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1.
Philos Trans A Math Phys Eng Sci ; 378(2183): 20200188, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-32981442

RESUMO

We suggest that the unprecedented and unintended decrease of emissions of air pollutants during the COVID-19 lock-down in 2020 could lead to declining seasonal ozone concentrations and positive impacts on crop yields. An initial assessment of the potential effects of COVID-19 emission reductions was made using a set of six scenarios that variously assumed annual European and global emission reductions of 30% and 50% for the energy, industry, road transport and international shipping sectors, and 80% for the aviation sector. The greatest ozone reductions during the growing season reached up to 12 ppb over crop growing regions in Asia and up to 6 ppb in North America and Europe for the 50% global reduction scenario. In Europe, ozone responses are more sensitive to emission declines in other continents, international shipping and aviation than to emissions changes within Europe. We demonstrate that for wheat the overall magnitude of ozone precursor emission changes could lead to yield improvements between 2% and 8%. The expected magnitude of ozone precursor emission reductions during the Northern Hemisphere growing season in 2020 presents an opportunity to test and improve crop models and experimentally based exposure response relationships of ozone impacts on crops, under real-world conditions. This article is part of a discussion meeting issue 'Air quality, past present and future'.


Assuntos
Poluição do Ar/análise , Betacoronavirus , Infecções por Coronavirus/epidemiologia , Produtos Agrícolas/efeitos dos fármacos , Produtos Agrícolas/crescimento & desenvolvimento , Ozônio/análise , Pandemias , Pneumonia Viral/epidemiologia , Poluentes Atmosféricos/análise , Poluentes Atmosféricos/toxicidade , Poluição do Ar/prevenção & controle , Poluição do Ar/estatística & dados numéricos , Monitoramento Ambiental , Europa (Continente) , Humanos , Modelos Biológicos , Dióxido de Nitrogênio/análise , Dióxido de Nitrogênio/toxicidade , Ozônio/toxicidade , Medição de Risco , Estações do Ano
2.
Ecotoxicol Environ Saf ; 202: 110923, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32800210

RESUMO

Many studies have reported that exposure to ambient air pollution has adverse effects on health. However, there are little researches to explore the relationship between ambient air pollution and chronic sinusitis (CS). From January 1 2015 to December 31 2018, a time-series study were carried out to investigate the acute adverse roles of six criteria ambient air pollutants (fine particulate matter [PM2.5], inhalable particulate matter [PM10], nitrogen dioxide [NO2], sulfur dioxide [SO2], ozone [O3], and carbon monoxide [CO]) in hospital outpatients with CS in Xinxiang, China. Then, an over-dispersed Poisson generalized additive model was utilized to analyzed the relationships. In total, 183,943 hospital outpatient cases of CS were identified during the study period. We found that a 10 µg/m3 increase in PM2.5, PM10, SO2, NO2, and CO corresponded to 0.48% (95% confidence interval: 0.22-0.74%), 0.33% (0.16-0.50%), 0.88% (0.13-1.62%), 1.98% (1.31-2.64%), and 0.05% (0.03-0.07%) increments, respectively, in CS outpatients on the current day. The young group (<15 years of age) was more susceptible than the adult or elderly groups. These results suggested that outdoor air pollutants might increase CS outpatient, especially among youth in Xinxiang. Precautions and protective measures should be strengthened to reduce the air pollution level in the future.


Assuntos
Poluentes Atmosféricos/toxicidade , Poluição do Ar/estatística & dados numéricos , Exposição por Inalação/estatística & dados numéricos , Sinusite/epidemiologia , Adolescente , Adulto , Idoso , Poluentes Atmosféricos/análise , Poluição do Ar/efeitos adversos , Monóxido de Carbono/análise , China/epidemiologia , Doença Crônica , Feminino , Humanos , Masculino , Dióxido de Nitrogênio/análise , Pacientes Ambulatoriais , Ozônio/análise , Material Particulado/análise , Sinusite/induzido quimicamente , Dióxido de Enxofre/análise , Adulto Jovem
3.
J Environ Sci (China) ; 96: 138-150, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32819688

