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1.
Sci Total Environ ; 731: 139211, 2020 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-32402910

RESUMO

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

2.
Artigo em Inglês | MEDLINE | ID: mdl-32418095

RESUMO

Iron and steel industry emission is an important industrial source of air pollution. However, little is known about the relationship between volatile organic compounds (VOCs) emitted and regional air pollution. In this study, VOCs emissions from a typical iron and steel plant in Yangtze River Delta (YRD, China) were monitored from April 2018 to March 2019. The ozone formation potential (OFP) and secondary organic aerosol (SOA) formation of VOCs were calculated to reveal the influence of VOCs emissions on regional ozone and particulate pollution, and the sensitivity analysis approach was performed to explore the qualitative and quantitative relationships between VOCs and O3, as well as VOCs and PM2.5. The VOCs concentration was 93.76 ± 266.97 ppbv during the study. The OFP was 760.08 ± 2391.90 µg m-3, and aromatics were the predominant precursors, contributing 54.05% of the total OFP. Furthermore, the SOA estimated by fractional aerosol coefficient (FAC) and time-resolved (TR) methods were 6.032 ± 13.347 µg m-3 and 0.971 ± 4.650 µg m-3, accounting for 8.65-26.39% (13.78 ± 7.46%) and 1.55-4.20% (2.22 ± 1.23%) of the PM2.5 concentrations, respectively. The results indicated that VOCs were more sensitive to O3 pollution in high pollution domains, whereas VOCs were more sensitive to PM2.5 pollution in low pollution domains. We concluded that reducing VOCs emissions might be effective in alleviating photochemical pollution episodes in areas around iron and steel industry, and the haze pollution occurred in these regions may be caused by the primary emission of PM, and the contribution of SOA was relatively small.

3.
Chemosphere ; 252: 126600, 2020 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-32234631

RESUMO

Findings are inconsistent in studies for impacts of outdoor air pollutants on airway health in childhood. In this paper, we collected data regarding airway and allergic symptoms in the past year before a survey in 13,335 preschoolers from a cross-sectional study. Daily averaged concentrations of ambient sulphur dioxide (SO2), nitrogen dioxide (NO2), and particulate matter with an aerodynamic diameter ≤10 µm (PM10) in the past year before the survey were collected in the kindergarten-located district. We investigated associations of 12-month average concentrations of these pollutants with childhood airway and allergic symptoms. In the two-level (district-child) logistic regression analyses, exposure to higher level of NO2 and of PM10 increased odds of wheeze symptoms (adjusted OR, 95%CI: 1.03, 1.01-1.05 for per 3.0 µg/m3 increase in NO2; 1.22, 1.09-1.39 for per 7.6 µg/m3 increase in PM10), wheeze with a cold (1.03, 1.01-1.06; 1.22, 1.08-1.39), dry cough during night (1.05, 1.03-1.08; 1.23, 1.09-1.40), rhinitis symptoms (1.11, 1.08-1.13; 1.32, 1.07-1.63), rhinitis on pet (1.11, 1.05-1.18; 1.37, 0.95-1.98) and pollen (1.12, 1.03-1.21; 1.23, 0.84-1.82) exposure, eczema symptoms (1.09, 1.05-1.12; 1.22, 0.98-1.52), and lack of sleep due to eczema (1.12, 1.07-1.18; 1.58, 1.25-1.98). Exposures to NO2 and PM10 were also significantly and positively associated with the accumulative score of airway symptoms. Similar positive associations were found of NO2 and of PM10 with the individual symptoms and symptom scores among preschoolers from different kindergarten-located district. These results indicate that ambient NO2 and PM10 likely are risk factors for airway and allergic symptoms in childhood in Shanghai, China.

