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Stroke is a significant global cause of disability and death, and its burden has been on the rise, while ambient air pollution has been conclusively linked to stroke incidence. However, knowledge about effects of atmospheric oxidation on stroke and its interactions with fine particles (PM 2.5 ) are still limited. In this study, we investigated the short-term effects of ambient NO 2 , O 3 , and their combined oxidation (O wt ) on first-ever stroke, based on data from the China National Stroke Screening Survey (CNSSS) conducted from 2013 to 2015. We found significant association between ambient NO 2 exposure at lag0 day with first-ever stroke, with a 13.1 % (95 % CI: 3.5 %, 23.6 %) increase in the first-ever stroke risk per 10 μg/m 3 exposure. We also found a significant interaction between NO 2 and PM 2.5 (p < 0.05): first-ever stroke risk increased 23.8 % (95 % CI: 9.6 %, 39.8 %) per 10 μg/m 3 NO 2 exposure in population exposed to higher PM 2.5 concentrations, while no significant association was found in population exposed to lower PM 2.5 concentrations. The results of stratified analyses indicated that physical inactivity enhanced the detrimental effects of O 3 and O wt exposure, while smoking and transient ischemic attack (TIA) history enhanced the detrimental effects of NO 2 exposure. However, TIA history appeared to mitigate the adverse effects of O 3 exposure. This study is helpful to better understand the impact of ambient oxidation on stroke, as well as its interaction with PM 2.5 , and has implications for policies and standards for atmospheric protection and governance., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Although meteorological conditions play a significant role in air pollution, research on their effects on the relationship between air pollutants is limited. In this study, trends of six criteria air pollutants were investigated from 15 air quality monitoring stations (AQMSs) in Ulsan, a multi-industrial city in South Korea, during 2015-2019. Unlike CO and O 3 , SO 2 , NO 2 , PM 10 , and PM 2.5 showed statistically significant decreasing trends over the period. The companion relationship between PM 2.5 and gaseous pollutants was evaluated by their correlations [R (PM 2.5 -GPs)]. R (PM 2.5 -NO 2 ) was relatively high at almost all AQMSs, whereas high R (PM 2.5 -SO 2 ) was observed near the petrochemical industrial complex, suggesting a great influence of local emissions (vehicles and industries). R (PM 2.5 -CO) and the standardized regression coefficients of CO obtained from the multiple linear regression model were the highest, indicating that combustion processes may significantly contribute to PM 2.5 . The effect of temperature (T) was more apparent on R (PM 2.5 -GPs) than that of relative humidity, with significant values under T > 15 °C. Moreover, R (PM 2.5 -O 3 ) was positive at the T range of 12-18 °C, suggesting that reducing GPs emitted by industrial facilities during May-June may control PM 2.5 and O 3 in Ulsan. The methodology demonstrated in this study can be further used for a better understanding of the influences of environmental factors on the secondary PM 2.5 formation from gaseous precursors and the R (PM 2.5 -O 3 )., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

According to the International Agency for Research on Cancer (IARC), airborne fine particulate matter (PM 2.5 ), which is categorized as a Group I carcinogen, was found to lead to predominantly lung as well as other cancer types in humans. Hepatocellular carcinoma (HCC) is endemic in Taiwan where it is the second and fourth foremost cause of cancer deaths in men and women, respectively. Taiwan's mortality rates for liver cancer vary considerably from one region to another, suggesting that the environment may exert some influence on deaths attributed to liver cancer. The aim of this investigation was to perform an ecologic study to examine the possible link between ambient PM 2.5 levels and risk of liver cancer in 66 in Taiwan municipalities. To undertake this investigation, annual PM 2.5 levels and age-standardized liver cancer mortality rates were calculated for male and female residents of these areas from 2010 to 2019. Data were tested using weighted-multiple regression analyses to compute adjusted risk ratio (RR) controlling for urbanization level and physician density. Annual PM 2.5 levels of each municipality were divided into tertiles. The adjusted RRs for males residing in those areas with intermediate tertile levels (21.85 to 28.21 ug/m 3 ) and the highest tertiles levels (28.22-31.23 ug/m 3 ) of PM 2.5 were 1.29 (95% CI = 1.25-1.46) and 1.41 (95% CI = 1.36-1.46), respectively. Women in these locations shared a similar risk, 1.32 (1.25-1.4) and 1.41 (1.34-1.49), respectively. Evidence indicated that PM 2.5 increased risk of mortality rates attributed to liver cancer in both men and women in Taiwan.

The influence of long-range transport (LRT) of air pollutants on neighboring regions and countries has been documented. The magnitude of LRT aerosols and related constituents can misdirect control strategies for local air quality management. In this study, we aimed to quantify PM 2.5 (diameter less than 2.5 μm, PM 2.5 ) and associated metals derived from local sources and LRT in different geographic locations in Taiwan using advanced receptor models. We collected daily PM 2.5 samples (n = ∼1000) and analyzed 28 metals every three days from 2016 to 2018 in the northern, central-south, eastern, and southern areas of Taiwan. We first used a machine learning technique with a cluster algorithm coupled with a backward trajectory to classify local, regional, and LRT-related aerosols. We then quantified the source contributions with a positive matrix factorization (PMF) model for Taiwan weighted by region-specific populations. The northern and eastern regions were found to be more vulnerable to LRT-related PM 2.5 and metals than the central-south and southern regions in Taiwan. The LRT increased Pb and As concentrations by 90-200% and ∼40% in the northern and central-south regions. Ambient PM 2.5 -metals mainly originated from local traffic-related emissions in the northern, central-south, and southern regions, whereas oil combustion was the primary source of PM 2.5 -metals in the eastern region. By subtracting the influence from the LRT, the contributions of domestic emission sources to ambient PM 2.5 metals in Taiwan were 35% from traffic-related emission, 17% from non-ferrous metallurgy, 13% from iron ore and steel factories, 12% from coal combustion, 12% from oil combustion, 10% from incinerator emissions, and <1% from cement manufacturing emissions. This study proposed an advanced method for refining local source contributions to ambient PM 2.5 metals in Taiwan, which provides useful information on regional control strategies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Residential solid fuel combustion (RSFC) is an important source of PM 2.5 . Here we investigate the cytotoxicity of primarily emitted and photochemically aged PM 2.5 to A549 cells. Owing to the formation of water-soluble ions and organics (e.g., oPAHs and nPAHs), emission factors of PM 2.5 were increased by 44.4% on average after 7-day equivalent photochemical aging, which greatly altered chemical profiles of freshly emitted PM 2.5 . Consequently, the cytotoxicity varied with aging duration that 2-day and 7-day aged PM 2.5 induced 22.5% and 35.1%, respectively, higher levels of reactive oxygen species than primary emissions. Similar increases were also observed for multi-cytotoxicity. Correlation analysis and western blot results collectively confirmed HO-1/Nrf-2 signaling pathway dominated the cytotoxicity of aged PM 2.5 from RSFC, which was regulated by the enhanced o-PAHs and n-PAHs during photochemical aging. Thus, aged and secondary aerosol exposure needs to be paid more attention due to the enhanced cytotoxicity and the vast crowd involved., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

