened, indicating the substantial decrease of traffic activities. Contributions from fossil fuels combustion to black carbon decreased about 5–10% during the lockdown. Spatial correlation analysis indicated the clustering of the multi-site black carbon concentrations in the Yangtze River Delta during the lockdown. Overall, control of emissions from traffic and industrial activities should be efficient to curb black carbon levels in the frame of a 'green public transit system' for mega-city clusters such as the Yangtze River Delta. [ABSTRACT FROM AUTHOR]

A cavity attenuated phase shift single scattering albedo monitor was set up on a tethered airship platform to study the vertical profiles of particle light extinction coefficient (b ext) in the lower troposphere (<1000 m) in Shanghai during 12–29 December 2015. Clear transition heights (THs) for vertical profiles of b ext during the polluted days (PM 2.5 > 75 μg m−3) were observed below 1000 m. The vertical differences of b ext were highly dynamic as the vertical variation in b ext was significant by as much as 605 Mm−1. The TH was observed mostly at about 100–200 m, and 450–650 m during night and daytime, respectively, and was in a wide range of ∼50–900 m during 15:00–22:00 due to the low boundary layer and/or the transport of pollutants. In particular, the TH was consistently below 500 m throughout the day during highly polluted haze episodes, highlighting the important role of a stagnant atmosphere situation for high concentrations of PM 2.5. The vertical distribution of b ext did not have a constant rule with respect to relative humidity and wind. Sometimes, peak values of b ext at ∼350 m and 500 m during daytime were caused by enhanced regional transport. During stagnant and highly polluted situations or well-mixed clean days, b ext was usually uniformly distributed below and above the TH, respectively, although b ext was much smaller above the TH. For other situations, local emissions, pollutant transport, and the physical and chemical characteristics of aerosols resulted in highly dynamic vertical profiles of b ext. • The vertical variations of b ext were dynamic within 1000 m. • Transition heights (THs) for b ext were below 1000 m during the polluted days. • b ext was usually uniform below and above the TH during clean and heavy haze episodes. • The TH was consistently below 500 m throughout the day during heavy haze episodes. • Flexible rules were found between b ext and relative humidity/wind within 1000 m. [ABSTRACT FROM AUTHOR]

Background: Colorectal cancer (CRC) ranks as the third most common cancer, accounting for a significant number of cancer-related deaths worldwide every year. Yet, the molecular mechanisms responsible for the progression of this malignancy are not fully understood. Numerous studies indicate that BUB1 mitotic checkpoint serine/threonine kinase B (BUB1B) plays a role in the progression of various malignant tumors. However, the specific biological functions and the detailed mechanisms of how BUB1B influences CRC are still not completely known. This study aimed to explore the expression and role of BUB1B in CRC. Materials and Methods: To achieve this, the expression levels of BUB1B in human CRC tissues and cell lines were examined using real-time polymerase chain reaction and Western blotting. The role and associated mechanisms of BUB1B in CRC cell progression were assessed both in vitro and in vivo using RNA interference. Results: The findings of this study revealed an elevated expression of BUB1B in both CRC tissues and cell lines. The silencing of BUB1B in CRC cell lines notably inhibited cell proliferation, migration, and invasion, leading to cell cycle arrest and apoptosis. In addition, the knockdown of BUB1B inhibited the JNK/c-Jun signaling pathway, increased the expression of proapoptotic proteins, and decreased the expression of antiapoptotic proteins. The effects of BUB1B knockdown on CRC cell progression were reversed by the JNK activator PAF(C-16). Conclusions: In summary, the suppression of BUB1B hindered malignant tumor progression and heightened apoptosis and cell cycle arrest in CRC cells via the JNK/c-Jun pathway. Importantly, the removal of BUB1B expression curtailed tumor growth in human CRC xenografts in nude mice, suggesting its potential as a promising therapeutic target for CRC patients. ClinicalTrials.gov ID: No.2019 K-C086 [ABSTRACT FROM AUTHOR]

The vertical distribution of SO2, NO, NO2, O3, CO, PM2.5, black carbon, particle sizedistribution, species of PM1 within 0-1000m as well as meteorological parameters weremeasured simultaneously on tethered balloon at Wangdu County, Baoding City, NorthChina Plain, as part of the winter field campaign which hold during December2018.During December 18 to 21, the ground monitoring data demonstrated sharp increase of NO,CO and PM2.5 concentration during the nighttime and decrease in the daytime,while the diurnal variation of ozone concentration was the opposite. The increasedconcentrations of pollutants at night mostly due to the much lower boundary layerduring nights, which could be as low as 100 meters. Except for the worse verticaldiffusion at night, the low wind speed also contributed to the increase of pollutantsconcentrations.The organic component accounted for up to 60% of PM2.5 at night, which was the maincontribution to the increased PM2.5. The significant increase of NO, CO and organic may dueto the emission from home heating at night.The vertical detection demonstrated very low boundary layer and inversion layer during theobservation period. The vertical distribution of pollutant in the boundary layer and upper theboundary layer are quite different at night. The concentrations of gaseous pollutants (CO,SO2, NO and NO2) and PM2.5 were higher in the nocturnal boundary layer, and theproportion of organic component, black carbon and chloride were significantly higher thanthat upper the boundary layer. During the daytime, with the development of the boundarylayer, the favorable horizontal and vertical diffusion condition lead to the decreased pollutantsconcentrations. In addition, pollutants with high concentrations were found at high altitudes,where the proportion of secondary components such as nitrates, sulfates and ammoniumwere higher than that of the ground. It may attributed to air mass from regionaltransport. [ABSTRACT FROM AUTHOR]

Since non-methane hydrocarbons (NMHCs) include numerous species of volatile organic compounds (VOCs), they are the only indicators that can characterize the total amount of VOCs in ambient air. More than 90 % of NMHC instruments in the market use the indirect method for NMHC determination, utilizing a gas chromatograph to determine the concentrations of total hydrocarbons (THCs) and methane in air. However, we found indirect NMHC measurements incorrectly characterized the low NMHC concentrations in the urban air. These measurements were hindered by the uncertain changes in the errors associated with low THC concentrations, humidity and macroscopic substances (oxygen) in the atmosphere. In this study, we conducted intercomparisons between 10 instruments in the market using different operation principles; among these, two used the direct method, and eight used the indirect method. For the indirect method, experiments showed that when the NMHC concentration was 50 ppbC , the errors in the measurement results were 32 % (CH4) and 98 % (THC) when compared to theoretical values. The oxygen content in the sample gas directly affected the response of the THC. The effect of increased oxygen content on the analysis of oxygen-containing substances was more significant than that of the increase in hydrocarbon substances. The response of dry zero was blank, and the response value increased non-linearly with relative humidity (RH). RH had a great impact on low NMHC concentrations of nearly 50 %. For the direct method, although various flow designs were applied for different instruments, the results indicated that they generally showed lower interference and higher accuracy for the ambient NMHC measurements. With the online direct methods, we obtained more reliable data and characteristics for low-concentration NMHCs in downtown Shanghai. The median of hourly data was 163.1 ppbC , and the highest ratio of the maximum and minimum concentrations of NMHCs reached 9.56 in a single day. [ABSTRACT FROM AUTHOR]