4.
Nature ; 2020 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-32340022

RESUMO

The ongoing COVID-19 outbreak has spread rapidly on a global scale. While the transmission of SARS-CoV-2 via human respiratory droplets and direct contact is clear, the potential for aerosol transmission is poorly understood1-3. This study investigated the aerodynamic nature of SARS-CoV-2 by measuring viral RNA in aerosols in different areas of two Wuhan hospitals during the COVID-19 outbreak in February and March 2020. The concentration of SARS-CoV-2 RNA in aerosols detected in isolation wards and ventilated patient rooms was very low, but it was elevated in the patients' toilet areas. Levels of airborne SARS-CoV-2 RNA in the majority of public areas was undetectable except in two areas prone to crowding, possibly due to infected carriers in the crowd. We found that some medical staff areas initially had high concentrations of viral RNA with aerosol size distributions showing peaks in submicrometre and/or supermicrometre regions, but these levels were reduced to undetectable levels after implementation of rigorous sanitization procedures. Although we have not established the infectivity of the virus detected in these hospital areas, we propose that SARS-CoV-2 may have the potential to be transmitted via aerosols. Our results indicate that room ventilation, open space, sanitization of protective apparel, and proper use and disinfection of toilet areas can effectively limit the concentration of SARS-CoV-2 RNA in aerosols. Future work should explore the infectivity of aerosolized virus.

5.
Sci Total Environ ; 720: 137431, 2020 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-32145615

RESUMO

Aircraft engine emissions during landing and take-off cycle are commonly estimated on the basis of the International Civil Aviation Organization (ICAO) promulgated calculation model and emission parameters; however, the ICAO certified parameters are generally not applicable for an individual airport. In this study, the operation times, fuel and emission parameters of 8 aircraft models during taxi phase at Shanghai Hongqiao International Airport (SHA) are analyzed with the Aircraft Communication Addressing and Reporting System (ACARS) data, and compared with corresponding values referenced by the ICAO. The results show perceptible discrepancies between the SHA-specific and ICAO certified values. The taxi-out times at SHA are considerably overestimated (up to 35.3%) by ICAO for all the analyzed aircraft models, whereas the taxi-in durations are highly close to the ICAO referenced value with a variation within -6.3% to 9.7%. In the majority of cases, the localized fuel flows and emission indices (EIs) are overvalued by ICAO, and the extent of overestimation can be as large as 21.6% and 28.3%, respectively. Variabilities in operation times, fuel and emission parameters are also characterized depending on aircraft types. Additionally, as a novel attempt, the effect of engine aging on EIs is explored and no significant correlation has been detected, indicating that other factors may affect the EIs dominantly over engine age. The resulting SHA-specific emission parameters are significant towards a precise emission quantification and modeling of impacts on air quality and health.

6.
Sci Total Environ ; 715: 136258, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32007868

RESUMO

Ground-based multi-axis differential optical absorption spectroscopy (MAX-DOAS) observations were performed from 27 December 2018 to 16 January 2019 in Changshou, one of subdistricts of Chongqing, China. Primary atmospheric pollutant in Changshou during wintertime was PM2.5, whose contribution averaged about 70.15% ± 9.5% of PM10. The ratio of PM2.5/PM10 decreased when PM2.5 pollution became worse, and it should attribute to biomass burning and the contribution of hygroscopic growth and enhanced heterogeneous chemistry under high relative humidity condition. Moreover, nitrogen dioxide (NO2), formaldehyde (HCHO) and glyoxal (CHOCHO) vertical profiles during the campaign period were retrieved separately. TROPOMI HCHO vertical column densities (VCDs) and MAX-DOAS HCHO VCDs were correlated well (R = 0.93). In order to identify the sources of volatile organic compound (VOC) in Changshou, the ratio of CHOCHO to HCHO (RGF) in five different layers were estimated. The estimated daily averaged RGF were 0.0205 ± 0.0077, 0.0727 ± 0.0286, 0.0864 ± 0.0296, 0.0770 ± 0.0275 and 0.0746 ± 0.0263 in 0-100 m, 100-200 m, 300-400 m, 500-600 m and 700-800 m layers, respectively. The estimated RGF will increase when biomass burnings were dominated. Using NO2 as a tracer of anthropogenic emissions, we found the RGF values gradually decrease with the increase of NO2 levels. RGF values in 0-100 m layer and all the other upper layers are 0.015-0.025 and 0.06-0.14, and that means the dominant sources of VOCs in 0-100 m layer and all the other upper layers are biogenic emission and anthropogenic emission (especially biomass burning), respectively. In addition, we found that RGF has site dependence which is in compliance with several previous studies.