To understand the influence of the energy structure (including solid fuel and clean energy) on air pollution, two comprehensive measurement campaigns were conducted in Baoding and Shanghai in late autumn and winter during 2017-2018. The chemical compositions, driving factors, regional transport of pollutants, and potential respiratory disease (RD) health risks of PM 2.5 for Baoding and Shanghai were analyzed. The results showed that the concentration of PM 2.5 in Baoding (156.9 ± 139.8 μg m -3 ) was 2.6 times of that in Shanghai (60.9 ± 45.9 μg m -3 ). The most important contributor to PM 2.5 in Baoding was organic matter (OM), while inorganic aerosols accounted for major fractions of PM 2.5 in Shanghai. Positive matrix factorization (PMF) results indicated that coal combustion (CC; 39%) accounted for the most in Baoding, followed by secondary aerosols (21%), biomass burning (BB; 20%), industrial emissions (14%), dust (3%), and vehicle exhaust (2%). However, the average contribution in Shanghai followed the order: secondary aerosols (44%), vehicle exhaust (36%), dust (11%), marine aerosols (6%), and BB (3%). The evolution of source contributions at different pollution levels revealed that haze episodes in Baoding and Shanghai were triggered by CC and secondary formation, respectively; however, the air quality on clean days in Baoding and Shanghai was affected mostly by BB and vehicle emissions, respectively. Potential source contribution function (PSCF) results suggested that CC in Baoding was primarily from local emissions, while BB was primarily from local and regional transport. Vehicle exhaust and secondary aerosols in Shanghai were mainly from local emissions and regional transport. The number of RD deaths related to haze episodes in Baoding and Shanghai were 215 (95% CI: 109, 319) and 76 (95% CI: 11, 135), respectively. This research also emphasized the importance of further attention to the usage of coal in Baoding and vehicle emissions in Shanghai., Competing Interests: Declaration of competing interest The authors declare that they have no commercial or associative interest that represents a conflict of interest in connection with this work submitted., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Background: Our hypothesis was that exposure to fine particulate matter (PM2.5) is related to abnormal cord insertion, which is categorized as a form of placental implantation abnormality. We investigated the association between exposure to total PM2.5 and its chemical components over the first trimester and abnormal cord insertion, which contributes to the occurrence of adverse birth outcomes., Methods: From the Japan Perinatal Registry Network database, we used data on 83 708 women who delivered singleton births at 39 cooperating hospitals in 23 Tokyo wards (2013-2015). We collected PM2.5 on a filter and measured daily concentrations of carbon and ion components. Then, we calculated the average concentrations over the first trimester (0-13 weeks of gestation) for each woman. A multilevel logistic-regression model with the hospital as a random effect was used to estimate the odds ratios (ORs) of abnormal cord insertion., Results: Among the 83 708 women (mean age at delivery = 33.7 years), the frequency of abnormal cord insertion was 4.5%, the median concentration [interquartile range (IQR)] of total PM2.5 was 16.1 (3.61) μg/m3 and the OR per IQR for total PM2.5 was 1.14 (95% confidence interval = 1.06-1.23). In the total PM2.5-adjusted models, total carbon, organic carbon, nitrate, ammonium and chloride were positively associated with abnormal insertion. Organic carbon was consistently, and nitrate tended to be, associated with specific types of abnormal insertion (marginal or velamentous cord insertion)., Conclusions: Exposure to total PM2.5 and some of its components over the first trimester increased the likelihood of abnormal cord insertion., (© The Author(s) 2021; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association.)

Zhengzhou is one of the most heavily polluted cities in China. This study collected samples of PM 2.5 (atmospheric fine particulate matter with aerodynamic diameter ≤ 2.5 μm) at five sites in different functional areas of Zhengzhou in 2016 to investigate the chemical properties and sources of PM 2.5 at three pollution levels, i.e., PM 2.5 ≤ 75 μg/m 3 (non-pollution, NP), 75 μg/m 3 < PM 2.5 ≤ 150 μg/m 3 (moderate pollution, MP), and PM 2.5 > 150 μg/m 3 (heavy pollution, HP). Chemical analysis was conducted, and source categories and potential source region were identified for PM 2.5 at different pollution levels. The health risks of toxic elements were evaluated. Results showed that the average PM 2.5 concentration in Zhengzhou was 119 μg/m 3 , and the sum of the concentrations of SO 4 2- , NO 3 - , and NH 4 + increased with the aggravation of pollution level (23, 42, and 114 μg/m 3 at NP, MP, and HP days, respectively). Positive Matrix Factorization analysis indicated that secondary aerosols, coal combustion, vehicle traffic, industrial processes, biomass burning, and dust were the main sources of PM 2.5 at three pollution levels, and accounted for 38.4%, 21.6%, 16.7%, 7.4%, 7.7%, and 8.1% on HP days, respectively. Trajectory clustering analysis showed that close-range transport was one of the dominant factors on HP days in Zhengzhou. The potential source areas were mainly located in Xinxiang, Kaifeng, Xuchang, and Pingdingshan. Significant risks existed in the non-carcinogenic risk of As (1.4-2.3) for children at three pollution levels and the non-carcinogenic risk of Pb (1.0-1.4) for children with NP and MP days., (© 2020. Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Ambient fine particle (PM 2.5 ) pollution is an important public health problem in China. Short-term ambient PM 2.5 exposure is associated with increased mortality of respiratory diseases. However, few evidence was available on the effect of exposure to ambient PM 2.5 on the years of life lost (YLL) from respiratory diseases in the elderly. Furthermore, birth season which is frequently applied as a proxy for environmental exposure in early life may influence the health outcome in the later life. Nevertheless, the modification effect of birth season on the relationship of PM 2.5 exposure and respiratory health need to be explored., Methods: A time-stratified case-crossover design was used to analyze YLL from respiratory diseases in the elderly related to ambient PM 2.5 exposure between 2013 and 2016 in Ningbo, China. The modification effect of birth season was explored by subgroup comparisons between different birth seasons., Results: Each 10 μg/m 3 increase in daily ambient PM 2.5 was associated with an increment of 1.61 (95% CI 0.12, 3.10) years in YLL from respiratory diseases in the elderly population. Individuals who were born in winter had significantly higher YLL from respiratory diseases associated with ambient PM 2.5 exposure than those who were born in other seasons., Conclusions: Birth season which reflects the early-life PM 2.5 exposure level that may influence the lung development has a potential effect on the disease burden of respiratory diseases related to ambient PM 2.5 exposure in later life. The results would provide theoretical basis to protect vulnerable population defined by birth season when exploring the adverse effects of ambient PM 2.5 in the respiratory health., (© 2021. The Author(s).)