A tethered balloon-based measurement was conducted to investigate vertical distribution of O 3 over Shanghai, China, during May of 2016. The time-series and diurnal variation of ground-level air pollutants (including O 3 , NO, NO 2 and VOCs) were analyzed systematically. By using TrajStat (a GIS-based software), the potential distant contributions of O 3 might come from East China Sea, and the Yangtze River Delta (YRD). Within 1000 m above ground, the average vertical profiles of O 3 exhibited obviously diurnal characteristics. Most of the NO and O 3 profiles measured on high-ozone days demonstrated anti-correlation. The launches on May 11, 2016 revealed that the Atmospheric Boundary Layer (ABL) and shifting of wind direction contributed to the peaks of O 3 at the upper altitude. A typical case of vertical mixing of O 3 was caught on May 18, 2016, when the ground-level O 3 was greatly influenced by the O 3 transported from high altitude (1500 m above sea level). The present study provides an important insight of the vertical distribution of O 3 over Eastern China, which implied that coupling effects of horizontal and vertical transportations on ground-level ozone should be investigated in future studies. Image 1 • Ozone in rural Shanghai were highly influenced by nearby areas. • Vertical profiles of ozone exhibited obviously diurnal differences. • Vertical mixing of O 3 is an important source of high O 3 in rural Shanghai. [ABSTRACT FROM AUTHOR]

Abstract Fireworks displays are a traditional form of celebration during the Chinese Spring Festival (Festival). In response to the heavy air pollution caused by fireworks, Shanghai, a megacity in China, has imposed regulatory measures on the use of fireworks in recent years. To investigate air quality trends before and after firework regulation was established and quantify its efficiency, gaseous pollutants, PM 2.5 levels, and PM 2.5 chemical composition were synchronously measured at 1 h time intervals at an urban site and a suburban site in Shanghai in the period during and around the Festival from 2013 to 2017. PM 2.5 concentrations at the urban site during the Festival over the five-year period were 79 (max: 524), 94 (290), 53 (163), 50 (146) and 32 (156) μg/m3, respectively, presenting a decreasing trend at a rate of −13.8 μg/m3/yr (p = 0.05). K+ concentrations, which serve as a tracer of fireworks, were 8.2 (max: 159.4), 2.5 (14.6), 2.2 (10.4), 4.3 (44.2) and 0.8 (4.5) μg/m3 during the Festival from 2013 to 2017, respectively, and thus decreased at a rate of −1.3 μg/m3/yr (p = 0.17). Accordingly, fireworks contributed 41 (51.9%), 38 (36.5%), 6 (10.3%), 21 (35.6%), and 4 μg/m3 (12.1%) to PM 2.5 , respectively, implying the effectiveness of firework regulation in Shanghai. Health effects attributed to PM 2.5 pollution in Shanghai during the Festival were assessed based on Poisson regression. The number of premature deaths related to short-term PM 2.5 exposure in Shanghai during the Festival from 2013 to 2017 was 75 (95% CI: 27, 108), 92 (30, 129), 55 (18, 76), 49 (19, 70), and 31 (12, 45), respectively. Daily mortality due to PM 2.5 exposure during the Festival from 2013 to 2017 accounted for 1.4–3.8% of total daily mortality in Shanghai. This study provides scientific evidence of air quality improvement and the effectiveness of firework regulation in Shanghai. Graphical abstract Unlabelled Image Highlights • Significant air quality improvement was observed in Shanghai during the Festival from 2013 to 2017. • Fireworks contributed 41, 38, 6, 21 and 4 μg/m3 to PM 2.5 in Shanghai during the Festival from 2013 to 2017, respectively. • Health effects related to PM 2.5 exposure during the Festival was calculated based on Poisson regression. [ABSTRACT FROM AUTHOR]

Petroleum related emissions are the major anthropogenic sources of volatile organic compounds (VOCs), which served as important precursors for secondary organic aerosol (SOA). However, little is known about the relationship among VOCs emissions from petrochemical industries, SOA formation, and regional PM 2.5 . In this paper, VOCs emitted from a petrochemical industry in Yangtze River Delta (YRD, China) were continuously monitored by an online gas chromatography-photo ionization detector/flame ionization detector (GC-PID/FID) system. Results showed that the total concentration of 68 VOCs species was 151.0 ± 155.6 ppbv, and ethylene, ethane, 2-methylpentane, chloroform, 2,3-dimethyl-butane and propane were the richest species. SOA yield calculated by time-resolved approach was 7.18 ± 10.97 μg m −3 , accounted for 3.35–86.4% of the corresponding PM 2.5 concentration, which was a bit higher than previously reported values. VOCs-sensitiveness (VOCs-S) coefficient was adopted to investigate the quantitative relationship between VOCs and PM 2.5 , found VOCs were more sensitive to PM 2.5 in clean domains than in polluted domains. An exponential function was fitted (y = 3.94x 0.293 – 3.62, r 2  = 0.816) between VOCs-S coefficient versus specific-to-background PM 2.5 ratio for aromatic hydrocarbon. VOCs emitted from petrochemical industry had influence on regional PM 2.5 in this study, and reducing petrochemical emissions might be effective in alleviating haze episodes. [ABSTRACT FROM AUTHOR]

• NO 2 concentrations were 77.3% lower during the closure of WUH. • Steeper reduction in NO than in BTEX levels at SHA. • NO 2 concentrations at WUH were dropped to near zero during airport closure. • Increase in O 3 levels at both WUH and SHA due to reduced NO x emissions. Wuhan Tianhe International Airport (WUH) was suspended to contain the spread of COVID-19, while Shanghai Hongqiao International Airport (SHA) saw a tremendous flight reduction. Closure of a major international airport is extremely rare and thus represents a unique opportunity to straightforwardly observe the impact of airport emissions on local air quality. In this study, a series of statistical tools were applied to analyze the variations in air pollutant levels in the vicinity of WUH and SHA. The results of bivariate polar plots show that airport SHA and WUH are a major source of nitrogen oxides. NO x , NO 2 and NO diminished by 55.8%, 44.1%, 76.9%, and 40.4%, 33.3% and 59.4% during the COVID-19 lockdown compared to those in the same period of 2018 and 2019, under a reduction in aircraft activities by 58.6% and 61.4%. The concentration of NO 2 , SO 2 and PM 2.5 decreased by 77.3%, 8.2%, 29.5%, right after the closure of airport WUH on 23 January 2020. The average concentrations of NO, NO 2 and NO x scatter plots at downwind of SHA after the lockdown were 78.0%, 47.9%, 57.4% and 62.3%, 34.8%, 41.8% lower than those during the same period in 2018 and 2019. However, a significant increase in O 3 levels by 50.0% and 25.9% at WUH and SHA was observed, respectively. These results evidently show decreased nitrogen oxides concentrations in the airport vicinity due to reduced aircraft activities, while amplified O 3 pollution due to a lower titration by NO under strong reduction in NO x emissions. Significantly reduced NO x concentrations and amplified O 3 pollution at the airfield boundary of Shanghai Hongqiao International Airport due to reduced aircraft activities. [Display omitted] [ABSTRACT FROM AUTHOR]

High pollution episodes of PM 2.5 and O 3 were frequently observed at a rural site (N31.0935º, E120.978°) in eastern Yangtze River Delta (YRD) in summer. To study the impacts of photochemical reactions on secondary aerosol formation in this region, we performed real-time measurements of the mass concentration and composition of PM 2.5 , particle size distribution (13.6 ~ 736.5 nm), concentrations of gas pollutants including O 3 , SO 2 , NO 2 , CO, non-methane hydrocarbons (NMHC)), and nitrate radical in 2013. During the sampling period, the average concentration of PM 2.5 was 76.1 (± 16.5) μg/m 3 , in which secondary aerosol species including sulfate, nitrate, ammonium, and secondary organic aerosol (SOA) accounted for ~ 62%. Gas-phase oxidation of SO 2 was mainly responsible for a fast increase of sulfate (at 1.70 μg/m 3 /h) in the morning. Photochemical production of nitric acid was intense during daytime, but particulate nitrate concentration was low in the afternoon due to high temperature. At night, nitrate was mainly formed through the hydrolysis of NO 3 and/or N 2 O 5 . The correlations among NMHC, O x (= O 3 + NO 2 ), and SOA suggested that a combination of high emission of hydrocarbons and active photochemical reactions led to the rapid formation of SOA. In addition, several new particle formation and fast growth events were observed despite high ambient aerosol loading. Since the onset of new particle events was accompanied by a rapid increase of H 2 SO 4 and SOA, enhanced formation of sulfate and SOA driven by photochemical oxidation likely promoted the formation and growth of new particles. Together, our results demonstrated that strong atmospheric photochemical reactions enhanced secondary aerosols formation and led to the synchronous occurrence of high concentrations of PM 2.5 and O 3 in a regional scale. These findings are important for better understanding the air pollution in summer in YRD. [ABSTRACT FROM AUTHOR]