RESUMO

Speciated characterization of Volatile Organic Compounds (VOCs), including oxygenated VOCs (OVOCs), from construction machinery and river ships in China is currently lacking. In this regard, we conducted field measurement on speciated VOC (including OVOC) emissions from six construction machinery and five river ships in the Pearl River Delta (PRD) region to identify VOC emission characteristics. We noticed that OVOC emissions from construction machinery and ships accounted for more than 50% of the total VOC emissions, followed by alkenes, aromatics and alkanes. Formaldehyde and acetaldehyde were the most emission species, accounting for 61.8%-83.2% of OVOCs. For construction machinery, the fuel-based emission factors of roller, grader and pile driver were 3.12, 3.12 and 7.36 g/kg, respectively. With the rigorous restraint by the national emission standards, VOC emissions of construction machinery had decreased considerably, especially during stage Ⅲ. Ozone formation potential was also significantly reduced due to the significant decrease in emissions of OVOCs and alkenes with higher reactivity. For river ships, the fuel-based emission factors of cargo ships and speedboat were 1.46 and 0.44 g/kg, respectively. VOC emissions from construction machinery and river ships in Guangdong Province in 2017 were 8851.0 and 4361.0 ton, respectively. This study filled the knowledge gaps of reactive gas emissions from different kinds of non-road mobile sources over the PRD, and more importantly, highlighted the necessity in adding OVOC measurement to give a complete and accurate depiction of reactive gas emissions from non-road mobile sources.


Assuntos
Poluentes Atmosféricos/análise , Ozônio/análise , Compostos Orgânicos Voláteis/análise , China , Monitoramento Ambiental , Rios , Navios , Emissões de Veículos/análise
4.
Environ Monit Assess ; 192(9): 591, 2020 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-32820457

RESUMO

Identifying an ozone pollution zone during the pollution processes is significant for ozone pollution management and environmental health risk assessment. However, few studies have focused on ozone pollution zone identification during pollution processes. A spatial-temporal clustering framework for identifying pollution zones during ozone pollution processes was initially proposed in this study, and an ozone pollution process in China in May 2017 was selected as a case. The results showed that the framework can help selecting one more accurate method to identify the pollution zone according to the pollution characteristics of air pollution process. In addition, different ozone pollution zone identification methods work well in different scenarios: The self-organizing map (SOM) method was suitable for identifying the zone with the duration of pollution between 24 and 48 h, the image fusion based on wavelet transform (IFbWT) method for the zone with the duration of pollution over 48 h and the Apriori method for the zone with obvious boundaries between high-value and low-value ozone concentrations. The proposed procedure can also be applied to identify the pollution zone of the pollution process of other pollutants.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/análise , Ozônio/análise , China , Monitoramento Ambiental
5.
J Environ Manage ; 272: 111024, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32854874

RESUMO

Home to one-fourth of the world's population and ranked amongst the fastest growing economies, the South Asian countries are marred with the predicament of inexorable pollution. Amidst the growing pollutants, ground-level ozone has become an important component in understanding health, and productivity of agricultural crops. In this regard spatio-temporal analysis of tropospheric ozone for wheat, rice and cotton crops was carried out. Followed-up with a multivariate regression model; establishing a statistical relationship between tropospheric ozone (TO) and crop productivity. The results indicate that predominantly ozone is increasing, with a significant trend visible in all crop growing seasons. Observations indicate higher concentrations of TO in the rice & cotton growing seasons, with a seasonal average of 68 ppb, compared to wheat growing season (55 ppb). Regression results specify that with an increase of 1% in tropospheric ozone concentration within the study area; crop productivity decreases for cotton (-4.0%), rice (-2.3%), and wheat (-0.7%). Furthermore, with the presence of the dominant tropospheric ozone in the regression model, the temperature's impact on productivity becomes statistically inconsequential.