The levels and characteristics of atmospheric metals vary in time and location, can result in various health impacts, which increases the challenge of air quality management. We aimed to investigate PM 2.5 -bound metals in multiple locations and propose a methodology for comparing metal elements across study regions and prioritizing source contributions through integrated health risk assessments. PM 2.5 -bound metals were collected in the urban, suburban, rural, and industrial regions of Taiwan between 2016 and 2018. We incorporated the positive matrix factorization (PMF) with health risk assessments (considering estimates of the margin of exposure (MOE) and excess cancer risk (ECR)) to prioritize sources for control. We found that the concentrations of Fe, Zn, V, Cu, and Mn (industry-related metals) were higher at the industrial site (Kaohsiung) and Ba, Cr, Ni, Mo, and Co (traffic-related metals) were higher at the urban site (Taipei). The rural site (Hualian) had good air quality, with low PM 2.5 and metal concentrations. Most metal concentrations were higher during the cold season for all study sites, except for the rural. Ambient concentrations of Mn, Cr, and Pb obtained from all study sites presents a higher health risk of concern. In Kaohsiung, south Taiwan, PM 2.5 -bound metals from the iron ore and steel factory is suggested as the first target for control based on the calculated health risks (MOE < 1 and ECR > 10 -6 ). Overall, we proposed an integrated strategy for initiating the source management prioritization of PM 2.5 -bound metals, which can aid an effort for policymaking., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Numerous epidemiologic studies demonstrated an association between an increase in levels of fine particles (particulate matter less than 2.5 um in diameter, PM 2.5 ) and elevation in the number of hospital admissions for cardiovascular diseases. Air pollution levels including PM 2.5 clearly decreased in Taipei City after the mass rapid transit (MRT) system began operations in 1996. The aim of this study was to investigate the extent of changes in the risk of daily hospital admissions for ischemic heart disease (IHD) over a 17-year period after the installation of a MRT system in Taipei. The full study was divided into Period 1 (1997-2000), total track length 65.1 km; Period 2 (2001-2008), total track length 75.8 km; and Period 3 (2009-2013), total track length 121.3 km. A time-stratified case-crossover analysis was conducted to estimate relative risk (RR) of hospital admissions for IHD for each 10 ug/m 3 increase in PM 2.5 for different periods. On cool days, the associated RR of IHD for Period 3 was consistently lower compared to period 2 in both our single- and two-pollutant models. However, the daily risk for IHD admissions was found to be significantly higher for period 3 compared to period 2 in our single-pollutant model and in our two-pollutant models (PM 2.5 + SO 2 ) on warm days. The basis for this difference is unknown. Data suggests that an MRT system may provide substantial health benefits, a finding that may be helpful to urban communities, urban planners, and public health specialists.

Background: While many studies reported the association between long-term exposure to particulate matter air pollution (PM) and cardiovascular disease (CVD), few studies focused on incidence with relatively high-dose exposure using a nationwide cohort. This study aimed to investigate the association between long-term exposure to PM 10 and PM 2.5 and incidence of CVD in a nationwide and population-based cohort in South Korea where the annual average concentration of PM 2.5 is above 20 μg/m 3 ., Methods: We selected 196,167 adults in the National Health Insurance Service-National Sample Cohort (NHIS-NSC) constructed based on the entire South Korean population. Incidence of four CVD subtypes including ischemic heart disease (IHD), myocardial infarction, heart failure, and stroke, and total CVD including all four was identified as the first diagnosis for 2007-2015. To assess individual exposures, we used annually-updated district-level residential addresses and district-specific PM concentrations predicted by a previously developed universal kriging prediction model. We computed individual-level long-term PM concentrations for four exposure windows: previous 1, 3, and 5 year(s) and 5 years before baseline. We applied time-dependent Cox proportional hazards models to estimate hazard ratios (HRs) of incident CVDs per 10 μg/m 3 increase in PM 10 and PM 2.5 after adjusting for individual- and area-level characteristics., Results: During 1,578,846 person-year, there were 33,580 cases of total incident CVD. Average PM 10 and PM 2.5 concentrations for the previous 5 years were 52.3 and 28.1 μg/m 3 , respectively. A 10 μg/m 3 increase in PM 2.5 exposed for the previous 5 years was associated with 4 and 10% increases in the incidence of total CVD (95% confidence interval: 0-9%) and IHD (4-16%), respectively. HRs tended to be higher with earlier exposure for IHD and more recent exposure for stroke. The estimated shape of the concentration-response relationship showed non-linear patterns. We did not find evidence of the association for PM 10 ., Conclusions: Using a population-based nationwide cohort exposed to relatively high PM concentration, this study confirmed the association between PM 2.5 and CVD incidence that was reported in previous studies mostly with low-dose environments. The magnitude and the shape of the association were generally consistent with previous findings.

Wuhan was the first city to adopt the lockdown measures to prevent COVID-19 spreading, which improved the air quality accordingly. This study investigated the variations in chemical compositions, source contributions, and regional transport of fine particles (PM 2.5 ) during January 23-February 22 of 2020, compared with the same period in 2019. The average mass concentration of PM 2.5 decreased from 72.9 μg m -3 (2019) to 45.9 μg m -3 (2020), by 27.0 μg m -3 . It was predominantly contributed by the emission reduction (92.0%), retrieved from a random forest tree approach. The main chemical species of PM 2.5 all decreased with the reductions ranging from 0.85 μg m -3 (chloride) to 9.86 μg m -3 (nitrate) (p < 0.01). Positive matrix factorization model indicated that the mass contributions of seven PM 2.5 sources all decreased. However, their contribution percentages varied from -11.0% (industrial processes) to 8.70% (secondary inorganic aerosol). Source contributions of PM 2.5 transported from potential geographical regions showed reductions with mean values ranging from 0.22 to 4.36 μg m -3 . However, increased contributions of firework burning, secondary inorganic aerosol, road dust, and vehicle emissions from transboundary transport were observed. This study highlighted the complex and nonlinear response of chemical compositions and sources of PM 2.5 to air pollution control measures, suggesting the importance of regional-joint control., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