In order to explore the effects of COVID-19 control measures on the concentration and composition of PM2.5-bound polycyclic aromatic hydrocarbons (PAHs), and to better understand the sources of PM2.5-bound PAHs, PM2.5, samples were collected at two sites in urban and suburban areas of Shanghai before the lockdown, during the lockdown, after the lockdown in 2020, and during the same periods in 2019. The mass concentrations of 21 individual PAHs were determined via GC-MS analysis. While the COVID-19 control measures significantly reduced the absolute concentration of PM2.5-bound PAHs, they had no significant effect on their relative abundances, indicating that the significantly reduced traffic emission may not originally be the major source of PAHs in Shanghai. The differences in the composition of PM2.5-bound PAHs at three different lockdown-related periods may be caused by the gas-particle distribution of semi-volatile PAHs. The similarity in the composition of PM2.5-bound PAHs in different functional areas and different periods brings more uncertainties to the identification of PAH sources using the diagnostic ratios. During the lockdown period, the toxic equivalent concentration of PM2.5-bound PAHs in Shanghai was estimated to decrease by about 1/4, which still exhibits substantial carcinogenic risk upon exposure via inhalation. [ABSTRACT FROM AUTHOR]

Organic acids are important aerosol compositions with significant implications on particle formation, growth, acidity, phase state, and environmental impacts. Oxalic acid was found to be the most abundant particulate organic diacid in Shanghai during the study period, accounting for ~58% of the total dicarboxylic acids (C2–C10). Biomass burning (BB) explained a small but non-negligible fraction (less than 10%) of oxalate. Significant correlations between oxalate and sulfate indicated a potentially synergistic formation mechanism of oxalate and sulfate. In addition, meteorological factors such as ambient temperature and relative humidity were found to influence the formation of oxalate. Higher oxalate relative to inorganic particulate content was found in summer. Potential source contribution function analysis suggested that most of the oxalate observed in Shanghai was produced locally. The formation of oxalate was largely impacted by atmospheric oxidation capacity as indicated by its significant correlations with both secondary organic carbon (SOC) and sulfur oxidation ratio (SOR). The evolution of oxalate, oxalate/sulfate, oxalate/organic carbon were consistent with the emission trend of volatile organic carbons (VOCs) in recent years, indicating that oxalate may be derived from secondary oxidation of VOCs, which is further confirmed by a positive relationship between Ox and oxalate/VOCs over the study period. With a detailed characterization of oxalate in Shanghai, our study highlights the importance of regulating primary emissions, such as VOCs, as well as mitigation of atmospheric oxidation capacity in controlling air pollution in a coastal megacity. [ABSTRACT FROM AUTHOR]

Traffic-related air pollution (TRAP) was monitored using a mobile sensor network on 125 urban taxis in Shanghai (November 2019/December 2020), which provide real-time patterns of air pollution at high spatial resolution. Each device determined concentrations of carbon monoxide (CO), nitrogen dioxide (NO2), and PM2.5, which characterised spatial and temporal patterns of on-road pollutants. A total of 80% road coverage (motorways, trunk, primary, and secondary roads) required 80–100 taxis, but only 25 on trunk roads. Higher CO concentrations were observed in the urban centre, NO2 higher in motorway concentrations, and PM2.5 lower in the west away from the city centre. During the COVID-19 lockdown, concentrations of CO, NO2, and PM2.5 in Shanghai decreased by 32, 31 and 41%, compared with the previous period. Local contribution related to traffic emissions changed slightly before and after COVID-19 restrictions, while changing background contributions relate to seasonal variation. Mobile networks are a real-time tool for air quality monitoring, with high spatial resolution (~200 m) and robust against the loss of individual devices. [ABSTRACT FROM AUTHOR]

To ensure good air quality during the China International Import Expo (CIIE) event, stringent emission-reduction measures were implemented in Shanghai. To assess the efficacy of these measures, this study measured typical categories of intermediate/semi volatile organic compounds (I/SVOCs), including alkanes (C 10 –C 26 n-alkanes and pristane), EPA-priority polycyclic aromatic hydrocarbons (PAHs), alkylnaphthalenes, benzothiazole (BTH) and chlorobenzenes (CBs), at an urban site of Shanghai before and during two CIIE events (2019 and 2020; non-CIIE versus CIIE). The average concentrations of alkanes and PAHs during both 2019 and 2020 CIIE events decreased by approximately 41% and 17%, respectively, compared to non-CIIE periods. However, the decline in BTH and CBs was only observed during CIIE-2019. Secondary organic aerosol (SOA) formation from alkanes, PAHs and BTH was evaluated under atmospheric conditions, revealing considerable SOA contributions from dimethylnaphthalenes and BTH. Positive matrix factorization (PMF) analysis further revealed that life-related sources, such as cooking and residential emissions, make a noticeable contribution (21.6%) in addition to the commonly concerned gasoline-vehicle sources (31.5%), diesel-related emissions (20.8%), industrial emissions (18.6%) and ship emissions (7.5%). These findings provide valuable insights into the efficacy of the implemented measures in reducing atmospheric I/SVOCs levels. Moreover, our results highlight the significance of exploring additional individual species of I/SVOCs and life-related sources for further research and policy development. [Display omitted] • Thedrop in atmospheric I/SVOCs observed during CIIE showed the efficacy of the temporarily implemented measures. • Dimethylnaphthalenes and BTH showed considerable potentials as SOA precursors under atmospheric conditions. • Life-related sources of I/SVOCs should be considered for further research and policy design. [ABSTRACT FROM AUTHOR]

Surface ozone (O 3) pollution is an emerging concern in China. Hangzhou Bay (HZB), where the petrochemical industry is clustered, has become one of China's most O 3 polluted areas due to exposure to volatile organic compounds (VOCs) emissions and land-sea breezes. It is urgently need to investigate the multiple drivers of surface O 3 generation in HZB more specifically. The spatial distribution of O 3 trends from April to September (2015–2022) in HZB depicts a general upward trend, with an observed trend of 0.26 μg/m3 a−1, where meteorological factors contribute to 54°% based on the stepwise multiple linear regression (MLR). Ensembled machine learning is more efficient and accurate, especially the Light Gradient Boosting model (LightGBM, R2 = 0.84) outperforms other machine learning algorithms. The Shapley additive explanation (SHAP) technique allows for more in-depth quantification of the contribution of specific factors to O 3 trends. The results of the LightGBM-SHAP algorithm present that solar radiation plays a leading role in O 3 generation. More importantly, stronger solar radiation can still lead to high O 3 concentration accumulation even at lower temperature based on the interaction of SHAP values. For the precursor's emissions, the ratio of formaldehyde-to-NO 2 (HCHO/NO 2) obtained from the Tropospheric Monitoring Instrument (TROPOMI) satellite observations, shows the study area is located in the VOCs-limited and transitional regimes, highlighting that VOCs control is more cost-effective. • Meteorological drivers contribute 54°% to the O 3 increase in HZB. • Stronger solar radiation can lead to high O 3 pollution even at lower temperature. • HZB is in the VOCs-limited and transitional regimes. [ABSTRACT FROM AUTHOR]