Assuntos
Poluentes Atmosféricos/análise , Ozônio/análise , Mudança Climática , Produtos Agrícolas , Índia , Estações do Ano
6.
Sci Rep ; 10(1): 13442, 2020 08 10.
Artigo em Inglês | MEDLINE | ID: mdl-32778673

RESUMO

Delhi, a tropical Indian megacity, experiences one of the most severe air pollution in the world, linked with diverse anthropogenic and biomass burning emissions. First phase of COVID-19 lockdown in India, implemented during 25 March to 14 April 2020 resulted in a dramatic near-zeroing of various activities (e.g. traffic, industries, constructions), except the "essential services". Here, we analysed variations in the fine particulate matter (PM2.5) over the Delhi-National Capital Region. Measurements revealed large reductions (by 40-70%) in PM2.5 during the first week of lockdown (25-31 March 2020) as compared to the pre-lockdown conditions. However, O3 pollution remained high during the lockdown due to non-linear chemistry and dynamics under low aerosol loading. Notably, events of enhanced PM2.5 levels (300-400 µg m-3) were observed during night and early morning hours in the first week of April after air temperatures fell close to the dew-point (~ 15-17 °C). A haze formation mechanism is suggested through uplifting of fine particles, which is reinforced by condensation of moisture following the sunrise. The study highlights a highly complex interplay between the baseline pollution and meteorology leading to counter intuitive enhancements in pollution, besides an overall improvement in air quality during the COVID-19 lockdown in this part of the world.


Assuntos
Poluentes Atmosféricos/análise , Betacoronavirus , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/prevenção & controle , Pandemias/prevenção & controle , Material Particulado/análise , Pneumonia Viral/epidemiologia , Pneumonia Viral/prevenção & controle , Quarentena/métodos , Tempo (Meteorologia) , Aerossóis/análise , Poluição do Ar/análise , Cidades/epidemiologia , Infecções por Coronavirus/virologia , Monitoramento Ambiental/métodos , Humanos , Índia/epidemiologia , Ozônio/análise , Pneumonia Viral/virologia , Temperatura
7.
Nat Commun ; 11(1): 4229, 2020 08 25.
Artigo em Inglês | MEDLINE | ID: mdl-32843631

RESUMO

Scarlet fever has resurged in China starting in 2011, and the environment is one of the potential reasons. Nationwide data on 655,039 scarlet fever cases and six air pollutants were retrieved. Exposure risks were evaluated by multivariate distributed lag nonlinear models and a meta-regression model. We show that the average incidence in 2011-2018 was twice that in 2004-2010 [RR = 2.30 (4.40 vs. 1.91), 95% CI: 2.29-2.31; p < 0.001] and generally lower in the summer and winter holiday (p = 0.005). A low to moderate correlation was seen between scarlet fever and monthly NO2 (r = 0.21) and O3 (r = 0.11). A 10 µg/m3 increase of NO2 and O3 was significantly associated with scarlet fever, with a cumulative RR of 1.06 (95% CI: 1.02-1.10) and 1.04 (95% CI: 1.01-1.07), respectively, at a lag of 0 to 15 months. In conclusion, long-term exposure to ambient NO2 and O3 may be associated with an increased risk of scarlet fever incidence, but direct causality is not established.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/análise , Exposição Ambiental/análise , Escarlatina/diagnóstico , Poluição do Ar/efeitos adversos , China/epidemiologia , Exposição Ambiental/efeitos adversos , Geografia , Humanos , Incidência , Dióxido de Nitrogênio/análise , Dinâmica não Linear , Ozônio/análise , Material Particulado/análise , Fatores de Risco , Escarlatina/epidemiologia , Escarlatina/etiologia , Estações do Ano , Análise Espaço-Temporal
8.
Zhonghua Yu Fang Yi Xue Za Zhi ; 54(7): 774-778, 2020 Jul 06.
Artigo em Chinês | MEDLINE | ID: mdl-32842301