While the measurement of particulate matter (PM) with a diameter of less than 2.5 μm (PM 2.5 ) has been conducted for personal exposure assessment, it remains unclear how models that integrate microenvironmental levels with resolved activity and location information predict personal exposure to PM. We comprehensively investigated PM 2.5 concentrations in various microenvironments and estimated personal exposure stratified by the microenvironment. A variety of microenvironments (>200 places and locations, divided into 23 components according to indoor, outdoor, and transit modes) in a community were selected to characterize PM 2.5 concentrations. Infiltration factors calculated from microenvironmental/central-site station (M/S) monitoring campaigns with time-activity patterns were used to estimate time-weighted exposure to PM 2.5 for university students. We evaluated exposures using a four-stage modeling approach and quantified the performance of each component. It was found that the SidePak monitor overestimated the concentration by 3.5 times as compared with the filter-based measurements. Higher mean concentrations of PM 2.5 were observed in the Taoist temple and night market microenvironments; in contrast, lower concentrations were observed in air-conditioned offices and car microenvironments. While the exposure model incorporating detailed time-location information and infiltration factors achieved the highest prediction (R 2  = 0.49) of personal exposure to PM 2.5 , the use of indoor, outdoor, and transit components for modeling also generated a consistent result (R 2  = 0.44)., Competing Interests: Declaration of competing interest I declare that there is no any conflict of interest for this study., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Most studies on the health effects of PM 2.5 (fine particulate matter with diameter smaller than 2.5 μm) use indirect indicators, such as mortality and number of hospital visits. Recent research shows that biomarkers can also be used to evaluate the health effects of PM 2.5 ; however, these biomarkers are not very common. Clinical laboratories can provide a significant amount of test data that have been proven to have important diagnostic value. Therefore, we use big data analysis methods to find the associations between clinical laboratory common test items and PM 2.5 exposure. Data related to air pollution and meteorological information between 2014 and 2016 were obtained from the China National Environmental Monitoring Centre and the China National Meteorological Information Center. Additionally, data of 27 common test items from the same period were collected from Changsha Central Hospital. Primary analyses included a generalized additive model to analyze the associations between PM 2.5 concentration and common test items; the model was adjusted for time trends, weather conditions (temperature and humidity), and days of the week. Furthermore, we adjusted the effects of other air pollutants, such as PM 10 , SO 2 , NO 2 , CO, and O 3 . 17 items such as TP, ALB, ALT, AST, TBIL, DBIL, UREA, CREA, UA, GLU, LDL, WBC, K, Cl, Ca, TT, and FIB were significantly positively associated with PM 2.5 concentration (P< 0.05) and have concentration-response relationship. After adjusting the effect of PM 10 +SO 2 +NO 2 +CO+O 3 , TP, ALB, ALT, AST, TBIL, DBIL, UREA, CREA, UA, GLU, WBC, Cl, and Ca were still significantly associated with PM 2.5 concentration (P< 0.05). This current study suggested that clinical laboratory common test items may be used to assess and predict the health effects of PM 2.5 on the population., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The annual average concentration of fine particles (PM 2.5 ) in Taiwan has been decreasing yearly. However, ambient haze has not abated and visibility is still poor. This study proposes a method for quantifying the source apportionment of ambient haze from various constituents, namely measured PM 2.5 , moisture, and secondary organic aerosols (SOA, represented by the sum of measured O 3 and NO 2 levels). This study's model-based demisting technology integrated image haze extracting technology with air quality monitoring data. The images for haze extraction were from the instant cameras of the Taiwan Environmental Protection Agency's air quality monitoring stations (AQMSs). Results indicate that haze constituents with the product of light extinction and scene depth have very high correlation (R 2  ≥ 0.8452), which demonstrate that this quantification approach was successful. The contributions of ambient haze from various constituents had quarterly and regional variations in the eastern, northern, central, and southern regions of Taiwan, which are slightly, lowly, moderately, and heavily contaminated areas, respectively. Each area was assigned a selected representative AQMS to represent its ambient haze characteristics. Cases where the dominant contributors to haze were PM 2.5 , moisture, and SOA were studied, in addition to the event days of PM 2.5 and ozone. We detail the limits of this approach, especially with regard to the use of images. This approach can help administrators understand the composition of ambient haze to generate effective haze strategies and policies. Residents can use this method to determine the health effects of daily haze., (Copyright © 2020. Published by Elsevier Inc.)

We examined the association of biological components in airborne particles, i.e., proteins and endotoxins, in outdoor air with asthma exacerbation in the Fukuoka metropolitan area, Fukuoka, Japan. Data on emergency department (ED) visits for asthma in children (age, 0-14 years) and adults (age, 15-64 years) were collected at a medical center from December 2014 to November 2015. One hundred eighty-one children and 143 adults visited the ED for asthma, and the weekly number of ED visits in children increased in autumn, i.e., September (second week) to November (first week). Fine (aerodynamic diameter ≤2.5 µm) and coarse (≥2.5 µm) particles were collected for 3 or 4 weeks per month, and protein and endotoxin concentrations were analyzed. Protein was largely prevalent in fine particles (0.34-7.33 µg/m 3 ), and concentrations were high in April, May, June, and October. In contrast, endotoxin was mainly included in coarse particles (0.0010-0.0246 EU/m 3 ), and concentrations were high in September (third week), October (first, second, and fourth weeks), February (fourth week), and July (first week). The results of a Poisson regression analysis indicated that endotoxin (in fine and coarse particles alike) was a significant factor for ED visits related to asthma in children, even after adjusting for meteorological factors, i.e., temperature, relative humidity, and wind speed. However, there was no association between environmental factors and ED visits for asthma in adults. These results suggest that endotoxin in outdoor air is significantly associated with an increased risk of asthma exacerbation in children.

The present paper reports the first size-resolved element measurements in the PM 2.5 fraction collected throughout 2016 in the Iasi urban area in north-eastern Romania. Concentrations of water-soluble elements (Ag, Al, As, B, Ba, Be, Bi, Cd, Co, Cu, Cr, Fe, Ga, Mg, Mn, Mo, Ni, Pb, Rb, Se, Sr, Te, Ti, U, V, Zn) were determined using inductively coupled plasma mass spectrometry. Several water-soluble heavy metals (Al, Fe, Zn, As, Cr, Pb) exhibit clear seasonal patterns with maxima over the cold season and minima over the warm season. Elements as Al, Fe, Mg, Zn, Ni, Mn, and Cu present the highest levels in the PM 2.5 fraction, indicating significant contributions from soil-dust resuspension or brake lining and tires. Clear fine mode size-dependent distributions were observed for anthropogenic source-origin elements (Pb, Zn, Cd, V, etc.) due to an acidity-driven metals dissolution process. Positive matrix factorization, concentration weighted trajectory and bivariate polar plot analyses were applied to the entire PM 2.5 database. Based on relative concentrations of various elements, five factors associated with specific sources were identified. The most important contributions to the total PM 2.5 mass concentration (during the total period) come from secondary formation of the ammonium sulfate form (~44%) and from nitrate (~37%). Resuspended dust accounts for a contribution of about 16%, while biomass burning mixed with NaCl salt/sea-salt sources contribute as much as ~3%. Traffic and industrial sources seem to yield little contribution (<0.05%). An assessment investigation of non-carcinogenic and carcinogenic health risks revealed water-soluble arsenic and chromium (VI) as elements with the largest incremental carcinogenic risks. Both metals have traffic and industrial related sources and therefore it is believed that in the future, at the local/regional level, these sources should receive attention by implementing appropriate emission control measures., (Copyright © 2019 The Authors. Published by Elsevier B.V. All rights reserved.)

This study systematically reviewed all the cohort studies investigating the relationship between long-term exposure to PM 2.5 and any health outcome until February 2018. We searched ISI Web of Knowledge, Pubmed, and Scopus databases for peer-reviewed journal research articles published in English. We only extracted the results of the single-pollutant main analysis of each study, excluding the effect modifications and sensitivity analyses. Out of the initial 9523 articles, 203 articles were ultimately included for analysis. Based on the different characteristics of studies such as study design, outcome, exposure assessment method, and statistical model, we calculated the number and relative frequency of analyses with statistically significant and insignificant results. Most of the studies were prospective (84.8%), assessed both genders (66.5%), and focused on a specific age range (86.8%). Most of the articles (78.1%) had used modeling techniques for exposure assessment of cohorts' participants. Among the total of 317 health outcomes, the most investigated outcomes include mortality due to cardiovascular disease (6.19%), all causes (5.48%), lung cancer (4.00%), ischemic heart disease (3.50%), and non-accidental causes (3.50%). The percentage of analyses with statistically significant results were higher among studies that used prospective design, mortality as the outcome, fixed stations as exposure assessment method, hazard ratio as risk measure, and no covariate adjustment. We can somehow conclude that the choice of right characteristics for cohort studies can make a difference in their results.