• Reductions of PM, NO 2 , SO 2 and CO under lockdown differed in urban agglomerations. • The mitigation of PM2.5 concentrations due to lockdown was considerable. • Although the lockdown did not reverse uptrend of O 3 , it retarded increment of O 3. • BTH, YRD and PRD suffered from more polluted air masses of regional transport. To investigate the air quality change during the COVID-19 pandemic, we analyzed spatiotemporal variations of six criteria pollutants in nine typical urban agglomerations in China using ground-based data and examined meteorological influences through correlation analysis and backward trajectory analysis under different responses. Concentrations of PM 2.5 , PM 10 , NO 2 , SO 2 and CO in urban agglomerations respectively decreased by 18%–45% (30%–62%), 17%–53% (22%–39%), 47%-64% (14%–41%), 9%–34% (0%–53%) and 16%-52% (23%–56%) during Lockdown (Post-lockdown) period relative to Pre-lockdown period. PM 2.5 pollution events occurred during Lockdown in Beijing-Tianjin-Hebe (BTH) and Middle and South Liaoning (MSL), and daily O 3 concentration rose to grade Ⅱ standard in Post-lockdown period. Distinct from the nationwide slump of NO 2 during Lockdown period, a rebound (∼40%) in Post-lockdown period was observed in Cheng-Yu (CY), Yangtze River Middle-Reach (YRMR), Yangtze River Delta (YRD) and Pearl River Delta (PRD). With slightly higher wind speed compared with 2019, the reduction of PM 2.5 (51%–62%) in Post-lockdown period is more than 2019 (15%–46%) in HC (Harbin-Changchun), MSL, BTH, CP (Central Plain) and SP (Shandong-Peninsula), suggesting lockdown measures are effective to PM 2.5 alleviation. Although O 3 concentrations generally increased during the lockdown, its increment rate declined compared with 2019 under similar sunlight duration and temperature. Additionally, unlike HC, MSL and BTH, which suffered from additional (> 30%) air masses from surrounding areas after the lockdown, the polluted air masses reaching YRD and PRD mostly originated from the long-distance transport, highlighting the importance of joint regional governance. [Display omitted] [ABSTRACT FROM AUTHOR]

• The ratio between OH production from HONO and from (HONO+O3) lager than 90% before 12:00. • The source of HONO from combustion emission is ~26%. • NO 2 being converted to HONO under the conditions with high aerosol extinction coefficient and high relative humidity was a dominant factor for the secondary produce of HONO. • HONO mainly distributed near the surface and localized, and NO 2 mainly transmitted from north at ~ 0.6 km. Ground-based multi-axis differential optical absorption spectroscopy (MAX-DOAS) observations were operated from 02 to 21 December 2018 in Leshan, southwest China, to measure HONO, NO 2 and aerosol extinction vertical distributions, and these were the first MAX-DOAS measurement results in Sichuan Basin. During the measurement period, characteristic ranges for surface concentration were found to be 0.26–4.58 km−1 and averaged at 0.93 km−1 for aerosol extinction, 0.49 to 35.2 ppb and averaged at 4.57 ppb for NO 2 and 0.03 to 7.38 ppb and averaged at 1.05 ppb for HONO. Moreover, vertical profiles of aerosol, NO 2 and HONO were retrieved from MAX-DOAS measurements using the Heidelberg Profile (HEIPRO) algorithm. By analysing the vertical gradients of pollutants and meteorological information, we found that aerosol and HONO are strongly localised, while NO 2 is mainly transmitted from the north direction (city center direction). Nitrogen oxides such as HONO and NO 2 are important for the production of hydroxyl radical (OH) and oxidative capacity in the troposphere. In this study, the averaged value of OH production rate from HONO is about 0.63 ppb/hr and maximum value of ratio between OH production from HONO and from (HONO+O 3) is > 93% before12:00 in Leshan. In addition, combustion emission contributes to 26% for the source of HONO in Leshan, and we found that more NO 2 being converted to HONO under the conditions with high aerosol extinction coefficient and high relative humidity is also a dominant factor for the secondary produce of HONO. [Display omitted] [ABSTRACT FROM AUTHOR]

Intensive observations and WRF‐Chem simulations are applied in this study to investigate the adverse impacts of regional transport on the PM2.5 (fine particulate matter; diameter ≤2.5 μm) changes in Shanghai during the Coronavirus Disease 2019 lockdown. As the local atmospheric oxidation capacity was observed to be generally weakened, strong regional transport carried by the frequent westerly winds is suggested to be the main driver of the unexpected pollution episodes, increasing the input of both primary and secondary aerosols. Contributing 40%–80% to the PM2.5, the transport contributed aerosols are simulated to exhibit less decreases (13.2%–21.8%) than the local particles (37.1%–64.8%) in urban Shanghai due to the lockdown, which largely results from the less decreased industrial and residential emissions in surrounding provinces. To reduce the influence of the transport, synergetic emission control, especially synergetic ammonia control, measures are proved to be effective strategies, which need to be considered in future regulations. Plain Language Summary: The anthropogenic emissions were sharply reduced in China due to the lockdown measures during the Coronavirus Disease 2019 pandemic. However, the reduced emissions did not lead to expected decreases in fine particulate matter in Shanghai. To understand why haze pollution still occurred during the lockdown, intensive observations and a variety of simulations using the regional chemical transport model were conducted in this study. Contributing 40−80% to the fine particles in Shanghai, the strong transport of air pollutants carried by the frequent westerly winds is found to be the main driver of the observed pollution episodes, which brings substantial primary and secondary aerosols to the city. Compared to those originated from the local sources, the transport contributed aerosols are simulated to be less affected by the intervention measures, which can be largely attributed to the less decreased industrial and residential emissions in Jiangsu, Zhejiang, and Anhui and enhanced aerosol formation during the transport. Synergetic emission control measures, including reductions in both the traditional regulated emissions and agricultural emissions, in the Yangtze River Delta region are proved to be effective in mitigating the adverse impacts of the transport, which provide practical implications for future pollution control strategies in cities like Shanghai. Key Points: PM2.5 pollution in Shanghai were mostly attributed to the regional transport carried by frequent westerly winds during the COVID‐lockdownThe transport contributed aerosols in Shanghai are less affected by the lockdown measures due to the less decreased surrounding emissionsSynergetic emission control measures, especially those on ammonia emissions, are effective in mitigating the adverse transport impacts [ABSTRACT FROM AUTHOR]

Air quality has improved significantly in the recent 10 years, but there is still a wide gap compared to the WHO AQG level. The concentration of PM 2.5 during OMICRON in 2022 was 21.7 μg m−3, which marked the lowest historical record under the lockdown status of the whole urban area, still exceeding the national Level 1 standard. PMF results have shown that the contributions of ship emissions increased from 2020 to 2022 during the historical OMICRON episodes, with growth rates of 9.7% and 10.7%, respectively. AIS data indicated an overall increase in shipping activities around Shanghai during the OMICRON22-2021 period. The strict control of urban activities during the silent period in 2022 reduced ship activities by 21.0% and 31.8% in the ChongMingMsa and WuSongMsa ranges close to Shanghai, respectively. However, significant growth was observed in the sea regions of ShanghaiMsa and ZhouShan-NingBoMsa, with growth rates of 44.2% and 33.7%, respectively. The total number of anchored ships in the sea region of YangShanGangMsa increased by 56.7%. CWT analysis indicated that the lockdown measures only changed the distributions of the ship emissions. More forceful measures for the reductions of the ship emissions should be considered. [Display omitted] • PM 2.5 concentration under the lockdown status still exceeded the national Level 1 standard and WHO AQG level. • The concentration of ship emission marker-Vanadium decreased with the benefit of ECA,but increased after 2020. • No obvious reduction of ship activities and emissions were found around Shanghai during OMICRON episode. • Epidemic events changed the distributions of the ship activities and the related emissions. [ABSTRACT FROM AUTHOR]