RESUMO

Objective: To evaluate the effects of exposure of fine particle matter (PM2.5) and ozone (O3) in Beijing as the main pollutants on olfaction of SD rats. Methods: In October 16, 2018, twenty 8-week-old SD rats were randomly divided into two groups, 10 rats in the exposure group and 10 rats in the control group. They were fed in air pollutant exposure system and clean experimental environment respectively, and the concentrations of PM2.5 and O3 in each system were measured. The degree of olfaction damage of SD rats at different feeding time was assessed by using the buried food test (BFT). The difference of BFT time between the two groups was analyzed by performing the repeated measures analysis of variance. Results: The results showed that the concentrations of PM2.5 and O3 in the exposure group were (22.65±11.47) µg/m3 and (12.36±5.87) µg/m3, respectively, while those in the control group were both 0 µg/m3. The repeated measures analysis of variance showed that the time of BFT in the exposure group was longer than that in the control group (F=6.49, P=0.031). With the increase of feeding time, the time of BFT was prolonged (F=61.69, P<0.001). Conclusion: Exposure to PM2.5 and O3 in the atmosphere might lead to olfaction damage in rats.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/efeitos adversos , Ozônio/análise , Animais , Pequim , Material Particulado/análise , Ratos , Ratos Sprague-Dawley , Olfato
9.
Sci Total Environ ; 745: 141023, 2020 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-32738690

RESUMO

We study the variation of tropospheric NO2 vertical column densities (TropNO2VCDs) over East China during the 2005-2020 lunar new year (LNY) holiday seasons to understand factors on the reduction of tropospheric NO2 during the outbreak of COVID-19 in East China using Ozone Monitoring Instrument (OMI) and TROPOspheric Monitoring Instrument (TROPOMI) observations. TropNO2VCDs from OMI and TROPOMI reveal sharp reductions of 33%-72% during 2020 LNY holiday season and the co-occurring outbreak of COVID-19 relative to the climatological mean of 2005-2019 LNY holiday seasons, and 22%-67% reduction relative to the 2019 LNY holiday season. These reductions of TropNO2VCD occur majorly over highly polluted metropolitan areas with condensed industrial and transportation emission sources. COVID-19 control measures including lockdowns and shelter-in-place regulations are the primary reason for these tropospheric NO2 reductions over most areas of East China in 2020 LNY holiday season relative to the 2019 LNY holiday season, as COVID-19 control measures may explain ~87%-90% of tropospheric NO2 reduction in Wuhan as well as ~62%-89% in Beijing, Yangtze River Delta (YRD) and Sichuan Basin areas. The clean air regulation of China also contributes significantly to reductions of tropospheric NO2 simultaneously and is the primary factor in the Pearl River Delta (PRD) area, by explaining ~56%-63% of the tropospheric NO2 reduction there.


Assuntos
Poluentes Atmosféricos/análise , Infecções por Coronavirus , Ozônio/análise , Pandemias , Pneumonia Viral , Pequim , Betacoronavirus , China/epidemiologia , Monitoramento Ambiental , Humanos , Dióxido de Nitrogênio/análise , Estações do Ano
11.
Artigo em Inglês | MEDLINE | ID: mdl-32679925

RESUMO

Statistical methods such as multiple linear regression (MLR) and classification and regression tree (CART) analysis were used to build prediction models for the levels of pollutant concentrations in Macao using meteorological and air quality historical data to three periods: (i) from 2013 to 2016, (ii) from 2015 to 2018, and (iii) from 2013 to 2018. The variables retained by the models were identical for nitrogen dioxide (NO2), particulate matter (PM10), PM2.5, but not for ozone (O3) Air pollution data from 2019 was used for validation purposes. The model for the 2013 to 2018 period was the one that performed best in prediction of the next-day concentrations levels in 2019, with high coefficient of determination (R2), between predicted and observed daily average concentrations (between 0.78 and 0.89 for all pollutants), and low root mean square error (RMSE), mean absolute error (MAE), and biases (BIAS). To understand if the prediction model was robust to extreme variations in pollutants concentration, a test was performed under the circumstances of a high pollution episode for PM2.5 and O3 during 2019, and the low pollution episode during the period of implementation of the preventive measures for COVID-19 pandemic. Regarding the high pollution episode, the period of the Chinese National Holiday of 2019 was selected, in which high concentration levels were identified for PM2.5 and O3, with peaks of daily concentration exceeding 55 µg/m3 and 400 µg/m3, respectively. The 2013 to 2018 model successfully predicted this high pollution episode with high coefficients of determination (of 0.92 for PM2.5 and 0.82 for O3). The low pollution episode for PM2.5 and O3 was identified during the 2020 COVID-19 pandemic period, with a low record of daily concentration for PM2.5 levels at 2 µg/m3 and O3 levels at 50 µg/m3, respectively. The 2013 to 2018 model successfully predicted the low pollution episode for PM2.5 and O3 with a high coefficient of determination (0.86 and 0.84, respectively). Overall, the results demonstrate that the statistical forecast model is robust and able to correctly reproduce extreme air pollution events of both high and low concentration levels.