The primary objective of the present study was to evaluate the concentrations and short and long-term excess mortality attributed to PM 2.5 , NO 2 , and O 3 observed in ambient air of Ahvaz during March 2014 to March 2017 period using the AirQ + software developed by the World Health Organization (WHO), which is updated in 2016 by WHO European Centre for Environment and Health. The hourly concentrations of PM 2.5 , O 3 , and NO 2 measured at different regulatory monitoring network stations in Ahvaz city were obtained from the Department of Environment (DOE) of the city. Then, for various air quality monitoring stations, the 24-h average concentration of PM 2.5 , 1-h average of NO 2 concentration, and maximum daily 8-h O 3 concentrations were calculated using Excel 2010 software. When the maximum daily 8-h ozone means exceeding the value of 35, it was subtracted from 35 to calculate SOMO35 indicator for modeling. Validation of air quality data was performed according to the Aphekom and WHO's methodologies for health impact assessment of air pollution. Year-specific city population and baseline incidence of the health outcomes were obtained. The three-year averages of PM 2.5 , NO 2 , and O 3 concentrations were 68.95 (±39.86) μg/m 3 , 135.90 (±47.82) μg/m 3 , and 38.63 (±12.83) parts-per-billion-volume (ppbv), respectively. SOMO35 values of ozone were 6596.66, 3411.78, and 470.88 ppbv in 2014-2015, 2015-2016, and 2016-2017 years, respectively. The AP and number of natural deaths due to NO 2 were higher than PM 2.5 except the last year (2016-2017), causing about 39.18%, 40.73%, and 14.39% of deaths within the first, the second, and the third year, respectively. However, for the last year, the natural mortality for PM 2.5 was higher than NO 2 (34.46% versus 14.39%). The total number of natural mortality caused by PM 2.5 and NO 2 in all years was 4061 and 4391, respectively. A significant number of deaths was estimated to be attributed to the given air pollutants. It can be concluded that by designing and implementing air pollution control strategies and actions, both health effects and economic losses will be prevented., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Association between short-term exposure to fine particulate matter (PM 2.5 ) and mortality or morbidity varies geographically, and this variation could be due to different chemical composition affected by local sources. However, there have been only a few Asian studies possibly due to limited monitoring data. Using nationwide regulatory monitoring data of PM 2.5 chemical components in South Korea, we aimed to compare the associations between daily exposure to PM 2.5 components and mortality across six major cities. We obtained daily 24-h concentrations of PM 2.5 and 11 PM 2.5 components measured from 2013 to 2015 at single sites located in residential areas. We used death certificate data to compute the daily counts of nonaccidental, cardiovascular, and respiratory deaths. Using the generalized additive model, we estimated relative risks of daily mortality for an interquartile range increase in each pollutant concentration, while controlling for a longer-term time trend and meteorology. While elemental carbon was consistently associated with nonaccidental mortality across all cities, nickel and vanadium were strongly associated with respiratory or cardiovascular mortality in Busan and Ulsan, two large port cities. Our study shows that PM 2.5 components responsible for PM 2.5 -associated mortality differed across cities depending on the dominant pollution sources, such as traffic and oil combustion.

Fine particulate matter (PM 2.5 ) is an important air pollutant due to its adverse health effects. Vehicle emissions make a large contribution to particle concentrations in urban areas. Exposure to particles especially near roadways increases the risk of public health problems. Planting vegetation might be used to capture the fine particles at the roadside, which can lower the health risks for the urban population. Istanbul is the most populous city in Turkey, where the number of non-electric cars is increasing rapidly, resulting in decreasing air quality, especially at the roadsides. Recent studies show that cardiovascular, respiratory and total non-accidental mortality is increasing with short-term exposure to outdoor air pollution in Istanbul. In this study, roadside trees were investigated for the mitigation effect on vehicle-related PM 2.5 and heavy metal (HM). Cupressus sempervirens (Mediterranean Cypress trees) were planted in three different cases (i.e., no trees-C1, trees with gaps-C2 and thick trees with no gaps-C3) at the study site. Location of the site is on a dense-traffic roadside in Istanbul, where thousands of people are living, working and walking through two sides of this road. PM 2.5 samples and tree leaves were examined in the performed experiments. C2 and C3 showed the importance of roadside tree plantation by reducing the exposure to significantly low levels. Roadside PM 2.5 concentrations were reduced by 17% in C3, equivalent to urban background levels in the city. Maximum removal of HMs is observed in nickel from 26.4 ± 7.8 to 7.5 ± 2.4 μg m -3 . Pedestrian exposure is calculated with the measured data in three experiments and exposure is significantly reduced (e.g., >50% for cadmium and lead exposure) in experiment C3. In conclusion, three experiments showed that Mediterranean Cypress trees significantly decreased particle pollution at roadsides in Istanbul., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Levels, compositions, sources, and cancer risks of fine particle (PM 2.5 )-bound PAHs were investigated at an urban site of Wuhan, Central China. Totally 115 PM 2.5 samples collected during four seasons from 2014 to 2015 were analyzed for 16 USEPA priority PAHs. The annual average of PM 2.5 and total PAHs were 106 ± 41.7 μg m -3 and 25.1 ± 19.4 ng m -3 , respectively. The seasonal levels of PM 2.5 and PAHs varied in a similar trend, with the highest concentrations in winter and the lowest in summer. PM 2.5 -bound PAHs under different pollution level was discussed and the highest average PAH levels were found at a moderate (115-150 μg m -3 ) air quality level. Three sources including coal combustion and biomass burning, petrogenic source, and vehicle emissions were extracted and quantified by the positive matrix factorization (PMF) model, accounting for 22.7 ± 21.3%, 34.4 ± 29.0% and 42.9 ± 31.3% of the total PAHs, respectively. The potential source contribution function (PSCF) and the concentration-weighted trajectory (CWT) were combined to explore the geographic origins of PAHs. The spatial distributions of coal combustion and biomass burning, petrogenic source, and vehicle emissions were well correlated with medium molecular weight (MMW), low molecular weight (LMW) and high molecular weight (HMW) PAHs, respectively. Results of PSCF and CWT indicated that the long-distance transport form north of Wuhan as far as northern and eastern of China was higher than that from the southern China while the contribution of local areas was higher than those from the long-range transport. The overall lifetime lung cancer risk (LLCR) via inhalation exposure to PM 2.5 -bound PAHs was estimated as 3.03 × 10 -4 , with vehicle emissions contributed 57.1% (1.6 × 10 -4 ) to the total risk on average, followed by coal combustion and biomass burning (31.0%, 9.6 × 10 -5 ), and petrogenic source (11.9%, 3.6 × 10 -5 )., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The Korea Simulation Exposure Model for fine particulate matter (PM 2.5 ) (KoSEM-PM) was developed to estimate population PM 2.5 exposure in Korea. The data were acquired based on 59,945 min of the actual microenvironmental PM 2.5 measurements and on the time⁻activity patterns of 8072 residents of Seoul. The aims of the study were to estimate daily PM 2.5 exposure of Seoul population, and to determine the characteristics of a high exposure group. KoSEM-PM estimated population exposures by applying the PM 2.5 distribution to the matching time⁻activity patterns at 10-min intervals. The mean personal PM 2.5 exposure level of the surveyed subjects in Seoul was 26.0 ± 2.7 µg/m³ (range: 21.0⁻40.2 µg/m³) in summer. Factors significantly associated with high exposure included day of the week, age, industry sector, job type, and working hours. Individuals surveyed on Saturdays were more likely to be in the high exposure group than those surveyed on weekdays and Sundays. Younger, non-office-working individuals with longer working hours were more likely to be in the high exposure group. KoSEM-PM could be a useful tool to estimate population exposure levels to other region in Korea; to expand its use, microenvironmental measurements are required for other region in Korea.