The COVID-19 epidemic broke out in Wuhan, Hubei in December 2019 and in January 2020 and was later transmitted to the entire country. Quarantine measures during Chinese New Year effectively alleviated the spread of the epidemic, but they simultaneously resulted in a decline in anthropogenic emissions from industry, transportation, and import and export of goods. Herein, we present the major chemical composition of non-refractory PM 2.5 (NR-PM 2.5) and the concentrations of gaseous pollutants in an urban site in Shanghai before and during the quarantine period of the COVID-19 epidemic, which was Jan. 8―23 and Jan. 24―Feb. 8, respectively. The observed results show that the reduction in PM 2.5 can be mainly attributed to decreasing concentrations of nitrate and primary aerosols. Nitrate accounted for 37% of NR-PM 2.5 before the quarantine period when there was no emission reduction. During the quarantine period, the nitrate concentration decreased by approximately 60%, which is attributed to a reduction in the NO x concentration. Ammonium, as the main balancing cation, showed an approximately 45% simultaneous decrease in concentration. The concentrations of chloride and hydrocarbon-like organic aerosols from primary emissions also declined due to limited human activities. By contrast, sulphate and oxygenated organic aerosols showed a slight decrease in concentration, with their contributions increasing to 27% and 18%, respectively, during the quarantine period, which resulted in two pollution episodes with PM 2.5 exceeding 100 μg/m3. This study provides a better understanding of the impact of quarantine measures on variations of the PM 2.5 concentration and chemical compositions. Atmospheric oxidation capacities based on the oxidant (O x = O 3 + NO 2) and oxidation ratios have been discussed for elucidating the source and formation of haze in an environment with lower anthropogenic emissions. With increasing contribution of secondary aerosols, lower NO x and nitrate concentrations did not completely avoid haze in Shanghai during the epidemic. Unlabelled Image • Quarantine measures led to a reduction in the concentrations of PM 2.5 , SO 2 , NO x , and CO in Shanghai. • Reduction in NO x led to increasing O 3 and decreasing nitrate. • Reduction in PM 2.5 is attributed to the decreasing concentrations of primary aerosols and nitrate. • The increasing contribution of sulphate and OOA inhibited further PM 2.5 reduction. [ABSTRACT FROM AUTHOR]

At the end of 2019, a novel coronavirus, designated as SARS-CoV-2, emerged in Wuhan, China and was identified as the causal pathogen of COVID-19. The epidemic scale of COVID-19 has increased dramatically, with confirmed cases increasing across China and globally. Understanding the potential affecting factors involved in COVID-19 transmission will be of great significance in containing the spread of the epidemic. Environmental and meteorological factors might impact the occurrence of COVID-19, as these have been linked to various diseases, including severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS), whose causative pathogens belong to the same virus family as SARS-CoV-2. We collected daily data of COVID-19 confirmed cases, air quality and meteorological variables of 33 locations in China for the outbreak period of 29 January 2020 to 15 February 2020. The association between air quality index (AQI) and confirmed cases was estimated through a Poisson regression model, and the effects of temperature and humidity on the AQI-confirmed cases association were analyzed. The results show that the effect of AQI on confirmed cases associated with an increase in each unit of AQI was statistically significant in several cities. The lag effect of AQI on the confirmed cases was statistically significant on lag day 1 (relative risk (RR) = 1.0009, 95% confidence interval (CI): 1.0004, 1.0013), day 2 (RR = 1.0007, 95% CI: 1.0003, 1.0012) and day 3 (RR = 1.0008, 95% CI: 1.0003, 1.0012). The AQI effect on the confirmed cases might be stronger in the temperature range of 10 °C ≤ T < 20 °C than in other temperature ranges, while the RR of COVID-19 transmission associated with AQI was higher in the relative humidity (RH) range of 10% ≤ RH < 20%. Results may suggest an enhanced impact of AQI on the COVID-19 spread under low RH. Unlabelled Image • AQI - COVID-19-confirmed cases association is statistically significant in some cities. • Lag effect of AQI on confirmed cases is statistically significant on lag 1–3 days. • AQI effect on the confirmed cases in temperature range of 10–20 °C may be stronger. • Impact of AQI on the spread of COVID-19 may be enhanced under low relative humidity. [ABSTRACT FROM AUTHOR]

Findings are inconsistent in studies for impacts of outdoor air pollutants on airway health in childhood. In this paper, we collected data regarding airway and allergic symptoms in the past year before a survey in 13,335 preschoolers from a cross-sectional study. Daily averaged concentrations of ambient sulphur dioxide (SO 2), nitrogen dioxide (NO 2), and particulate matter with an aerodynamic diameter ≤10 μm (PM 10) in the past year before the survey were collected in the kindergarten-located district. We investigated associations of 12-month average concentrations of these pollutants with childhood airway and allergic symptoms. In the two-level (district-child) logistic regression analyses, exposure to higher level of NO 2 and of PM 10 increased odds of wheeze symptoms (adjusted OR, 95%CI: 1.03, 1.01–1.05 for per 3.0 μg/m3 increase in NO 2 ; 1.22, 1.09–1.39 for per 7.6 μg/m3 increase in PM 10), wheeze with a cold (1.03, 1.01–1.06; 1.22, 1.08–1.39), dry cough during night (1.05, 1.03–1.08; 1.23, 1.09–1.40), rhinitis symptoms (1.11, 1.08–1.13; 1.32, 1.07–1.63), rhinitis on pet (1.11, 1.05–1.18; 1.37, 0.95–1.98) and pollen (1.12, 1.03–1.21; 1.23, 0.84–1.82) exposure, eczema symptoms (1.09, 1.05–1.12; 1.22, 0.98–1.52), and lack of sleep due to eczema (1.12, 1.07–1.18; 1.58, 1.25–1.98). Exposures to NO 2 and PM 10 were also significantly and positively associated with the accumulative score of airway symptoms. Similar positive associations were found of NO 2 and of PM 10 with the individual symptoms and symptom scores among preschoolers from different kindergarten-located district. These results indicate that ambient NO 2 and PM 10 likely are risk factors for airway and allergic symptoms in childhood in Shanghai, China. • We surveyed 13,335 preschoolers from five districts of Shanghai, China. • We studied effects of ambient NO 2 , SO 2 and PM 10 on airway and allergic diseases. • Periods of pollutant exposures and disease appearances were same in one year. • NO 2 and PM 10 was associated with increased risks of most studied diseases. [ABSTRACT FROM AUTHOR]