Assuntos
Betacoronavirus/isolamento & purificação , Infecções por Coronavirus/epidemiologia , Férias e Feriados , Material Particulado/análise , Pneumonia Viral/epidemiologia , Infecções por Coronavirus/virologia , Previsões , Humanos , Macau , Modelos Estatísticos , Dióxido de Nitrogênio/análise , Ozônio/análise , Pandemias , Pneumonia Viral/virologia , Análise de Regressão
12.
J Environ Sci (China) ; 95: 121-129, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32653171

RESUMO

Volatile organic compounds (VOCs) as precursors of ozone and secondary organic aerosols can cause adverse effects on the environment and human health. However, knowledge of the VOC vertical profile in the lower troposphere of major Chinese cities is poorly understood. In this study, tethered balloon flights were conducted over the juncture of Beijing-Tianjin-Hebei in China during the winter of 2016. Thirty-six vertical air samples were collected on selected heavy and light pollution days at altitudes of 50-1000 meters above ground level. On average, the concentration of total VOCs (TVOCs) at 50-100 m was 4.9 times higher than at 900-1000 m (46.9 ppbV vs. 8.0 ppbV). TVOC concentrations changed rapidly from altitudes of 50-100 to 401-500 m, with an average decrease of 72%. With further altitude increase, the TVOC concentration gradually decreased. The xylene/benzene ratios of 34/36 air samples were lower than 1.1, and the benzene/toluene ratios of 34/36 samples were higher than 0.4, indicating the occurrence of aged air mass during the sampling period. Alkenes contributed most in terms of both OH loss rate (39%-71%) and ozone formation potential (40%-72%), followed by aromatics (6%-38%). Finally, the main factors affecting the vertical distributions of VOCs were local source emission and negative dispersion conditions on polluted days. These data could advance our scientific understanding of VOC vertical distribution.


Assuntos
Poluentes Atmosféricos/análise , Ozônio/análise , Compostos Orgânicos Voláteis/análise , Pequim , China , Cidades , Monitoramento Ambiental , Humanos
13.
J Environ Sci (China) ; 95: 14-22, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32653173

RESUMO

A new state-of-the-art indoor smog chamber facility (CAPS-ZJU) has been constructed and characterized at Zhejiang University, which is designed for chemical mechanism evaluation under well-controlled conditions. A series of characterization experiments were performed to validate the well-established experimental protocols, including temperature variation pattern, light spectrum and equivalent intensity (JNO2), injection and mixing performance, as well as gases and particle wall loss. In addition, based on some characterization experiments, the auxiliary wall mechanism has been setup and examined. Fifty chamber experiments were performed across a broad range of experimental scenarios, and we demonstrated the ability to utilize these chamber data for evaluating SAPRC chemical mechanism. It was found that the SAPRC-11 can well predict the O3 formation and NO oxidation for almost all propene runs, with 6 hr Δ(O3 - NO) model error of -3% ± 7%, while the final O3 was underestimated by ~20% for isoprene experiments. As for toluene and p-xylene experiments, it was confirmed that SAPRC-11 has significant improvement on aromatic chemistry than earlier version of SAPRC-07, although the aromatic decay rate was still underestimated to some extent. The model sensitivity test has been carried out, and the most sensitive parameters identified are the initial concentrations of reactants and the light intensity as well as HONO offgasing rate and O3 wall loss rate. All of which demonstrated that CAPS-ZJU smog chamber could derive high quality experimental data, and could provide insights on chamber studies and chemical mechanism development.