Fine particle (PM 2.5 )-related lung damage has been reported in most studies regarding environmental or personal PM 2.5 concentrations. To assess effects of personal PM 2.5 exposures on lung function, we recruited 20 postgraduate students and estimated the individual doses of inhaled PM 2.5 based on their microenvironmetal PM 2.5 concentrations, time-activity patterns and refereed inhalation rates. During the period of seven consecutive days in each of the four seasons, we repeatedly measured the daily lung function parameters and airway inflammation makers such as fractional exhaled nitric oxide (FeNO) as well as systemic inflammation markers including interleukin-1β on the final day. The high individual dose (median (IQR)) of inhaled PM 2.5 was 957 (948) μg/day. We observed a maximum FeNO increase (9.1% (95%CI: 2.2-15.5)) at lag 0 day, a maximum decrease of maximum voluntary ventilation (11.8% (95% CI: 4.6-19.0)) at lag 5 day and a maximum interleukin-1β increase (103% (95% CI: 47-159)) at lag 2 day for an interquartile range increase in the individual dose of inhaled PM 2.5 during the four seasons. Short-term exposure to PM 2.5 assessed by the individual dose of inhaled PM 2.5 was associated with higher airway and systemic inflammation and reduced lung function. Further studies are needed to understand better underlying mechanisms of lung damage following acute exposure to PM 2.5., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

To determine the levels of endotoxin, which is a major component of outer membrane of Gram-negative bacteria, and protein in the atmosphere in Sasebo, Japan, we measured these biological materials in fine (aerodynamic diameter ≤2.5 µm) and coarse (≥2.5 µm) particles collected for 81 weeks (September 2014 to May 2016). The monthly concentrations (i.e., the mean value of weekly concentrations for each month) of endotoxin were higher in coarse particles than in fine particles. Fluctuations in monthly endotoxin concentrations were large in both fine (0.0005-0.0208 EU/m 3 ) and coarse (0.0032-0.1164 EU/m 3 ) particles. Furthermore, the endotoxin concentrations in coarse particles were highest in October 2014 and 2015 as well as September 2014 (0.0407-0.1164 EU/m 3 ). However, the monthly protein concentrations were higher in fine particles than in coarse particles. Compared to the endotoxin concentrations, the fluctuations in the monthly protein concentrations were smaller in both coarse and fine particles. To our knowledge, this study is the first to report long-term atmospheric concentrations of endotoxin and protein in Japan. Since the endotoxin concentrations in coarse particles were positively associated with the concentrations of Na + and Cl - , it suggests the involvement of Gram-negative bacteria from seawater to the endotoxin levels in the atmosphere. For fine particles, the protein concentrations were positively associated with the concentrations of particles, NO 3 - and SO 4 2- . These results suggest that combustion of organic materials, such as biomass burning, may be a contributor to atmospheric protein during this study period.

Purpose of Review: Epidemiological studies of health effects of long-term exposure to outdoor air pollution rely on different exposure assessment methods. This review discusses widely used methods with a special focus on new developments., Recent Findings: New data and study designs have been applied, including satellite measurements of fine particles and nitrogen dioxide (NO 2 ). The methods to apply satellite data for epidemiological studies are improving rapidly and have already contributed significantly to national-, continental- and global-scale models. Spatiotemporal models have been developed allowing more detailed temporal resolution compared to spatial models. The development of hybrid models combining dispersion models, satellite observations, land use and surface monitoring has improved models substantially. Mobile monitoring designs to develop models for long-term UFP exposure have been conducted. Methods to assess long-term exposure to outdoor air pollution have improved significantly over the past decade. Application of satellite data and mobile monitoring designs is promising new methods.

Many studies have been conducted focusing on the contribution of land emission sources to PM 2.5 in China; however, little attention had been paid to other contributions, especially the secondary contributions from shipping emissions to atmospheric PM 2.5 . In this study, a combined source apportionment approach, including principle component analysis (PCA) and WRF-CMAQ simulation, was applied to identify both primary and secondary contributions from ships to atmospheric PM 2.5 . An intensive PM 2.5 observation was conducted from April 2014 to January 2015 in Qinhuangdao, which was close to the largest energy output port of China. The chemical components analysis results showed that the primary component was the major contributor to PM 2.5 , with proportions of 48.3%, 48.9%, 55.1% and 55.4% in spring, summer, autumn and winter, respectively. The secondary component contributed higher fractions in summer (48.2%) and winter (36.8%), but had lower percentages in spring (30.1%) and autumn (32.7%). The hybrid source apportionment results indicated that the secondary contribution (SC) of shipping emissions to PM 2.5 could not be ignored. The annual average SC was 2.7%, which was comparable to the primary contribution (2.9%). The SC was higher in summer (5.3%), but lower in winter (1.1%). The primary contributions to atmospheric PM 2.5 were 3.0%, 2.5%, 3.4% and 2.7% in spring, summer, autumn and winter, respectively. As for the detailed chemical components, the contributions of shipping emissions were 2.3%, 0.5%, 0.1%, 1.0%, 1.7% and 0.1% to elements & sea salt, primary organic aerosol (POA), element carbon (EC), nitrate, sulfate and secondary organic carbon (SOA), respectively. The results of this study will further the understanding of the implications of shipping emissions in PM 2.5 pollution., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

