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This paper attempts to accurately evaluate the contribution of construction dust to China's PM2.5 emissions in order to increase environmental authorities' efficiency at managing emissions in urban environments. The study was conducted in the main urban area of Chongqing. Three typical construction sites were designated as the study area, where PM2.5 emission concentration data were collected through field investigation and processed by an AERMOD model. PM2.5 emission intensity and annual average PM2.5 emissions from construction dust in the study area were also ascertained. The results showed that the PM2.5 emission intensity and annual average PM2.5 emissions from construction dust in the study area were 0.0059 kg/m² month and 6220.5 t, respectively. The PM2.5 emission concentration of construction dust showed a negative correlation with real-time wind speed. This paper's conclusions can serve as a reference for related departments that make decisions on PM2.5 emission management. [ABSTRACT FROM AUTHOR]

The Sichuan-Chongqing region is the leader and growth pole of economic development in western China. With the rapid development of economy and unique geographical environment, high concentration of sulfur dioxide air pollution has existed for a long time in Sichuan-Chongqing area. Based on 10 years of remote sensing data, this paper studies the temporal and spatial distribution characteristics, stability, and influencing factors of sulfur dioxide in this area. Based on potential sources, the impact of surrounding areas on sulfur dioxide in Sichuan and Chongqing is analyzed. The results shows that the spatial distribution of sulfur dioxide in the Sichuan-Chongqing region is higher in the southeast and lower in the west. The Midwest region has low fluctuation and good stability. The time distribution shows obvious seasonal regularity. The concentration of sulfur dioxide is affected by socio-economic factors and natural factors. In this study, it is found that the distribution of sulfur dioxide is closely related to PM2.5, which provides an important reference for the comprehensive management of air pollution. The OMI data effectively reflects the distribution and change of atmospheric sulfur dioxide in the Sichuan-Chongqing region, and provides certain ideas for air pollution control in the Sichuan-Chongqing region and other regions in China. [ABSTRACT FROM AUTHOR]

Background: Preterm birth (PTB) is an important predictor of perinatal morbidity and mortality. Previous researches have reported a correlation between air pollution and an increased risk of preterm birth. However, the specific relationship between short-term and long-term exposure to carbon monoxide (CO) and preterm birth remains less explored. Methods: A population-based study was conducted among 515,498 pregnant women in Chongqing, China, to assess short-term and long-term effects of CO on preterm and very preterm births. Generalized additive models (GAM) were applied to evaluate short-term effects, and exposure-response correlation curves were plotted after adjusting for confounding factors. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated using COX proportional hazard models to estimate the long-term effect. Results: The daily incidence of preterm and very preterm birth was 5.99% and 0.41%, respectively. A positive association between a 100 µg/m³ increase in CO and PTB was observed at lag 0–3 days and 12–21 days, with a maximum relative risk (RR) of 1.021(95%CI: 1.001–1.043). The exposure-response curves (lag 0 day) revealed a rapid increase in PTB due to CO. Regarding long-term exposure, positive associations were found between a 100 µg/m3 CO increase for each trimester(Model 2 for trimester 1: HR = 1.054, 95%CI: 1.048–1.060; Model 2 for trimester 2: HR = 1.066, 95%CI: 1.060–1.073; Model 2 for trimester 3: HR = 1.007, 95%CI: 1.001–1.013; Model 2 for entire pregnancy: HR = 1.080, 95%CI: 1.073–1.088) and higher HRs of very preterm birth. Multiplicative interactions between air pollution and CO on the risk of preterm and very preterm birth were detected (P- interaction<0.05). Conclusions: Our findings suggest that short-term exposure to low levels of CO may have protective effects against preterm birth, while long-term exposure to low concentrations of CO may reduce the risk of both preterm and very preterm birth. Moreover, our study indicated that very preterm birth is more susceptible to the influence of long-term exposure to CO during pregnancy, with acute CO exposure exhibiting a greater impact on preterm birth. It is imperative for pregnant women to minimize exposure to ambient air pollutants. [ABSTRACT FROM AUTHOR]