Assuntos
Poluentes Atmosféricos/análise , Ozônio/análise , Oxirredução , Smog/análise , Tolueno
14.
J Environ Sci (China) ; 95: 183-189, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32653178

RESUMO

Coking industry is an important volatile organic compounds (VOCs) emission source in China, however, detailed information on VOCs emissions is lacking. Therefore, we selected a typical mechanized coking plant and collected air samples according to the Emission Standard of Pollutants for Coking Chemical Industry (GB16171-2012). Using gas chromatography-mass spectrometry method, we analyzed the VOCs in the air samples, and applied maximum increment reactivity (MIR) rule to estimate ozone formation potential (OFP) of the VOCs emitted from the coke production. More than 90 VOCs species were detected from the coking plant, including alkanes, alkenes, alkynes, aromatic hydrocarbons, halogenated hydrocarbons and oxygenated VOCs. The concentrations of VOCs (ρ(VOCs)) generated at different stages of the coking process are significantly different. ρ(VOCs) from coke oven chimney had the highest concentration (87.1 mg/m3), followed by coke pushing (4.0 mg/m3), coal charging (3.3 mg/m3) and coke oven tops (1.1 mg/m3). VOCs species emitted from the coke production processes were dominated by alkanes and alkenes, but the composition proportions were different at the different stages. Alkenes were the most abundant emission species in flue gases of the coke oven chimney accounting for up to 66% of the total VOCs, while the VOCs emissions from coke pushing and coal charging were dominated by alkanes (36% and 42%, respectively), and the alkanes and alkenes emitted from coke oven top were similar (31% and 29%, respectively). Based on above results, reduction of VOCs emissions from coke oven chimney flue gases is suggested to be an effective measure, especially for alkenes.


Assuntos
Poluentes Atmosféricos/análise , Coque , Ozônio/análise , Compostos Orgânicos Voláteis/análise , China , Monitoramento Ambiental
15.
J Environ Sci (China) ; 95: 256-265, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32653188

RESUMO

Atmospheric carbonyls were measured at a typical rural area of the North China Plain (NCP) from November 13 to December 24, 2017 to investigate the pollution characteristics, sources and environmental implications. Fifteen carbonyls were detected, and formaldehyde, acetaldehyde and acetone accounted for about 81% at most. The concentration of the total carbonyls in heavily polluted days was twice more than that in clean days. In contrast to other carbonyls, m-tolualdehyde exhibited relatively high concentrations in the clean days in comparison with the polluted days. The ratios of three principal carbonyls to CO showed similar daily variations at different pollution levels with significant daytime peaks. Multiple linear regression analysis revealed that the contributions of background, primary and secondary sources to three principal carbonyls showed similar variation trends from the clean level to the heavily polluted level. The OH formation rate of formaldehyde showed a similar variation trend to its photodegradation rate, reaching the peak value at noon, which is important to maintain relatively high OH levels to initiate the oxidation of various gas-phase pollutants for secondary pollutant formation at the rural site. OH radical consumption rate and ozone formation potential (OFP) calculations showed that formaldehyde and acetaldehyde were the dominant oxidative species among measured carbonyls. As for OH radical consumption, n-butyraldehyde and m-tolualdehyde were important contributors, while for ozone formation potential, n-butyraldehyde and propionaldehyde made significant contributions. In addition, the contribution of carbonyl compounds to secondary organic aerosol (SOA) formation was also important and needs further investigation.