This study systemically investigated the ambient PM 2.5 (n=108) with comprehensive analyses of the chemical composition, identification of the potential contributors, and estimation of the resultant respiratory physician visits in the residential regions near energy-consuming and high-polluting industries in central Taiwan. The positive matrix fraction (PMF) model with chemical profiles of trace metals, water-soluble ions, and organic/elemental carbons (OC/EC) was applied to quantify the potential sources of PM 2.5 . The influences of local sources were also explored using the conditional probability function (CPF). Associations between the daily PM 2.5 concentration and the risk of respiratory physician visits for the elderly (≥65years of age) were estimated using time-series analysis. A seasonal variation, with higher concentrations of PM 2.5 , metals (As, Cd, Sb, and Pb), OC/EC and ions (i.e., NO 3- , SO 4 2- and NH 4 + ) in the winter than in the spring and summer, was observed. Overall, an increase of 10μgm -3 in the same-day PM 2.5 was associated with an ~2% (95% CI: 1.5%-2.5%) increase in respiratory physician visits. Considering the health benefits of an effective reduction, we suggest that the emission from coal combustion (23.5%), iron ore and steel industry (17.1%), and non-ferrous metallurgy (14.4%), accounting for ~70% of the primary PM 2.5 in the winter are prioritized to control., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Increased ambient concentration of particulate matters are considered as one of major causes for increased prevalence or exacerbation of asthma or asthma like symptoms. Recently, possible temporal variation in risks of PM on mortality has been suggested. We investigated short-term effect of both PM 10 and PM 2.5 on asthma hospitalization, and assessed temporal variation of PM risks in Seoul, Korea, 2003-2011. Generalized additive model was used to estimate PM risks on asthma hospitalization with consideration by long-term trend, influenza epidemic, day of week, meteorological factors. To assess temporal variation of PM risks, year-round PM risks were estimated. Stratified analysis by season and age-group were also conducted. Estimated RRs of PM on asthma hospitalization by an increase of 10㎍/㎥were 1.0084 (95% CI: 1.0041-1.0127) and 1.0156 (95% CI: 1.0055-1.0259) respectively with 7-days lag periods (lag06). PM 2.5 had stronger effect than PM 10 for all age group. Elderly group was most affected by PM. For the analysis of temporal variation of PM risks, we found increasing trend in total population and the elderly group. In the season-specific analysis, we also found increasing trend in winter for PM 10 , and in spring for PM 2.5 . PM 10 and PM 2.5 has adverse effect on asthma hospitalization with evidence suggesting temporal variation in PM risks. Further research will be needed to confirm the temporal variation of PM risk on asthma hospitalization, and to identify casual factors affecting this temporal variation. This study results could be evidentiary materials for establishing valid public health policies to reduce health burden or economic burden of asthma., (Copyright © 2017. Published by Elsevier Inc.)

The relationship between the fine particles emitted after desulfurization and gypsum crystals in the desulfurization slurry was investigated, and the crystallization characteristics varying with the operation parameters and compositions of the desulfurization slurry were discussed. The results showed that the fine particles generated during the desulfurization process were closely related to the crystal characteristics in the desulfurization slurry by comparison of their morphology and elements. With the higher proportion of fine crystals in the desulfurization slurry, the number concentration of fine particles after desulfurization was increased and their particle sizes were smaller, indicating that the optimization of gypsum crystallization was beneficial for the reduction of the fine particle emission. The lower pH value and an optimal temperature of the desulfurization slurry were beneficial to restrain the generation of fine crystals in the desulfurization slurry. In addition, the higher concentrations of the Fe 3+ ions and the F - ions in the desulfurization slurry both promoted the generation of fine crystals with corresponding change of the morphology and the effect of the Fe 3+ ions was more obvious. With the application of the desulfurization synergist additive, it was beneficial for the inhibition of fine crystals while the thinner crystals were generated., (Copyright © 2016. Published by Elsevier B.V.)

We estimated the short-term effects of particulate matter (PM) pollution with aerodynamic diameters ≤2.5 μm (PM 2.5 ) and between 2.5 and 10 μm (PM c ) on hospital outpatient visits due to overall and specific respiratory diseases, as well as the associated morbidity burden in Dongguan, a subtropical city in South China. A time-series model with quasi-Poisson link was used to examine the association between PM pollution and morbidities from respiratory diseases, COPD, asthma and pneumonia in Dongguan during 2013-2015. We further estimated the morbidity burden (population attributable fraction and attributable morbidity) due to ambient PM pollution. A total of 44,801 hospital outpatient visits for respiratory diseases were recorded during the study period. Both PM 2.5 and PM c were found to be significantly associated with morbidity of overall respiratory diseases, COPD, and asthma. An IQR (interquartile range) increase in PM 2.5 at lag 03 day was associated with 15.41% (95% CI: 10.99%, 20.01%) increase in respiratory morbidity, and each IQR increase in PM c at lag 03 corresponded to 7.24% (95% CI: 4.25%, 10.32%) increase in respiratory morbidity. We did not find significant effects of PM 2.5 and PM c on pneumonia. Using WHO's guideline (25 μg/m 3 ) as reference concentration, about 8.32% (95% CI: 5.90%, 10.86%) of respiratory morbidity (3727, 95% CI: 2642, 4867, in morbidity number) were estimated to be attributed to PM 2.5 , and 0.86% (95% CI: 0.50%, 1.23%) of respiratory morbidity, representing 385 (95% CI: 225, 551) hospital outpatient visits, could be attributed to coarse particulate pollutant. Our study suggests that both fine and coarse particulate pollutants are an important trigger of hospital outpatient visits for respiratory diseases, and account for substantial respiratory morbidity in Dongguan, China., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

This study investigates PM 2.5 -bound PAHs for rural sites (Dacheng and Fangyuan) positioned close to heavy air-polluting industries in Changhua County, central Taiwan. A total of 113 PM 2.5 samples with 22 PAHs collected from 2014 to 2015 were analyzed, and Positive Matrix Factorization (PMF) and diagnostic ratios of PAHs were applied to quantify potential PAH sources. The influences of local and regional sources were also explored using the conditional probability function (CPF) and potential source contribution function (PSCF) with PMF-modeled results, respectively. Annual mean concentrations of total PAHs were 2.91 ± 1.34 and 3.04 ± 1.40 ng/m 3 for Dacheng and Fangyuan, respectively, and their corresponding BaP eq were measured at 0.534 ± 0.255 and 0.563 ± 0.273 ng/m 3 in concentration. Seasonal variations with higher PAHs found for the winter than for the spring and summer were observed for both sites. The lifetime excess cancer risk (ECR) from inhalation exposure to PAHs was recorded as 4.7 × 10 -5 overall. Potential sources of PM 2.5 -bound PAHs include unburned petroleum and traffic emissions (42%), steel industry and coal combustion (31%), and petroleum and oil burning (27%), and unburned petroleum and traffic emission could contribute the highest ECR (2.4 × 10 -5 ). The CPF results show that directional apportionment patterns were consistent with the actual locations of local PAH sources. The PSCF results indicate that mainly northeastern regions of China have contributed elevated PM 2.5 -bound PAHs from long-range transports., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