CO 2 and CH 4 are the two most potent greenhouse gases (GHGs) in the atmosphere. They are frequently monitored at background observatories, but less so in urban areas, especially in China. In this study, the temporal variations of urban atmospheric CO 2 and CH 4 , including seasonal, weekly, and diurnal characteristics, were obtained based on one year of continuous measurement in the megacity Shanghai. Probable anthropogenic sources were further investigated through relationships among GHGs and atmospheric pollutants. Potential sources regions and transport pathways of GHGs were studied in association with meteorological conditions. The annual average concentrations of CO 2 and CH 4 were 428.36 ± 13.96 ppm and 2154 ± 190 ppb, respectively, which were higher than those at global and regional background observatories. The highest CO 2 concentration appeared in winter and the lowest in autumn, whereas CH 4 values were highest in summer and lowest in spring. Both CO 2 and CH 4 showed strong diurnal variations, but only CO 2 exhibited seasonal and weekly differences due to the variation of emission sources and plant photosynthesis in Shanghai and the surrounding Yangtze River Delta (YRD). CO 2 and combustion-derived air pollutants were co-emitted from similar sources and co-transported to the research site, as demonstrated by correlation analysis. Furthermore, the correlation analysis also suggested some neglected anthropogenic combustion sources of CH 4 in Shanghai, besides the traditional biogenic emissions from landfills, wetlands, paddy fields, and dairy farms. The anthropogenic CO 2 concentration in urban Shanghai estimated from a CO 2 -CO regression model was 14.98 ± 5.09 ppm, together with a background concentration of 413.31 ± 7.07 ppm, which was higher than at global background sites but lower than at the nearby regional background Lin'an station. GHGs were accumulated from local sources under stable weather conditions and transported from remote sources at high wind speeds. Air masses from "super-emitters" north and south of the observation site contributed most of the elevation in GHGs concentration above their annual averages. Considering the co-emissions of GHGs and air pollutants from carbon-containing material combustion and use, and the potential of methane to generate O 3 in the urban environment, reduction of CO 2 and CH 4 together with air pollutants could benefit both climate and air quality in Shanghai and the surrounding YRD. Unlabelled Image • CO 2 and CH 4 were measured together with air pollutants and meteorological conditions in urban Shanghai. • Both CO 2 and CH 4 showed diurnal variations, but only CO 2 showed seasonal and weekday effects. • Anthropogenic sources affected the elevated concentrations of GHGs in urban environment. • GHGs were accumulated from local sources in stable, together with transport from remote sources. • Joint control of GHGs and air pollutants could benefit both climate and air quality. [ABSTRACT FROM AUTHOR]

Shanghai, a metropolitan city in China, has suffered from severe air pollution, especially PM 2.5 , in the last few years. Up to now the contribution of local emission and regional transport to the formation of haze in Shanghai remains unclear. With an aim to characterize the mechanism of haze formation in Shanghai, the present paper attempted to provide an overview of a tethered balloon-based field campaign. According to the backward trajectories, the air mass traveling slowly from Jiangsu province accounted for the highest PM 2.5 concentration (66 ± 20 μg/m3). Seventy vertical profiles of PM 2.5 , NO, NO 2 , SO 2 and O 3 within 1000 m were obtained, through which a comparison study on the characteristics of the vertical distributions of air pollutants on clean days and haze days was conducted. When altitude increased, clearly decreasing pattern of PM 2.5 , NO, and NO 2 was observed during the field campaign. Due to the low atmospheric boundary layer, the diffusion of air pollutants was suppressed, which favored the formation of haze. The results of the generalized additive model revealed NO 2 could the most significant factor influencing the vertical distribution of PM 2.5 in both clean and haze days. This study provides new insight into the sources and vertical distribution of PM 2.5 , which could offer references for air pollution modeling. Unlabelled Image • NO 2 was the most significant factor influencing the vertical distribution of PM 2.5. • Polluted air mass from neighboring provinces could influence the air in Shanghai. • Low ABL favored the accumulation of air pollutants in haze days. [ABSTRACT FROM AUTHOR]

With the implementation of the ultra-low emission policy in China, emission factors (EFs) of power plant pollutants are constantly changing. Emission inventories developed using the recommended EFs contain high levels of uncertainty and it is difficult to achieve a high temporal resolution. Detailed sulfur dioxide (SO 2), nitrogen oxides (NOx), and particulate matter (PM) emission data based on a continuous emission monitoring system (CEMS) were obtained from 33 units at 13 power plants in Shanghai in 2017. The data were used to develop an hourly unit-based emission inventory and to devise updated EFs for coal-fired power plants. Emissions of SO 2 , NOx, and PM typically met the ultra-low emission limit, with total emissions of SO 2 , NOx, and PM of 2895.0, 5348.3, and 503.8 tons, respectively. Emission proportions of SO 2 and NOx for 300–600, 600–1000, and above 1000 MW units were similar, while the emission proportion of PM decreased with an increase in unit capacity. Emissions of SO 2 , NOx, and PM displayed similar monthly variations, peaking in winter and summer. Diurnal hourly variations of SO 2 , NOx, and PM emissions displayed a bimodal trend, with higher emissions at night on weekends than on weekdays. EFs based on CEMS (EF C) of SO 2 , NOx, and PM were 0.10, 0.36, and 0.04 g kg−1 of coal, respectively, which were one or two orders of magnitude lower than the widely-used EFs and 4–30 times lower than EFs based on the mass balance approach. After replacing the recommended fixed decontamination efficiencies with individually fitted values, the calculated EFs were consistent with the corresponding EF C and discrepancies were further reduced. The new inventory and updated EFs will enable a better understanding of the temporal variations of power plant emissions and reduce the uncertainty caused by the overestimation of EFs after the implementation of ultra-low emissions technology. Unlabelled Image • An hourly-resolution unit-based emission inventory and updated emission factors in coal-fired power plants were developed. • There was a significant difference in the diurnal emission trend between workdays and non-weekdays • The EFs of SO 2 , NO x , and PM were one or two orders of magnitude lower than previously reported. [ABSTRACT FROM AUTHOR]

Assessing the impact of garbage classification on air pollution in rapidly developing economic regions is particularly necessary in light of the current policy trends. We evaluated the resulting changes in air pollution levels before and after garbage classification based on a three-year field observation using high-resolution online instruments in a municipal solid waste comprehensive disposal base. A targeted scheme is proposed to analyze the variation characteristics of major sources in a complex multi-source environment (Environments with multiple sources of pollution). We found that the concentrations of hydrogen sulfide (H 2 S) and volatile organic compounds (VOCs) in ambient air decreased by 48% and 43% respectively after garbage classification, and their spike frequency was controlled at approximately 0.01. The average H 2 S and VOC concentrations were generally low during the daytime, but relatively high during the nighttime because of meteorology and photochemistry. The ozone formation potential of the base decreased by 56%. Alternatively, emissions from transportation and combustion sources increased, while landfill pollution decreased owing to changes in the method of waste disposal. This finding suggests that garbage classification is an effective means of improving the air quality. This new scheme has a good potential in actual research scenarios. [Display omitted] [ABSTRACT FROM AUTHOR]

New particle formation (NPF) is one main source of atmospheric aerosols and plays an important role in global climate by contributing up to two thirds of the atmospheric cloud condensation nuclei. Numerous studies on characteristics and mechanisms of near-surface NPF have been conducted in last decades. However, the characteristics of NPF around the top of the planetary boundary layer (PBL) remains unclear due to the limitations of vertical measurements. In this study, a tethered airship onboard with advanced particle instruments was deployed for directly measurement of the NPF exactly above and under the top of the PBL in the Yangtze River Delta (YRD) of eastern China in December 2017. Coupled with the real time ground Lidar observation, we successfully conducted measurement of aerosol size distribution, chemical components of aerosol and gas pollutants with 100 m above/under the top of the PBL. Despite not being observed within the PBL during the flight and at three ground sites in YRD, NPF event with the growth rate of 3.8 nm/h was detected above the PBL. High oxidizing capacity, enough condensable vapors and low condensation sink above the PBL favor the onset of NPF. Model simulation and the aerosol chemical composition result indicate the important role of gaseous sulfuric acid in NPF and its subsequent growth in the upper atmosphere. Our study highlights the potential mechanism of NPF above the PBL and the need of direct vertical measurements to better understand NPF in the atmosphere and its climate effect. • Tethered airship platform made it possible to understand subtle vertical structure. • Model forecast and online measurements can reduce the risk of experiment. • New particle formation was detected only above the planetary boundary layer. • The growth rate above the planetary boundary layer was about 3.8 nm/h. • High H 2 SO 4 values above planetary boundary layer favor the new particle formation. [ABSTRACT FROM AUTHOR]