7.
Environ Pollut ; 261: 114115, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32045794

RESUMO

The air traffic growth at Shanghai Pudong International Airport (PVG) has attracted much concern over the potential impacts on local air quality and human health; however, the emission contributions due to aircraft activities, impact on air quality and health effects remain unclear. In this study, the ground operational data derived from the Aircraft Communication Addressing and Reporting System (ACARS) dataset are newly utilized to obtain the PVG-specific emission parameters of 10 distinct aircraft-engine combinations during the taxi-in and taxi-out phases of the landing and take-off (LTO) cycle. The resulting emission parameters, together with PVG-specific operational conditions, are applied to quantify the annual emissions in 2017 for main engines and auxiliary power units (APUs) at PVG, emission variations caused by mixing layer height, sensitivity of black carbon (BC) emissions to the estimation method and sensitivity of PM2.5 emissions to the fuel sulfur content (FSC). The results show noticeable discrepancies between the corrected fuel flows and NOx emission indices (EIs) and those certified by the International Civil Aviation Organization (ICAO). The annual emissions of hydrocarbons (HC), CO, NOx, NO, NO2, HONO, HNO3, NOy, SO2, SO42-, BC, organic carbon (OC) and PM2.5 with corrected emission parameters are 3.82 × 105 kg, 4.35 × 106 kg, 5.36 × 106 kg, 4.40 × 106 kg, 9.58 × 105 kg, 1.03 × 105 kg, 3.83 × 103 kg, 5.47 × 106 kg, 3.56 × 105 kg, 1.31 × 104 kg, 5.43 × 104 kg, 4.73 × 103 kg and 7.22 × 104 kg, respectively, while the application of the maximum height of the mixing layer contributes to emission increases as high as 16.9% (NOx). An alternative estimation of BC emissions leads to an increase of 50% compared with first-order approximation 3 (FOA3), while a reduction in PM2.5 emissions can be expected by minimizing the FSC.

8.
Ecotoxicol Environ Saf ; 191: 110154, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31954217

RESUMO

Limited evidence is available for the associations between fine particulate matter (PM2.5) constituents and daily cardiovascular disease (CVD) mortality in China. In present study, a time-series analysis was conducted to evaluate the associations of PM2.5 constituents (two carbonaceous fractions, eight water-soluble inorganic ions and fifteen elements) with daily CVD mortality in Pudong New Area of Shanghai, China, from 2014 to 2016. Results showed that the effect estimates for the associations of PM2.5 and its constituents with CVD mortality were generally strongest when using the exposures of the previous two day concentrations. The associations of organic carbon, sulfate, ammonia, potassium, copper, arsenic, and lead with daily CVD mortality were robust to the adjustment of PM2.5 total mass, their collinearity with PM2.5 total mass, and criteria gaseous air pollutants. An interquartile range increase in the previous two day concentrations of PM2.5, organic carbon, sulfate, ammonia, potassium, copper, arsenic, and lead were associated with significant increments of 2.21% (95% confidence interval [95%CI]: 0.54%, 3.88%), 2.83% (95% CIs: 1.16%, 4.50%), 1.90% (95% CIs: 0.35%, 3.45%), 2.29% (95% CIs: 0.80%, 3.77%), 0.94% (95% CIs: 0.13%, 1.75%), 1.53% (95% CIs: 0.37%, 2.69%), 2.08% (95% CIs: 0.49%, 3.68%) and 1.98% (95% CIs: 0.49%, 3.47%) in daily CVD mortality, respectively, in single-pollutant models. In conclusion, this study suggested that organic carbon, sulfate, ammonia, potassium, copper, arsenic, and lead might be mainly responsible for the associations between short-term PM2.5 exposures and increased CVD mortality in Shanghai, China.