This study investigated seasonal variations in PM10 and PM2.5 mass and associated trace metal concentrations in a residential area in proximity to the crude oil refinery plants and industrial parks of central Taiwan. Particle measurements were conducted during winter, spring and summer in 2013 and 2014. Twenty-six trace metals in PM10 and PM2.5 were analyzed using ICP-MS. Multiple approaches of the backward trajectory model, enrichment factor (EF), Lanthanum enrichment and positive matrix fraction (PMF) were used to identify potential sources of particulate metals. Mean concentrations of PM10 in winter, spring and summer were 76.4 ± 22.6, 33.2 ± 9.9 and 37.4 ± 17.0 μg m(-3), respectively, while mean levels of PM2.5 in winter, spring and summer were 47.8 ± 20.0, 23.9 ± 11.2 and 16.3 ± 8.2 μg m(-3), respectively. The concentrations of carcinogenic metals (Ni, As and adjusted Cr(VI)) in PM10 and PM2.5 exceeded the guideline limits published by WHO. The result of EF analysis confirmed that Mo, Sb, Cd, Zn, Mg, Cr, As, Pb, Cu, Ni and V were attributable to anthropogenic emission. PMF analysis demonstrated that trace metals in PM10 and PM2.5 were from the similar sources, such as coal combustion, oil combustion and traffic-related emission, except for soil dust and crustal element emissions only observed in PM10 and secondary aluminum smelter only observed in PM2.5. Considering health-related particulate metals, the traffic-related emission and coal combustion for PM10 and PM2.5, respectively, are important to control for reducing potential carcinogenic risk. The results could aid efforts to clarify the impact of source-specific origins on human health., (Copyright © 2015 Elsevier B.V. All rights reserved.)

The primary objective of the present study was to evaluate the concentrations and short and long-term excess mortality attributed to PM 2.5 , NO 2 , and O 3 observed in ambient air of Ahvaz during March 2014 to March 2017 period using the AirQ + software developed by the World Health Organization (WHO), which is updated in 2016 by WHO European Centre for Environment and Health. The hourly concentrations of PM 2.5 , O 3 , and NO 2 measured at different regulatory monitoring network stations in Ahvaz city were obtained from the Department of Environment (DOE) of the city. Then, for various air quality monitoring stations, the 24-h average concentration of PM 2.5 , 1-h average of NO 2 concentration, and maximum daily 8-h O 3 concentrations were calculated using Excel 2010 software. When the maximum daily 8-h ozone means exceeding the value of 35, it was subtracted from 35 to calculate SOMO35 indicator for modeling. Validation of air quality data was performed according to the Aphekom and WHO's methodologies for health impact assessment of air pollution. Year-specific city population and baseline incidence of the health outcomes were obtained. The three-year averages of PM 2.5 , NO 2 , and O 3 concentrations were 68.95 (±39.86) μg/m3, 135.90 (±47.82) μg/m3, and 38.63 (±12.83) parts-per-billion-volume (ppbv), respectively. SOMO35 values of ozone were 6596.66, 3411.78, and 470.88 ppbv in 2014–2015, 2015–2016, and 2016-2017 years, respectively. The AP and number of natural deaths due to NO 2 were higher than PM 2.5 except the last year (2016–2017), causing about 39.18%, 40.73%, and 14.39% of deaths within the first, the second, and the third year, respectively. However, for the last year, the natural mortality for PM 2.5 was higher than NO 2 (34.46% versus 14.39%). The total number of natural mortality caused by PM 2.5 and NO 2 in all years was 4061 and 4391, respectively. A significant number of deaths was estimated to be attributed to the given air pollutants. It can be concluded that by designing and implementing air pollution control strategies and actions, both health effects and economic losses will be prevented. • Attributed short and long term morbidity for PM 2.5 , NO 2 and O 3 was assessed. • Year-specific city population and baseline incidence of the health outcomes were obtained. • Number of death cases for IHD, COPD, lung cancer, and ALRI attributed to PM2.5 was estimated. • The attributable health effects of ozone were low and negligible. [ABSTRACT FROM AUTHOR]

Cooking is an important source of particulate matters in Chinese residences. In this study, 11 dishes of double cooked pork slices and 11 dishes of stir-fried chicken dices with hot chili were finished for 70 mins. Real-time concentrations of ultrafine and fine particles are monitored during and after cooking. The source strength was calculated based on the mass balance equation. The ultrafine and the fine particle source strength is estimated at 2.42~2.61×10 11 #/s and 0.120~0.147 mg/s, respectively, during the cooking period. The source strength may be further applied for evaluating indoor ultrafine particle level and exposure of ultrafine and fine particle originated from Chinese cooking. [ABSTRACT FROM AUTHOR]

The influence of long-range transport (LRT) of air pollutants on neighboring regions and countries has been documented. The magnitude of LRT aerosols and related constituents can misdirect control strategies for local air quality management. In this study, we aimed to quantify PM 2.5 (diameter less than 2.5 μm, PM 2.5) and associated metals derived from local sources and LRT in different geographic locations in Taiwan using advanced receptor models. We collected daily PM 2.5 samples (n = ∼1000) and analyzed 28 metals every three days from 2016 to 2018 in the northern, central-south, eastern, and southern areas of Taiwan. We first used a machine learning technique with a cluster algorithm coupled with a backward trajectory to classify local, regional, and LRT-related aerosols. We then quantified the source contributions with a positive matrix factorization (PMF) model for Taiwan weighted by region-specific populations. The northern and eastern regions were found to be more vulnerable to LRT-related PM 2.5 and metals than the central-south and southern regions in Taiwan. The LRT increased Pb and As concentrations by 90–200% and ∼40% in the northern and central-south regions. Ambient PM 2.5 -metals mainly originated from local traffic-related emissions in the northern, central-south, and southern regions, whereas oil combustion was the primary source of PM 2.5 -metals in the eastern region. By subtracting the influence from the LRT, the contributions of domestic emission sources to ambient PM 2.5 metals in Taiwan were 35% from traffic-related emission, 17% from non-ferrous metallurgy, 13% from iron ore and steel factories, 12% from coal combustion, 12% from oil combustion, 10% from incinerator emissions, and <1% from cement manufacturing emissions. This study proposed an advanced method for refining local source contributions to ambient PM 2.5 metals in Taiwan, which provides useful information on regional control strategies. [Display omitted] • To quantify PM 2.5 -metals derived from domestic sources in different geographic locations. • A machine learning technique with a cluster algorithm coupled with a backward trajectory was used. • LRT aerosols remarkably increased PM 2.5 in Taipei and Hualien. • The LRT increased Pb and As by 90–200% in the northern regions. • Traffic-related emissions were the most important sources of PM 2.5 -metals in Taiwan. [ABSTRACT FROM AUTHOR]

An observational study on trace gases and PM 2.5 was conducted at three sites in and around Beijing, during the Olympic season from 2007 to 2009. Air quality improved significantly during the Olympic Games due to the special emission control measures. However, concentrations of the primary pollutants and PM were found to have risen significantly after the Games. Although the major O 3 precursors (NO x and VOCs) were well controlled during the Olympic season, O 3 was still found to be the highest in 2008, based on the data of ground-based observation. All this information suggests that while control of regional emissions for the Beijing Olympic Games did improved the air quality in Beijing, more efforts will be needed for the continuous improvement of regional air quality, especially for significant reductions of O 3 and fine particulate pollution, and not only in Beijing, but also in the Beijing-Tianjin-Hebei region. [ABSTRACT FROM AUTHOR]