Emerging research findings suggest that airborne particulate matter might be a risk factor for gestational diabetes mellitus (GDM). However, the concentration–response relationships and the susceptible time windows for different types of particulate matter may vary. In this retrospective analysis, we employ a novel robust approach to assess the crucial time windows regarding the prevalence of GDM and to distinguish the susceptibility of three GDM subtypes to air pollution exposure. This study included 16,303 pregnant women who received routine antenatal care in 2018–2021 at the Maternal and Child Health Hospital in Chongqing, China. In total, 2482 women (15.2%) were diagnosed with GDM. We assessed the individual daily average exposure to air pollution, including PM2.5, PM10, O3, NO2, SO2, and CO based on the volunteers' addresses. We used high-accuracy gridded air pollution data generated by machine learning models to assess particulate matter per maternal exposure levels. We further analyzed the association of pre-pregnancy, early, and mid-pregnancy exposure to environmental pollutants using a generalized additive model (GAM) and distributed lag nonlinear models (DLNMs) to analyze the association between exposure at specific gestational weeks and the risk of GDM. We observed that, during the first trimester, per IQR increases for PM10 and PM2.5 exposure were associated with increased GDM risk (PM10: OR = 1.19, 95%CI: 1.07~1.33; PM2.5: OR = 1.32, 95%CI: 1.15~1.50) and isolated post-load hyperglycemia (GDM-IPH) risk (PM10: OR = 1.23, 95%CI: 1.09~1.39; PM2.5: OR = 1.38, 95%CI: 1.18~1.61). Second-trimester O3 exposure was positively correlated with the associated risk of GDM, while pre-pregnancy and first-trimester exposure was negatively associated with the risk of GDM-IPH. Exposure to SO2 in the second trimester was negatively associated with the risk of GDM-IPH. However, there were no observed associations between NO2 and CO exposure and the risk of GDM and its subgroups. Our results suggest that maternal exposure to particulate matter during early pregnancy and exposure to O3 in the second trimester might increase the risk of GDM, and GDM-IPH is the susceptible GDM subtype to airborne particulate matter exposure. [ABSTRACT FROM AUTHOR]

Clarifying the spatiotemporal distribution and impact mechanism of pollution is the prerequisite for megacities to formulate relevant air pollution prevention and control measures and achieve carbon neutrality goals. Chongqing is one of the dual-core key megacities in Cheng-Yu region and as a typical mountain-city in China, environmental problems are complex and sensitive. This research aims to investigate the exceeding standard levels and spatio-temporal evolution of criteria pollutants between 2014 and 2020. The results indicated that PM10, PM2.5, CO and SO2 were decreased significantly by 45.91%, 52.86%, 38.89% and 66.67%, respectively. Conversely, the concentration of pollutant O3 present a fluctuating growth and found a "seesaw" phenomenon between it and PM. Furthermore, PM and O3 are highest in winter and summer, respectively. SO2, NO2, CO, and PM showed a "U-shaped", and O3 showed an inverted "U-shaped" seasonal variation. PM and O3 concentrations are still far behind the WHO, 2021AQGs standards. Significant spatial heterogeneity was observed in air pollution distribution. These results are of great significance for Chongqing to achieve "double control and double reduction" of PM2.5 and O3 pollution, and formulate a regional carbon peaking roadmap under climate coordination. Besides, it can provide an important platform for exploring air pollution in typical terrain around the world and provide references for related epidemiological research. Implications: Chongqing is one of the dual-core key megacities in Cheng-Yu region and as a typical mountain city, environmental problems are complex and sensitive. Under the background of the "14th Five-Year Plan", the construction of the "Cheng-Yu Dual-City Economic Circle" and the "Dual-Carbon" goal, this article comprehensively discussed the annual and seasonal excess levels and spatiotemporal evolution of pollutants under the multiple policy and the newest international standards (WHO,2021AQG) backgrounds from 2014 to 2020 in Chongqing. Furthermore, suggestions and measures related to the collaborative management of pollutants were discussed. Finally, limitations and recommendations were also put forward. Clarifying the spatiotemporal distribution and impact mechanism of pollution is the prerequisite for cities to formulate relevant air pollution control measures and achieve carbon neutrality goals. This study is of great significance for Chongqing to achieve "double control and double reduction" of PM2.5 and O3 pollution, study and formulate a regional carbon peaking roadmap under climate coordination and an action plan for sustained improvement of air quality. In addition, this research can advanced our understanding of air pollution in complex terrain. Furthermore, it also promote the construction of the China national strategic Cheng-Yu economic circle and build a beautiful west. Moreover, it provides scientific insights for local policymakers to guide smart urban planning, industrial layout, energy structure, and transportation planning to improve air quality throughout the Cheng-Yu region. Finally, this is also conducive to future scientific research in other regions of China, and even megacities with complex terrain in the world. [ABSTRACT FROM AUTHOR]