Assuntos
Poluentes Atmosféricos/toxicidade , Doenças Cardiovasculares/mortalidade , Material Particulado/toxicidade , Poluentes Atmosféricos/análise , China , Humanos , Material Particulado/análise
9.
Sci Total Environ ; 706: 135683, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31940722

RESUMO

Shanghai, a metropolitan city in China, has suffered from severe air pollution, especially PM2.5, in the last few years. Up to now the contribution of local emission and regional transport to the formation of haze in Shanghai remains unclear. With an aim to characterize the mechanism of haze formation in Shanghai, the present paper attempted to provide an overview of a tethered balloon-based field campaign. According to the backward trajectories, the air mass traveling slowly from Jiangsu province accounted for the highest PM2.5 concentration (66 ± 20 µg/m3). Seventy vertical profiles of PM2.5, NO, NO2, SO2 and O3 within 1000 m were obtained, through which a comparison study on the characteristics of the vertical distributions of air pollutants on clean days and haze days was conducted. When altitude increased, clearly decreasing pattern of PM2.5, NO, and NO2 was observed during the field campaign. Due to the low atmospheric boundary layer, the diffusion of air pollutants was suppressed, which favored the formation of haze. The results of the generalized additive model revealed NO2 could the most significant factor influencing the vertical distribution of PM2.5 in both clean and haze days. This study provides new insight into the sources and vertical distribution of PM2.5, which could offer references for air pollution modeling.

10.
Sci Total Environ ; 710: 135620, 2020 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-31785922

RESUMO

Since the concentrations of primary particles and secondary inorganic aerosol components have been reduced significantly due to stringent emission controls, quantifying the source contributions and regional transport of secondary organic aerosol (SOA) is critical to further improve air quality in eastern China. In this study, the Community Multiscale Air Quality (CMAQ) model coupled with the updated SAPRC-11 photochemical mechanism and a revised SOA module was applied to investigate the emission sector and regional contributions to SOA in winter 2015 (January 5-26, 2015) and 2016 (December 20, 2015-January 20, 2016) in the Yangtze River Delta (YRD). The model is generally capable of reproducing the observed SOA concentrations at the Qingpu Supersite in Shanghai. The observed and predicted SOA concentrations are 6.4 µg/m3 and 6.9 µg/m3 in winter 2015, and 5.7 µg/m3 and 9.6 µg/m3 in winter 2016. The mean fraction bias (MFB) of the hourly SOA predictions is 0.22 and 0.32, respectively. High SOA concentrations in the wintertime of YRD are mainly due to aromatic compounds and dicarbonyls (glyoxal and methylglyoxal), which, on average, account for 43% and 53% of total SOA, respectively. The average contributions of industrial, residential, and transportation sectors in the YRD region during the entire simulation periods are 61%, 22%, and 17%, respectively. At the Qingpu Supersite in Shanghai, the industrial sector contributes to as much as 65% of total SOA in the heavy pollution episode of 2016. The contributions from transportation and residential sectors are 16% and 17%, respectively, during the same episode. The industry emissions from the Jiangsu, Zhejiang, and Shanghai are major contributors to the SOA at the Qingpu supersite during the heavy-polluted episodes, accounting for 31%, 19%, and 14% of the total predicted SOA. This study represents the first detailed regional modeling study of source region contributions to SOA in the YRD region and the detailed analyses of SOA in two winters months complement the previous SOA source apportionment studies focusing on seasonal average contributions.

11.
Sci Total Environ ; 707: 135989, 2020 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-31874395

RESUMO

BACKGROUND: Systemic inflammation is considered one of the key mechanisms in the development of cardiovascular diseases induced by fine particulate matter (PM2.5) air pollution. However, evidence concerning the effects of various PM2.5 constituents on circulating inflammatory biomarkers were limited and inconsistent. OBJECTIVES: To evaluate the associations of short-term exposure to a variety of PM2.5 constituents with circulating inflammatory biomarkers. METHODS: We conducted a panel study from May to October 2016 among 40 healthy adults in Shanghai, China. We monitored the concentrations of 27 constituents of PM2.5. We applied linear mixed-effect models to analyze the associations of PM2.5 and its constituents with 7 inflammatory biomarkers, and further assessed the robustness of the associations by fitting models adjusting for PM2.5 mass and/or their collinearity. Benjamini-Hochberg false discovery rate was used to correct for multiple comparisons. RESULTS: The associations of PM2.5 were strongest at lag 0 d with tumor necrosis factor-α (TNF-α), at lag 1 d with interleukin-6, interleukin-8, and interleukin-17A, at lag 02 d with monocyte chemoattractant protein-1 (MCP-1) and intercellular adhesion molecule-1 (ICAM-1). After correcting for multiple comparisons in all models, Cl-, K+, Si, K, As, and Pb were significantly associated with interleukin-8; SO42- and Se were marginally significantly associated with interleukin-8; SO42-, As, and Se were marginally significantly associated with TNF-α; and Si, K, Zn, As, Se, and Pb were marginally significantly associated with MCP-1. CONCLUSIONS: Our results suggested that some constituents (SO42-, Cl-, K+, and some elements) might be mainly responsible for systemic inflammation triggered by short-term PM2.5 exposure.