Assuntos
Poluentes Atmosféricos/análise , Ozônio/análise , China , Monitoramento Ambiental , Estações do Ano
16.
J Environ Sci (China) ; 95: 33-42, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32653190

RESUMO

Vertical profiles of isoprene and monoterpenes were measured by a proton transfer reaction-time of flight-mass spectrometry (PTR-ToF-MS) at heights of 3, 15, 32, 64, and 102 m above the ground on the Institute of Atmospheric Physics (IAP) tower in central Beijing during the winter of 2016 and the summer of 2017. Isoprene mixing ratios were larger in summer due to much stronger local emissions whereas monoterpenes were lower in summer due largely to their consumption by much higher levels of ozone. Isoprene mixing ratios were the highest at the 32 m in summer (1.64 ± 0.66 ppbV) and at 15 m in winter (1.41 ± 0.64 ppbV) with decreasing concentrations to the ground and to the 102 m, indicating emission from the tree canopy of the surrounding parks. Monoterpene mixing ratios were the highest at the 3 m height in both the winter (0.71 ± 0.42 ppbV) and summer (0.16 ± 0.10 ppbV) with a gradual decreasing trend to 102 m, indicting an emission from near the ground level. The lowest isoprene and monoterpene mixing ratios all occurred at 102 m, which were 0.71 ± 0.42 ppbV (winter) and 1.35 ± 0.51 ppbV (summer) for isoprene, and 0.42 ± 0.22 ppbV (winter) and 0.07 ± 0.06 ppbV (summer) for monoterpenes. Isoprene in the summer and monoterpenes in the winter, as observed at the five heights, showed significant mutual correlations. In the winter monoterpenes were positively correlated with combustion tracers CO and acetonitrile at 3 m, suggesting possible anthropogenic sources.


Assuntos
Poluentes Atmosféricos/análise , Ozônio/análise , Compostos Orgânicos Voláteis/análise , Pequim , Monitoramento Ambiental , Monoterpenos/análise
17.
J Environ Sci (China) ; 95: 49-57, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32653192

RESUMO

Mass level of fine particles (PM2.5) in main cities in China has decreased significantly in recent years due to implementation of Chinese Clean Air Action Plan since 2013, however, O3 pollution is getting worse than before, especially in megacities such as in Shanghai. In this work, O3 and PM2.5 were continuously monitored from May 27, 2018 to March 31, 2019. Our data showed that the annual average concentration of PM2.5 and O3 (O3-8 hr, maximum 8-hour moving average of ozone days) was 39.35 ± 35.74 and 86.49 ± 41.65 µg/m3, respectively. The concentrations of PM2.5 showed clear seasonal trends, with higher concentrations in winter (83.36 ± 18.66 µg/m3) and lower concentrations in summer (19.85 ± 7.23 µg/m3), however, the seasonal trends of O3 were different with 103.75 ± 41.77 µg/m3 in summer and 58.59 ± 21.40 µg/m3 in winter. Air mass backward trajectory, analyzing results of potential source contribution function model and concentration weighted trajectory model implied that pollutants from northwestern China contributed significantly to the mass concentration of Shanghai PM2.5, while pollutants from areas of eastern coastal provinces and South China Sea contributed significantly to the mass level of ozone in Shanghai atmosphere. Mass concentration of twenty-one elements in the PM2.5 were investigated, and their relationships with O3 were analyzed. Mass level of ozone had good correlation with that of Ba (r = 0.64, p < 0.05) and V (r = 0.30, p > 0.05), suggesting vehicle emission pollutants contribute to the increasing concentration of ozone in Shanghai atmosphere.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar , Ozônio/análise , Atmosfera , China , Cidades , Monitoramento Ambiental , Material Particulado/análise , Estações do Ano
18.
J Environ Sci (China) ; 95: 58-64, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32653193