Purpose ? The purpose of this paper is to trace the heavy reliance of coal as an energy source in the city of Chongqing and the serious impact this has had on the air quality together with the municipal authority's responses. Design/methodology/approach ? It provides a factual description of the coal centred strategy and the heavy reliance on secondary industry output to fuel Chongqing's growth which has in turn brought about air pollution and acid rain. Findings ? The authorities are now responding through a number of new policies targeting the use of clean energy and renewable energy resources and improving energy efficiency which has already started to have positive results. Originality/value ? The paper provides a good practical guide to the current situation of energy consumption and policy implications for combating serious air quality issues in one of China's major urban centres. [ABSTRACT FROM AUTHOR]

Currently, air quality has become central to global environmental policymaking. As a typical mountain megacity in the Cheng-Yu region, the air pollution in Chongqing is unique and sensitive. This study aims to comprehensively investigate the long-term annual, seasonal, and monthly variation characteristics of six major pollutants and seven meteorological parameters. The emission distribution of major pollutants is also discussed. The relationship between pollutants and the multi-scale meteorological conditions was explored. The results indicate that particulate matter (PM), SO2 and NO2 showed a "U-shaped" variation, while O3 showed an "inverted U-shaped" seasonal variation. Industrial emissions accounted for 81.84%, 58% and 80.10% of the total SO2, NOx and dust pollution emissions, respectively. The correlation between PM2.5 and PM10 was strong (R = 0.98). In addition, PM only showed a significant negative correlation with O3. On the contrary, PM showed a significant positive correlation with other gaseous pollutants (SO2, NO2, CO). O3 is only negatively correlated with relative humidity and atmospheric pressure. These findings provide an accurate and effective countermeasure for the coordinated management of air pollution in Cheng-Yu region and the formulation of the regional carbon peaking roadmap. Furthermore, it can improve the prediction accuracy of air pollution under multi-scale meteorological factors, promote effective emission reduction paths and policies in the region, and provide references for related epidemiological research. [ABSTRACT FROM AUTHOR]

Accumulating evidence suggested that the risk of preterm births (PTBs) following prenatal exposure to air pollution was inconclusive. The aim of this study is to investigate the relationship between air pollution exposure in the days before delivery and PTB and assess the threshold effect of short-term prenatal exposure to air pollution on PTB. This study collected data including meteorological factors, air pollutants, and information in Birth Certificate System from 9 districts during 2015–2020 in Chongqing, China. Generalized additive models (GAMs) with the distributed lag non-linear models were conducted to assess the acute impact of air pollutants on the daily counts of PTB, after controlling for potential confounding factors. We observed that PM2.5 was related to increased occurrence of PTB on lag 0–3 and lag 10–21 days, with the strongest on the first day (RR = 1.017, 95%CI: 1.000–1.034) and then decreasing. The thresholds of PM2.5 for lag 1–7 and 1–30 days were 100 μg/m3 and 50 μg/m3, respectively. The lag effect of PM10 on PTB was very similar to that of PM2.5. In addition, the lagged and cumulative exposure of SO2 and NO2 was also associated with the increased risk of PTB. The lag relative risk and cumulative relative risk of CO exposure were the strongest, with a maximum RR at lag 0 (RR = 1.044, 95%CI: 1.018, 1.069). Importantly, the exposure–response curve of CO showed that RR increased rapidly when the concentration exceeded 1000 μg/m3. This study indicated significant associations between air pollution and PTB. The relative risk decreases with day lag, while the cumulative effect increases. Thus, pregnant women should understand the risk of air pollution and try to avoid high concentration exposure. [ABSTRACT FROM AUTHOR]

Studying the spatiotemporal characteristics of air pollutants in urban agglomerations and their response factors will help to improve the quality of urban living. In combining air quality monitoring data and wavelet analysis from the Chengdu-Chongqing urban agglomeration (CCUA), this study assessed the spatiotemporal distribution characteristics and influential factors of air pollutants on daily, monthly and annual scales. The results showed that the concentration of air pollutants in the CCUA has decreased year by year, and air quality has improved. Except for O 3 , pollutants in autumn and winter were higher than those in summer. The spatial distribution of air pollutants was obvious distributed in Chengdu, Chongqing, Zigong and Dazhou. Pollution incidents were mainly concentrated in winter. The 6 air pollutants and air quality index (AQI) have dominant periods on multiple time scales. AQI showed positive coherence with PM 2.5 and PM 10 on multiple time scales, and obvious positive coherence with SO 2 , CO, NO 2 and O 3 in the short term scale. AQI was not strongly correlated with the fire point, but exhibited obvious negative coherence in the long term scale. In addition, AQI showed an obvious positive correlation with temperature and sunshine hours in short term, and a clear negative correlation with humidity and rainfall. The research results of this paper will provide a reference for pollution prevention and control in the CCUA. • Wavelet and IDW used to analysis air pollutants spatiotemporal characteristics. • Air pollutants shows obvious periodicity and mutation. • There is a certain correlation between AQI and wild burning sites. • Rainfall and humidity have a scrubbing effect on air pollutants. • The research results can provide policy basis to improve air quality in region. [ABSTRACT FROM AUTHOR]