Assuntos
Material Particulado/análise , Adulto , Poluentes Atmosféricos , Poluição do Ar , Biomarcadores , China , Exposição Ambiental , Humanos
12.
Chemosphere ; 238: 124634, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31473525

RESUMO

A cavity attenuated phase shift single scattering albedo monitor was set up on a tethered airship platform to study the vertical profiles of particle light extinction coefficient (bext) in the lower troposphere (<1000 m) in Shanghai during 12-29 December 2015. Clear transition heights (THs) for vertical profiles of bext during the polluted days (PM2.5 > 75 µg m-3) were observed below 1000 m. The vertical differences of bext were highly dynamic as the vertical variation in bext was significant by as much as 605 Mm-1. The TH was observed mostly at about 100-200 m, and 450-650 m during night and daytime, respectively, and was in a wide range of ∼50-900 m during 15:00-22:00 due to the low boundary layer and/or the transport of pollutants. In particular, the TH was consistently below 500 m throughout the day during highly polluted haze episodes, highlighting the important role of a stagnant atmosphere situation for high concentrations of PM2.5. The vertical distribution of bext did not have a constant rule with respect to relative humidity and wind. Sometimes, peak values of bext at ∼350 m and 500 m during daytime were caused by enhanced regional transport. During stagnant and highly polluted situations or well-mixed clean days, bext was usually uniformly distributed below and above the TH, respectively, although bext was much smaller above the TH. For other situations, local emissions, pollutant transport, and the physical and chemical characteristics of aerosols resulted in highly dynamic vertical profiles of bext.


Assuntos
Poluentes Atmosféricos/análise , Atmosfera/química , Monitoramento Ambiental/métodos , Material Particulado/análise , Aerossóis/análise , China , Estações do Ano , Vento
13.
Huan Jing Ke Xue ; 40(11): 4791-4800, 2019 Nov 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854544

RESUMO

In this study, long-term continuous monitoring of atmospheric new particle formation was conducted from 2015 to 2017 in the Shanghai suburbs using a scanning mobility particle sizer (SMPS). Combined with meteorological parameters, gaseous pollutants, and PM2.5 chemical composition data, the characterization of new particle formation was analyzed. The results of data analysis showed there were 172 new particle formation (NPF) days in the Shanghai suburbs, accounting for 18.3% of the total effective days (942 d). Typical new particle formation days (Event) and new particle growth-shrinkage (Shrinkage) days were 150 d and 32 d, respectively. The frequency of NPF occurrence was the highest in spring and summer, followed by autumn and winter. Compared with non-new particle formation (Non-NPF) days, Event and Shrinkage days had higher temperature and wind speed, lower humidity, less rainfall, and stronger solar radiation. The ratio of Event days was the highest when the prevailing wind was southerly, southwesterly, or westerly, and when the air masses were mainly from the vegetation cover and agricultural planting areas in the Taihu Lake Basin. The prevailing wind directions for Non-NPF and Shrinkage days were northeasterly and easterly to southeasterly. On the Event days, SO2 and O3 were higher than that on the Non-NPF days, indicating gaseous sulfuric acid and photochemical reactions were key contributors to new particle formation. Higher PM10 concentration was detected on the Event days than on the Non-NPF days, which may be attributed to the photocatalytic reaction. All the pollutant concentrations were the lowest on Shrinkage days, except that of O3. The average concentrations of inorganic components of PM2.5, such as NH4+, SO42-, and NO3- were higher on Event than on Non-NPF days in fall, whereas the opposite results were observed in other seasons. The average concentration of organic carbon on Event days was higher than that on Non-NPF days in each season. The concentrations of PM2.5 components on Shrinkage days were the lowest. However, the ratio of organic carbon on Shrinkage days was higher than that on Non-NPF days in spring, summer, and winter. The higher ratio of organic carbon on the NPF days than on the Non-NPF days suggested an important role of organic matter in the formation and growth of new particles in the suburbs of Shanghai.