Background: Fetal growth restriction (FGR) is not only a major determinant of perinatal morbidity and mortality but also leads to adverse health effects in later life. Over the past decade, numerous studies have indicated that maternal exposure to ambient air pollution has been a risk factor for abnormal fetal growth in developed countries where PM2.5 levels are relatively low. However, studies in highly polluted regions, such as China, and studies that rely on assessments in utero are scarce.Methods: A total of 7965 women were selected from 11,441 women from the Shanghai Maternity and Infant Living Environment (SMILE) cohort who were pregnant between January 1, 2014, and April 30, 2015. From January 1, 2014, to April 30, 2015, weekly average PM2.5 values from 53 monitors were calculated and the inverse distance weighted (IDW) method was used to create a Shanghai pollution surface map according to the participants residential addresses. Individual exposure was the average PM2.5 value of every gestational week between the first gestational week and one week before the ultrasound measurement date (the range of measurements per participant was 1 to 10). Repeated fetal ultrasound measurements during gestational weeks 14~40 were selected. The estimated fetal weight (EFW) was calculated by biparietal diameter (BPD), abdominal circumference (AC), and femur length (FL) formulas. In total, 29,926 ultrasound measurements were analysed. Demographic variables, other pollutants (SO2, NO2, PM10 and O3) and relative humidity and temperature were controlled for potential confounding through generalized estimating equations (GEE).Results: The full model showed that with each 10 μg/m3 increase in PM2.5 exposure, the means (mm) of AC, BPD, FL decreased by 5.48 (- 9.06, - 1.91), 5.57 (- 6.66, - 4.47), and 5.47 (- 6.39, - 4.55), respectively; the mean EFW decreased by 14.49 (- 16.05, - 13.49) grams by Hadlock's third formula and 13.56 (- 14.71, - 12.50) grams by Shepard's formula with each 10 μg/m3 increase in PM2.5 exposure.Conclusions: A negative correlation existed between maternal PM2.5 exposure during pregnancy and fetal growth indicators, which may increase the risk of fetal growth restriction. [ABSTRACT FROM AUTHOR]

Abstract Background Nitrogen dioxide (NO 2) is a typical indicator of traffic-related air pollution, and few studies with exposure assessment of high resolution have been conducted to explore its association with preterm birth in China. Objectives To investigate the association between NO 2 exposure based on a land use regression (LUR) model and preterm birth in Shanghai, China. Methods A retrospective cohort study was performed among 25,493 singleton pregnancies in a major maternity hospital in Shanghai, China, from 2014 to 2015. A temporally adjusted LUR model was used to predict the prenatal exposure to NO 2 based on residence address of each gravida. Logistic regression was performed to evaluate the associations of ambient NO 2 exposure with preterm birth during six exposure periods, including the entire pregnancy, the first trimester, the second trimester, the third trimester, the last month, and the last week before delivery. Sensitivity analysis with a matched case-control design was conducted to test the robustness of the association between NO 2 exposure and preterm birth. Results The average NO 2 concentrations during the entire pregnancy was 48.23 µg/m3 among all participants. A 10 µg/m3 increase in NO 2 concentrations was associated with preterm birth, with an adjusted odds ratio of 1.03 (95% confidence interval [CI]: 0.96,1.10) for exposures during the entire pregnancy, 1.00 (95%CI: 0.95,1.06) in the first trimester, 1.01 (95%CI: 0.96,1.07) in the second trimester, 1.07 (95%CI: 1.02,1.13) in the third trimester, 1.10 (95%CI: 1.04,1.15) and 1.05 (95%CI: 1.00,1.09) in the month and week before delivery, respectively. The results of the matched case–control analysis were generally consistent with those of main analyses. Conclusion NO 2 may increase the risk of preterm birth, especially for exposures during the third trimester, the month and the week before delivery in Shanghai, China. Graphical abstract fx1 Highlights • The first study evaluating the impacts of LUR-derived NO 2 on preterm birth in China. • The LUR model of NO 2 has a high spatial resolution and predictive ability. • The impacts of NO 2 exposure on preterm birth varied by different trimesters. • NO 2 exposure during the third trimester may increase the risk of preterm birth. [ABSTRACT FROM AUTHOR]

Abstract To reduce air pollution within a 300 km radius from Hangzhou (the capital city of Zhejiang Province in East China) for the 2016 G20 summit (9/4–9/5), the 14-day (8/24–9/6) stringent pollution control measures were implemented in Shanghai. Changes in atmospheric concentrations during the same 14-day period from 2014 to 2016 were examined at two Supersites, i.e., urban Pudong site (PD) and Dianshan Lake regional site (DSL). Up to 50% reductions were found for PM 2.5 , with 13.1% and 9.7% reductions for SO 2 and NO 2 , respectively. No apparent improvements were found for 8-h average O 3 concentrations. Large reductions were also found for SO 4 2− (51.4%), NO 3 − (68.8%), and NH 4 + (84.4%), on average. Elevated coefficient of divergence values (0.52–0.56) suggested that pollutant sources differed at the two sites. Biomass burning, resuspended dust, combustion, iron and steel industry, sea salt, secondary aerosol, and vehicle exhaust were identified at the DSL site by Positive Matrix Factorization (PMF). Secondary aerosol and vehicle exhaust accounted for 45.7% of PM 2.5 mass, followed 11.2%–13.7% each by industry, resuspended dust, and coal and oil combustion. Graphical abstract Unlabelled Image Highlights • Effectiveness of the pollution control measures was evaluated for the G20 summit. • Concentrations of most of criteria air pollutants reduced whereas O 3 elevated. • Impacts of local emissions and regional transport were analyzed at two Supersites. • Secondary aerosols and vehicle exhaust remained the top two sources of PM 2.5. [ABSTRACT FROM AUTHOR]

Abstract Multi-AXis-Differential Optical Absorption Spectroscopy (MAX-DOAS) measurements were performed to remote sensing the aerosol vertical profiles in suburb area of Shanghai, China from April to December 2017. The retrieval of aerosol extinction was based on the optimal estimation method combing the measured oxygen dimer O 4 absorption with simulation of forward radiative transfer model. It suggests that the employment of O 4 correction factor (CF O4) for daily aerosol retrieval should be adjusted, which includes three typical cases that a fixed CF O4 , no usage of CF O4 and different CF O4 in the morning and afternoon. In cases of using CF O4 , elevation angle dependent CF O 4 (α) were further proposed. Moreover, the retrieval results can be improved if the local sounding data of atmospheric temperature and pressure profiles were introduced into the forward radiative transfer model without utilizing additional CF O4. Afterwards, the retrieved Aerosol Optical Depth (AOD) and the surface Aerosol Extinction Coefficient (AEC) was in a good agreement with the AOD obtained from sun photometer observations and in-suit PM 2.5 concentrations, with a correlation coefficient R of 0.866 and 0.833, respectively. Besides, the vertical AEC profiles retrieved by MAX-DOAS were also validated well by the co-located lidar measurement. It can be found that the particles were mainly distributed below 1 km, and the maximum AEC usually appeared in the lowest 300 m and decreased with the altitudes. The averaged AEC within 1 km varied from 0.20 to 0.75 km−1, 0.25 to 1.08 km−1, 0.55 to 2.45 km−1 and 0.70 to 2.75 km−1 under different air quality of Grade II, III, IV and V. The sounding meteorological parameters and backward trajectories of air masses were integrated to diagnose the influencing factor of AEC at different altitudes, which illustrated that the AEC levels at lowest layer were impacted by the long distance transportation of air pollutants from north-northwest and regional local air pollution nearby during the winter time. The study shows that ground-based MAX-DOAS observation is powerful remote sensing technique to provide better understanding of aerosol properties at both ground surface and higher altitudes. Highlights • Aerosol vertical distribution were obtained by MAX-DOAS measurements in Shanghai. • O 4 correction factor (CF O4) need to be adjusted in the aerosol retrieval scheme. • Using local temperature and pressure profiles can improve the aerosol retrieval. • MAX-DOAS remote sensing are well validated by other auxiliary datasets. • High aerosol extinction usually occurred at the lowest layer below 0.3 km in winter. [ABSTRACT FROM AUTHOR]