Background: Allergic rhinitis (AR) is a severe and the most common chronic allergic disease, affecting 10– 40% of the world population. The effect of air pollutants on AR has been confirmed in clinical experiments. Purpose: This study aimed to quantify the association between air pollutants and daily outpatient visits for AR in Chongqing, China. Methods: Based on the data of AR outpatients in the primary urban area of Chongqing from 2016 to 2017, along with the atmospheric pollutants and meteorological data in the same period, the distributed lag nonlinear model (DLNM) and generalized additive model (GAM) were used to analyze the time-series. We examined the effects of the single and double pollutant models with a maximum lag day of 30 days. Effect estimates were described as relative risk (RR) and 95% confidence intervals (CIs) in daily outpatient visits for AR per 10 μg/m3 increases in PM2.5, PM10, SO2, NO2, O3, and per 1 mg/m3 increase in CO. Results: A single pollutant's O3 level had an immediate positive effect on AR within two days, the relative risks (RR, 95% CI) were 1.066 (1.008– 1.127), 1.057 (1.005– 1.112) and 1.048 (1.002– 1.097). PM2.5 had a lag effect within 11– 18 days, the max relative risks (RR, 95% CI) were 1.083 (1.010– 1.160). Moreover, O3, PM2.5, PM10, SO2 and NO2 had significant effects on AR in the two-pollutant model. The RR cumulative effect of PM2.5 became more pronounced as the concentration increased. The cumulative effect of NO2 was lesser than PM2.5. Conclusion: Air pollutants were associated with the daily outpatient visits for AR, which may have considerable implications for developing tailored health policies and services to prevent AR in Chongqing and even all over the world. [ABSTRACT FROM AUTHOR]

The article discusses efforts to control air pollution in urban China. An increase in pollution from building sites and vehicles has created difficulties for local Chinese environmental protection bureaus (EPBs), as they do not have sole authority over such situations, but share oversight with other government agencies. Some of the challenges this poses for EPBs as they attempt to fulfill their missions are noted. An example from the city of Chongquing, where inter-agency coordination enabled the local EPB to implement Chongqing's Blue Sky Program is cited as an example of an effective means of handling such challenges.

This study provides insights into the spatial relationships among logistics agglomeration, technological progress, and air pollution in the sub-regions. From the perspective of new economic geography, the positive environmental externality of logistics agglomeration should outstrip its negative externality as the result of technological spillover. However, significant impacts of technological progress on the environment have not been identified in the logistics agglomeration sub-regions of many developing countries currently grappling with various environmental problems. This paper applies spatial econometrics and extended STIRPAT model to explore the roles the logistics agglomeration (LA) and technological progress (T) play in air pollution (I) using panel data from sub-regions of Chongqing in China between 2009 and 2019. The main conclusions are as follows. (1) In a global context, logistics agglomeration is a meaningful way to reduce air pollution under the interaction effect of technological progress. (2) In a sub-regional context: first, the suppressive effect of logistics agglomeration on air pollution gradually rebounds with the increase in agglomeration degree; secondly, the rebound effect of technological innovation is also evident in air pollution, and the rebound area gradually spreads from the metropolitan area to the peripheral sub-regions; finally, the interaction effect of logistics agglomeration and technological progress has a noteworthy suppression effect on air pollution, especially after the occurrence of the rebound effect of the logistics agglomeration and technological progress. In this regard, local governments should suppress the negative externalities of agglomeration with the interaction effects of technological progress while strengthening logistics agglomeration. [ABSTRACT FROM AUTHOR]

Chongqing City in China has suffered from serious air pollution and acid rain caused by low graded raw coal (sulfur=ca. 3≈5%, ash=ca. 30%) combustion. In this paper, the situation of atmospheric pollution and acid rain in Chongqing are discussed, the reduction efficiency for sulfur dioxide (SO2) with the bio-briquetting of the raw coal that is one of countermeasures for emission control of air pollutants due to domestic consumes was determined. The research indicated that the frequency of acid rain was high, more than 50% at urban area, and its pH was low, about 4.5. Under our experimental conditions, the reducing efficiency of sulfur SO2 emission from high sulfur coal-biomass briquette amounted to 87%. The field investigation indicated that SO2 indoor concentrations in case of using bio-briquette dropped to 1/2≈1/3 of the raw coal. [ABSTRACT FROM AUTHOR]