14.
Proc Natl Acad Sci U S A ; 116(49): 24463-24469, 2019 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-31740599

RESUMO

From 2013 to 2017, with the implementation of the toughest-ever clean air policy in China, significant declines in fine particle (PM2.5) concentrations occurred nationwide. Here we estimate the drivers of the improved PM2.5 air quality and the associated health benefits in China from 2013 to 2017 based on a measure-specific integrated evaluation approach, which combines a bottom-up emission inventory, a chemical transport model, and epidemiological exposure-response functions. The estimated national population-weighted annual mean PM2.5 concentrations decreased from 61.8 (95%CI: 53.3-70.0) to 42.0 µg/m3 (95% CI: 35.7-48.6) in 5 y, with dominant contributions from anthropogenic emission abatements. Although interannual meteorological variations could significantly alter PM2.5 concentrations, the corresponding effects on the 5-y trends were relatively small. The measure-by-measure evaluation indicated that strengthening industrial emission standards (power plants and emission-intensive industrial sectors), upgrades on industrial boilers, phasing out outdated industrial capacities, and promoting clean fuels in the residential sector were major effective measures in reducing PM2.5 pollution and health burdens. These measures were estimated to contribute to 6.6- (95% CI: 5.9-7.1), 4.4- (95% CI: 3.8-4.9), 2.8- (95% CI: 2.5-3.0), and 2.2- (95% CI: 2.0-2.5) µg/m3 declines in the national PM2.5 concentration in 2017, respectively, and further reduced PM2.5-attributable excess deaths by 0.37 million (95% CI: 0.35-0.39), or 92% of the total avoided deaths. Our study confirms the effectiveness of China's recent clean air actions, and the measure-by-measure evaluation provides insights into future clean air policy making in China and in other developing and polluting countries.

15.
Environ Pollut ; 255(Pt 1): 113157, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31541838

RESUMO

As one of the highest energy consuming and polluting industries, the power generation industry is an important source of particulate matter emissions. Recently, implementation of ultra-low emission technology has changed the emission characteristic of fine particulate matter (PM2.5). In this study, PM2.5 emitted from four typical power plants in China was sampled using a dilution channel sampling system, and analyzed for elements, water-soluble ions and carbonaceous fractions. The results showed that PM2.5 concentrations emitted from the four power plants were 0.78 ±â€¯0.16, 0.63 ±â€¯0.09, 0.29 ±â€¯0.07 and 0.28 ±â€¯0.01 mg m-3, respectively. Emission factors were 0.004-0.005 g/kg coal, nearly 1-2 orders of magnitude lower than those reported in previous studies. The highest proportions of PM2.5 consisted of organic carbon (OC), SO42-, elemental carbon (EC), NH4+, Al and Cl-. Coefficients of divergence (CDs) were in the ranges 0.22-0.41 (for an individual plant), 0.43-0.69 (among different plants), and 0.60-0.99 (in previous studies). The results indicated that the source profiles of each tested power plant were relatively similar, but differed from those in previous studies. Enrichment factors showed elevated Se and Hg, in accordance with the source markers Se and As. Comparing source profiles with previous studies, the proportion of OC, EC and NH4+ were higher, while the proportion of Al in PM2.5 were relatively lower. The OC/EC ratio became concentrated at ∼5. Results from this study can be used for source apportionment and emission inventory calculations after implementation of ultra-low emission technologies.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Material Particulado/análise , Centrais Elétricas , Alumínio/análise , Arsênico/análise , Carbono/análise , China , Carvão Mineral/análise , Mercúrio/análise , Selênio/análise , Água/química
16.
Sci Total Environ ; 695: 133780, 2019 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-31416039