Abstract Fine particulate matter (PM 2.5) has recently been associated with the activation of the hypothalamus–pituitary–adrenal (HPA) axis, increasing cardiometabolic risks. However, it is unknown which constituents of PM 2.5 were mainly responsible for these associations. In a longitudinal panel study with 4 repeated measurements among 43 college students in Shanghai, China, we measured serum levels of corticotropin releasing hormone (CRH), adrenocorticotropic hormone (ACTH) and cortisol, as indicators of HPA axis activation. Then, we evaluated the associations of 22 constituents of PM 2.5 with these stress hormones using linear mixed-effect models. During the study period, the average daily concentration of PM 2.5 was 41.1 μg/m3. We found that short-term exposure to PM 2.5 was associated with elevated levels of the 3 stress hormones. We observed that water-soluble inorganic ions, especially nitrate (NO 3 −) and ammonium, had stronger influences on 3 hormones. Six metallic elements, including Zn, Mn, Cu, Fe, Br, and Cr, had positive but generally instable associations with 3 hormones. The effects of organic carbon and elemental carbon on hormones were generally weak. When correcting for multiple comparisons using false discovery rate, NO 3 − was still significantly associated with CRH, but other important associations turned to be insignificant. An interquartile range increase in NO 3 − on the previous day were associated with 12.13% increase (95% confidence interval: 4.45%, 20.37%) in CRH. Our findings suggested that water-soluble inorganic constituents of PM 2.5 (especially, NO 3 −) might have stronger influences on the activation of HPA axis than carbonaceous and elemental components. Highlights • PM 2.5 may activate the HPA axis by increasing the secretion of stress hormones. • PM 2.5 was associated with CRH and ACTH at lag 1 d and with cortisol at lag 2 d. • NO 3 − might have stronger influence on the HPA axis activation. • OC, EC and metals in PM 2.5 might have weak and instable impacts on the HPA axis. [ABSTRACT FROM AUTHOR]

Abstract To investigate formation mechanisms of secondary organic carbon (SOC) in Eastern China, measurements were conducted in an urban site in Shanghai in the summer of 2015. A period of high O 3 concentrations (daily peak > 120 ppb) was observed, during which daily maximum SOC concentrations exceeding 9.0 μg/(C·m3). Diurnal variations of SOC concentration and SOC/organic carbon (OC) ratio exhibited both daytime and nighttime peaks. The SOC concentrations correlated well with O x (= O 3 + NO 2) and relative humidity in the daytime and nighttime, respectively, suggesting that secondary organic aerosol formation in Shanghai is driven by both photochemical production and aqueous phase reactions. Single particle mass spectrometry was used to examine the formation pathways of SOC. Along with the daytime increase of SOC, the number fraction of elemental carbon (EC) particles coated with OC quickly increased from 38.1% to 61.9% in the size range of 250–2000 nm, which was likely due to gas-to-particle partitioning of photochemically generated semi-volatile organic compounds onto EC particles. In the nighttime, particles rich in OC components were highly hygroscopic, and number fraction of these particles correlated well with relative humidity and SOC/OC nocturnal peaks. Meanwhile, as an aqueous-phase SOC tracer, particles that contained oxalate-Fe(III) complex also peaked at night. These observations suggested that aqueous-phase processes had an important contribution to the SOC nighttime formation. The influence of aerosol acidity on SOC formation was studied by both bulk and single particle level measurements, suggesting that the aqueous-phase formation of SOC was enhanced by particle acidity. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

In order to investigate the relationship between outdoor air pollution and sick building syndrome (SBS) symptoms, the CCHH (China, Children, Home, Health) group in Shanghai conducted a cross-sectional survey on the current incidence of SBS symptoms among residents in five districts of Shanghai during April 2011–April 2012. It also collected the related outdoor air pollutants data from Shanghai environmental monitoring center (SEMC), including nitrogen dioxide (NO 2 ), sulfur dioxide (SO 2 ) and particles with aerodynamic diameter less than 10 µm (PM 10 ). The logistic regression models were used in this paper to study the associations between air pollutants and SBS symptoms. Results were found that the daily mean concentrations of NO 2 and SO 2 met standard requirement, but that of PM 10 exceeded the limit values of the standard in China during this survey. The significant differences were found between the pollutants concentration in urban and suburban area. In addition, the incidences of three categories of SBS symptoms among residents were 79.1% for general symptoms (GS), 65.2% for mucous membrane symptoms (MS) and 35.7% for skin symptoms (SS), respectively. Multiple logistic regression analysis by two case studies illustrated that three outdoor air pollutants, both their concentration quartiles and equal increment, were all associated to and taken as the risk factors for SBS symptoms, for GS OR NO2  = 1.62 (1.18–2.22), MS OR NO2  = 1.58 (1.21–2.06) and SS OR PM10  = 1.21 (1.09–1.35). Furthermore, the new pollutants expressed as the mixtures of their combination were also significantly associated with part of the SBS symptoms. The synthetic air quality indexes of all surveyed residents were calculated as III-level, which represented mild pollution. Therefore, it would be an effective way to decrease the incidence of SBS symptoms in residence to reduce the outdoor air pollution and control the penetration from outdoor to indoor environment. [ABSTRACT FROM AUTHOR]

Air pollution has become one of the most stubborn environmental problem in China, the traditional environmental monitoring mainly focus on the horizontal distribution of the pollutants, while it is still of great importance to have the knowledge of the vertical profiles of them. The present study, for the first time, attempted to acquire the vertical distributions of O 3 and one of its precursors, volatile organic compounds (VOCs) within 1000 m of lower troposphere by using a tethered balloon in the suburban of Shanghai, a Chinese megacity. We analyze the concentration and the ozone formation potential (OFP) at three height level of 50–350, 350–700, and 700–1000 m. According to our measurement, the total concentration of VOC decreased with the altitude increasing. In addition, the dominant species of OFP was alkene, aromatics, and alkene at height level of 50–350, 350–700 and 700–1000 m, respectively. Our results suggest that, in the morning, the fresh emission contributed a lot to the high concentration of benzene and toluene near ground. Furthermore, the regression analyzes showed toluene decreased faster than benzene in the troposphere. The VOC concentration can be used as initial values for numerical simulations of chemical reaction in the lower troposphere. [ABSTRACT FROM AUTHOR]

Evidence is limited regarding whether ambient monitoring can properly represent personal ozone exposure. We conducted a longitudinal panel study to measure personal exposure to ozone using real-time personal ozone monitors. Corresponding ambient ozone concentrations and possible influencing factors (meteorological conditions and activity patterns) were also collected. We used linear mixed-effect models to analyze personal-ambient ozone concentration associations and possible influencing factors. Ambient ozone concentrations were around two to three times higher than personal ozone (43.1 μg/m 3 on average) and their correlations were weak with small slopes (0.35) and marginal R square (R M 2 ) values (0.24). Larger R M 2 values were found under high temperature (>29.5 °C), low humidity (<62.1%), good ventilation conditions (>4 h) and for individuals spent longer time outdoors (>0.6 h). In final model, personal ozone exposure was positively associated with ambient concentrations and ventilation conditions, but inversely correlated with ambient temperature and humidity. The models explained >50% of personal ozone concentration variabilities. Our results highlight that ambient ozone concentration alone is not a suitable surrogate for individual exposure assessment. Meteorological conditions (temperature and humidity) and activity patterns (windows opening and outdoor activities) that affecting personal ozone exposure should be taken into account. [ABSTRACT FROM AUTHOR]