The United Kingdom Chemistry and Aerosols (UKCA) chemistry–climate model is used to quantify the differences in chemical environment for surface O3 for six major industrial regions across China in summer 2016. We first enhance the UKCA gas-phase chemistry scheme by incorporating reactive volatile organic compound (VOC) tracers that are necessary to represent urban and regional-scale O3 photochemistry. We demonstrate that the model with the improved chemistry scheme captures the observed magnitudes and diurnal patterns of surface O3 concentrations across these regions well. Simulated O3 concentrations are highest in Beijing and Shijiazhuang on the North China Plain and in Chongqing, lower in Shanghai and Nanjing in the Yangtze River Delta, and lowest in Guangzhou in the Pearl River Delta despite the highest daytime O3 production rates in Guangzhou. NOx / VOC and H2O2 / HNO3 ratios indicate that O3 production across all regions except Chongqing is VOC limited. We confirm this by constructing O3 response surfaces for each region changing NOx and VOC emissions and further contrast the effectiveness of measures to reduce surface O3 concentrations. In VOC-limited regions, reducing NOx emissions by 20 % leads to a substantial O3 increase (11 %) in Shanghai. We find that reductions in NOx emissions alone of more than 70 % are required to decrease O3 concentrations across all regions. Reductions in VOC emissions alone of 20 % produce the largest decrease (- 11 %) in O3 levels in Shanghai and Guangzhou and the smallest decrease (- 1 %) in Chongqing. These responses are substantially different from those currently found in highly populated regions in other parts of the world, likely due to higher NOx emission levels in these Chinese regions. Our work provides an assessment of the effectiveness of emission control strategies to mitigate surface O3 pollution in these major industrial regions and emphasises that combined NOx and VOC emission controls play a pivotal role in effectively offsetting high O3 levels. It also demonstrates new capabilities in capturing regional air pollution that will permit this model to be used for future studies of regional air-quality–climate interactions. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to study the relationship between air pollution and stroke (especially emergency stroke) in different regions and determine which air pollutant is the most significantly associated with stroke. Methods: The number of patients with emergency stroke, air pollutant data and related meteorological indicators were collected from December 2013 to May 2018 for large comprehensive hospitals in Chongqing. The generalized additive model was used to analyse the relationship between air pollution and emergency stroke. Results: After analysis and adjusting for meteorological indicators and day-of-the-week effects, in the one-pollutant model, every 10 μg/m3 increase in ozone(O3) was associated with a 2.482% (95% CI 1.044%, 3.919%) change in emergency strokes within lag0. For males, every 10 μg/m3 increase of O3 contributed to a 0.77% percent greater change compared with females. For the group younger than 60 years, we observed a 1.14% increase in risk with every 10 μg/m3 increase in O3. The group with pre-existing hypertension had a 0.26% higher risk than the group with no pre-existing hypertension with every 10 μg/m3 increase in O3. In two-pollutant model, when O3 was combined with a 10 μg/m3 increase of NO2, it increased the most significant risk of emergency stroke by 0.22%. Conclusion: These findings suggest that short-term exposure to O3 within 0 days is associated with emergency outpatient strokes, and younger people (age < 60 years) males and people with hypertension are more sensitive than older people, females and people without pre-existing hypertension. [ABSTRACT FROM AUTHOR]

Chemically speciated PM2.5 and particle-bound polycyclic aromatic hydrocarbon (PAH) measurements were made at three sites near urban Tong Liang, Chongqing, a Chinese inland city where coal combustion is used for electricity generation and residential purposes outside of the central city. Ambient sampling was based on 72-hr averages between 3/2/2002 and 2/26/2003. Elevated PM2.5 and PAR concentrations were observed at all three sites, with the highest concentrations found in winter and the lowest in summer. This reflects a coupling effect of source variability and meteorological conditions. The PM2.5 mass estimated from sulfate, nitrate, ammonium, organics, elemental carbon, crustal material, and salt corresponded with the annual average gravimetric mass within ± 10%. Carbonaceous aerosol was the dominant species, while positive correlations between organic carbon and trace elements (e.g., As, Se, Br, Pb, and Zn) were consistent with coal-burning and motor vehicle contributions. Ambient particle-bound PAHs of molecular weight 168-266 were enriched by 1.5 to 3.5 times during the coal-fired power plant operational period. However, further investigation is needed to determine the relative contribution from residential and utility coal combustion and vehicular activities. [ABSTRACT FROM AUTHOR]