RESUMO

BACKGROUND: The identification of constituents of fine particulate matter (PM2.5) air pollution that had key impacts of ischemic stroke (the predominant subtype of stroke) is important to understand the underlying biological mechanisms and develop air pollution control policies. OBJECTIVES: To explore the associations between PM2.5 constituents and hospitalization for ischemic stroke in Shanghai, China. METHODS: We conducted a time-series study to explore the associations between 27 constituents of PM2.5 and hospitalization for ischemic stroke in Shanghai, China from 2014 to 2016. The over-dispersed generalized additive models with adjustment for time, day of week, holidays, and weather conditions were used to estimate the associations. We also evaluated the robustness of the effect estimates for each constituent after adjusting for the confounding effects of PM2.5 total mass and gaseous pollutants and the collinearity (the residual) between this constituent and PM2.5 total mass. We also compared the associations between seasons. RESULTS: In total, we identified 4186 ischemic stroke hospitalizations during the study period. The associations of ischemic stroke were consistently significant with elemental carbon and several elemental constituents (Chromium, Iron, Copper, Zinc, Arsenic, Selenium, and Lead) at lag 1 day in single-constituent models, models adjusting for PM2.5 total mass or gaseous pollutants and models adjusting for collinearity. The associations were much stronger in cool season than in warm season. CONCLUSIONS: The current study provides suggestive evidence that elemental carbon and some metallic elements may be mainly responsible for the risks of ischemic stroke hospitalization induced by short-term PM2.5 exposure.


Assuntos
Poluição do Ar/estatística & dados numéricos , Exposição Ambiental/estatística & dados numéricos , Material Particulado/análise , Acidente Vascular Cerebral/epidemiologia , Poluentes Atmosféricos , China/epidemiologia , Hospitalização/estatística & dados numéricos
17.
Environ Pollut ; 254(Pt A): 112864, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31369912

RESUMO

To better understand the mechanism of PM2.5 explosive growth (EG), we conducted concurrent measurements of gaseous pollutants, PM2.5 and its chemical composition (inorganic ions, organic carbon, and element carbon) with a time resolution of 1 h in Shanghai in late autumn and winter from 2014 to 2017. In this study, the EG events, which are defined as the net increase in the mass concentration of PM2.5 by more than 100 µg m-3 within hours, are separately discussed for 3, 6, or 9 h. The number of EG events decreased from 19 cases in 2014 to 6 cases in 2017 and the corresponding PM2.5 concentration on average decreased from 183.6 µg m-3 to 128.8 µg m-3. Both regional transport and stagnant weather (windspeed < 2.0 m s-1) could lead to EG events. The potential source contribution function (PSCF) shows that the major high-pollution region is in East China (including Zhejiang, Jiangsu, Shandong, and Anhui Province) and the North China Plain. The contribution of stagnant conditions to EG episode hours of 55% (198 h, 156.9 µg m-3) is higher than that of regional transport (45%, 230 h, 163.0 µg m-3). To study the impact of local emission, chemical characteristics and driving factors of EG were discussed under stagnant conditions. The major components contributing to PM2.5 are NO3- (17.9%), organics (14.1%), SO42- (13.1%), and NH4+ (13.1%). The driving factors of EG events are the secondary aerosol formation of sulfate and nitrate and primary emissions (vehicle emissions, fireworks, and biomass burning), but the secondary transformation contributes more to EG events. The formation of sulfate and nitrate is dominated by gas-phase oxidation and heterogeneous reactions, which are enhanced by a high relative humidity. The current study helps to understand the chemical mechanism of haze and provides a scientific basis for air pollution control in Shanghai.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental , Material Particulado/análise , Aerossóis/análise , Carbono/análise , China , Poluentes Ambientais , Poluição Ambiental , Gases , Nitratos/análise , Óxidos de Nitrogênio , Estações do Ano , Sulfatos/análise , Emissões de Veículos/análise , Tempo (Meteorologia)
18.
Environ Sci Technol ; 53(19): 11580-11587, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31456399