RESUMO

Hydroxyl free radicals (OH radicals) play the main role in atmospheric chemistry and their involving reactions are the dominant rate determining step in the formation of secondary fine particulate matter and in the removal of air pollutants from the atmosphere. In this paper, we studied the seasonal variation characteristics of OH radicals during the daytime in Lanzhou and explored the potential formation mechanism of high concentration OH radicals. We found that the OH radicals in four seasons was 2.7 × 106, 2.6 × 106, 3.1 × 106, and 2.2 × 106 cm-3, respectively. Since the rainfall was concentrated in summer, the wet deposition had a significant effect on removing OH radicals. Among the four pollutants (including ozone (O3), volatile organic compounds (VOCs), nitrogen dioxide (NO2) and fine particulate matter (PM2.5)), the variation of OH radicals were closely related to ozone concentration especially in spring and summer. In autumn, the correlation between PM2.5 and OH radicals were the closest among the observing pollutants and its formation mechanism was different conventional regeneration pathway. In Event 1, high concentration of ozone was the main source of OH radicals; under the high humidity condition, except for ozone, the multiple factors including VOCs, NO2 and PM2.5 interplayed and leaded to the Event 2.


Assuntos
Poluentes Atmosféricos/análise , Ozônio/análise , Atmosfera , Monitoramento Ambiental , Radical Hidroxila/análise , Material Particulado/análise , Estações do Ano
19.
Environ Monit Assess ; 192(8): 511, 2020 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-32661736

RESUMO

The observation and analysis of volatile organic compounds (VOCs) were conducted during January 2018 in nine prefecture-level cities of Sichuan, China, covering the period of heavily polluted weather. Air samples collected in nine prefecture-level cities were analyzed using a preconcentration method coupled with GC-MS/FID. The characteristics and ozone generation potential (OFP) of VOCs were analyzed. The relationship between air quality index (AQI) and VOCs and gross domestic product (GDP) and VOCs were also discussed, respectively. The results show that the characteristics of VOCs in cities are highly related to their industrial structure and GDP. Generally, areas with high AQI values are accompanied by high VOC concentrations. Alkanes and halocarbons were the most abundant VOCs in the atmospheric environment in the nine prefecture-level cities, accounting for 24.5~61.6% and 15.6~23.6% of total VOC concentration, respectively. The MIR method was used to analyze the OFP, and olefins contributed the most to ozone formation. Among the nine cities located in Sichuan, Dazhou was found to be the city with the highest OFP value (1191.49 µg/m3).


Assuntos
Poluentes Atmosféricos/análise , Ozônio/análise , Compostos Orgânicos Voláteis/análise , China , Cidades , Monitoramento Ambiental
20.
Environ Monit Assess ; 192(8): 496, 2020 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-32643033

RESUMO

Ground-level ozone is the primary source of air pollution in China, particularly during the warmer months. In this study, we investigated the exposure status of ozone pollution and the temperature distribution in an air-conditioned bus in Jinan during the evening peak period based on field measurements obtained with a handheld portable particle counter and indigo disulfonate spectrophotometry. Statistical analysis showed that the passengers experienced poor air quality within the confines of the bus due to the poor air quality outside. Furthermore, the level of passenger comfort was dissatisfactory because of the high temperature, thereby highlighting the urgent need to improve the current situation. Numerical simulations were conducted using FLUENT software to explore the impacts of the air supply angle, the opening and closing of the bus door, and the chemical reaction between ozone and its precursors on the diffusion and distribution of ozone, the temperature, and the airflow field. The results indicated that high concentrations of ozone were present in the middle and front regions of the bus. Pollution can be reduced by keeping the bus door open for no longer than 20 s when waiting for other passengers, and the best optimization effect in relation to the temperature and passenger comfort was determined as an air supply angle of 30°. In addition, the average individual daily intake of ozone was combined with other relevant parameters to assess the exposure level. It is recommended that the elderly and children should avoid peak time travel to reduce their exposure to ozone (inhalation dose values > 60 µg/m3 and > 56 µg/m3 according to simulations, respectively). These findings are expected to effectively improve the air quality and passenger comfort levels in busses, thereby protecting the health of passengers and reducing carbon usage.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/análise , Ozônio/análise , Idoso , Ar Condicionado , Criança , China , Monitoramento Ambiental , Humanos , Veículos Automotores
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