RESUMO

This study aims to understand the effect of the Domestic Emission Control Area (DECA) policy on ambient SO2 and particle components in Shanghai. Online single particle analysis and SO2 measurements from 2015 to 2017 were compared to analyze the long-term variations before and after the DECA policy. Our study showed that there was a significant decrease in SO2 by 27-55% after the implementation of the DECA policy. The number fraction of ship-emitted particles increased along with the increase in ship traffic activity, but the particles tended to contain lower-vanadium content. The elemental carbon component decreased, while the organic carbon components increased after switching oil. One thousand and ninety four ship fuel oil samples were collected. The oil sample analysis confirmed the ambient particle results; sulfur content decreased in domestic ship heavy fuel oils from 2013 to 2018; in the low sulfur fuel oils used after the DECA policy, vanadium was still highly correlated with sulfur as it was in high-sulfur fuels. Our results suggested that heavy fuel oil is still a major part of the low-sulfur ship oils in use. The multiple-component control including organic pollutants regarding low sulfur fuel oils may be necessary for preventing air pollution from ship emissions.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , China , Material Particulado , Navios , Emissões de Veículos
19.
Environ Int ; 131: 105019, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31330363

RESUMO

BACKGROUND: Fine particulate matter (PM2.5) has been widely associated with airway inflammation represented by increased fractional concentration of exhaled nitric oxide (FeNO). However, it remains unclear whether various PM2.5 constituents have different impacts on FeNO and its production process from the arginase (ARG)-nitric oxide synthase (NOS) pathway. OBJECTIVES: To investigate the acute effects of PM2.5 constituents on FeNO and DNA methylation of genes involved. METHODS: We conducted a longitudinal panel study among 43 young adults in Shanghai, China from May to October in 2016. We monitored the concentrations of 25 constituents of PM2.5. We applied the linear mixed-effect model to evaluate the associations of PM2.5 constituents with FeNO and DNA methylation of the ARG2 and NOS2A genes. RESULTS: Following PM2.5 exposure, NOS2A methylation decreased and ARG2 methylation increased only on the concurrent day, whereas FeNO increased most prominently on the second day. Nine constituents (OC, EC, K, Fe, Zn, Ba, Cr, Se, and Pb) showed consistent associations with elevated FeNO and decreased NOS2A methylation or increased ARG2 methylation in single-constituent models and models adjusting for PM2.5 total mass and collinearity. An interquartile range increase of these constituents was associated with respective decrements of 0.27-1.20 in NOS2A methylation (%5mC); increments of 0.48-1.56 in ARG2 methylation (%5mC); and increments of 7.12%-17.54% in FeNO. CONCLUSIONS: Our results suggested that OC, EC, and some metallic elements may be mainly responsible for the development and epigenetic regulation of airway inflammatory response induced by short-term PM2.5 exposure.


Assuntos
Arginase/metabolismo , Metilação de DNA/efeitos dos fármacos , Óxido Nítrico Sintase Tipo II/metabolismo , Óxido Nítrico/metabolismo , Material Particulado/farmacologia , Adulto , China , Expiração , Feminino , Humanos , Estudos Longitudinais , Masculino , Material Particulado/análise , Adulto Jovem
20.
Environ Sci Pollut Res Int ; 26(23): 24305-24312, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31256395

RESUMO

Identifying the sources of volatile organic compounds (VOCs) is key to air quality control and pollution prevention. Though receptor models have been widely used in source apportionment of VOCs, they are not applicable to identify the potential source of labile species. In this study, the potential source of methyl mercaptan (MeSH) near a large refining and petrochemical plant was identified using an indirect method. When wind directions were controlled, the study period was separated into two subperiods depending on the detection of MeSH. Relative contributions from potential sources were predicted by chemical mass balance model and positive matrix factorization model based on ambient concentrations of sulfur-free compounds. Both models predicted that petroleum refinery and petrochemical production were the dominant sources of VOCs in the study area. When MeSH was detected, the relative contribution from gasoline, liquefied petroleum gas, or crude oil increased by 7.4 to 26.8% point, depending on wind direction and the predictive model used, suggesting a close relationship between MeSH and the emission from petroleum refinery. Consistent with the indirect source apportionment, among the coexisting VOCs, MeSH was most highly correlated or associated with ethane, propane, isobutane, cis-2-pentente, and isoprene, which are major components of the products or by-products of petrochemical refining processes.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Modelos Químicos , Compostos de Sulfidrila/análise , Poluição do Ar , Gasolina , Petróleo , Compostos Orgânicos Voláteis/análise , Vento
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