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2.
Environ Pollut ; 254(Pt A): 113030, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31554141

RESUMO

BACKGROUND: Conjunctivitis has hazardous effects on patients' quality of life through influencing school performance, work productivity, and daily activities such as driving. However, limited evidence is available on the contributory role of air pollution on conjunctivitis, particularly in China. METHODS: We obtained data of 81,351 conjunctivitis outpatients from the largest comprehensive hospitals of four cities, China, between Jan 1, 2013 and Dec 31, 2014. Data on air pollutants, including particulate matter ≤2.5 µm in diameter (PM2.5), particulate matter ≤10 µm in diameter (PM10), nitrogen dioxide (NO2), ozone (O3) and sulphur dioxide (SO2) were collected from China National Environmental Monitoring Centre. Conjunctivitis outpatient visits were linked with air pollution concentrations by the visiting dates. A time-stratified case-crossover design with conditional logistic regression model was used to examine the effect of short-term exposure to air pollution on conjunctivitis outpatient visits. RESULTS: We found that the associations between air pollutants (per 10 µg/m3 increase) and hospital outpatient visits for asthma were [odds ratios (ORs) and 95% confidence intervals]: 1.004(1.002-1.007) for PM2.5, 1.004 (1.002-1.005) for PM10, 1.012(1.005-1.020) for NO2, 1.006 (1.001-1.011) for SO2, and 1.007 (1.003-1.010) for O3, respectively at lag0 day. Outpatients aged 35-64 years showed significant associations with exposure to PM2.5 (1.005, 1.001-1.010), PM10 (1.005, 1.002-1.008), NO2 (1.014, 1.003-1.026), and O3 (1.005, 1.000-1.011), while those aged 15-34 years showed significant associations with exposure to O3 (1.010, 1.004-1.017). CONCLUSIONS: Short-term exposure to air pollution has impacts on outpatient visits for conjunctivitis in China. This study suggests that improving air quality could protect eye health.


Assuntos
Poluentes Atmosféricos/toxicidade , Poluição do Ar/análise , Conjuntivite/induzido quimicamente , Conjuntivite/epidemiologia , Material Particulado/toxicidade , Adolescente , Adulto , Idoso , Poluentes Atmosféricos/análise , Asma/epidemiologia , China , Cidades , Estudos Cross-Over , Monitoramento Ambiental/métodos , Humanos , Masculino , Pessoa de Meia-Idade , Dióxido de Nitrogênio/análise , Dióxido de Nitrogênio/toxicidade , Razão de Chances , Pacientes Ambulatoriais , Ozônio/análise , Ozônio/toxicidade , Material Particulado/análise , Qualidade de Vida , Dióxido de Enxofre/análise , Dióxido de Enxofre/toxicidade , Adulto Jovem
3.
Environ Pollut ; 254(Pt A): 113010, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31554142

RESUMO

Autism spectrum disorder (ASD) affects more boys than girls. Recent animal studies found that early life exposure to ambient particles caused autism-like behaviors only in males. However, there has been little study of sex-specificity of effects on ASD in humans. We evaluated ASD risk associated with prenatal and first year of life exposures to particulate matter less than 2.5 µm in aerodynamic diameter (PM2.5) by child sex. This retrospective cohort study included 246,420 singleton children born in Kaiser Permanente Southern California (KPSC) hospitals between 1999 and 2009. The cohort was followed from birth through age five to identify 2471 ASD cases from the electronic medical record. Ambient PM2.5 and other regional air pollution measurements (PM less than 10 µm, ozone, nitrogen dioxide) from regulatory air monitoring stations were interpolated to estimate exposure during each trimester and first year of life at each geocoded birth address. Hazard ratios (HRs) were estimated using Cox regression models to adjust for birth year, KPSC medical center service areas, and relevant maternal and child characteristics. Adjusted HRs per 6.5 µg/m3 PM2.5 were elevated during entire pregnancy [1.17 (95% confidence interval (CI), 1.04-1.33)]; first trimester [1.10 (95% CI, 1.02-1.19)]; third trimester [1.08 (1.00-1.18)]; and first year of life [1.21 (95% CI, 1.05-1.40)]. Only the first trimester association remained robust to adjustment for other exposure windows, and was specific to boys only (HR = 1.18; 95% CI, 1.08-1.27); there was no association in girls (HR = 0.90; 95% CI, 0.76-1.07; interaction p-value 0.03). There were no statistically significant associations with other pollutants. PM2.5-associated ASD risk was stronger in boys, consistent with findings from recent animal studies. Further studies are needed to better understand these sexually dimorphic neurodevelopmental associations.


Assuntos
Poluentes Atmosféricos/toxicidade , Poluição do Ar/análise , Transtorno do Espectro Autista/induzido quimicamente , Material Particulado/toxicidade , Poluentes Atmosféricos/análise , California , Criança , Estudos de Coortes , Feminino , Humanos , Masculino , Dióxido de Nitrogênio/análise , Ozônio/análise , Material Particulado/análise , Gravidez , Primeiro Trimestre da Gravidez , Modelos de Riscos Proporcionais , Estudos Retrospectivos , Fatores Sexuais
4.
Photochem Photobiol Sci ; 18(11): 2696-2706, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31556901

RESUMO

The major source of vitamin D in humans is the ultraviolet radiation-dependent cutaneous synthesis of cholecalciferol; however, low vitamin D status is common in Europe even at mid-latitudes. The UV-radiation that reached the Earth's surface near Milan between May 2006 and December 2018 was retrieved from the TEMIS database and matched with the serum vitamin D levels measured in 30 400 people living in the same area. The results showed a high percentage of insufficient vitamin D levels (measured as 25-hydroxy-vitamin D) throughout the years. During the "vitamin D winter" (November-March) up to 60-90% of the population shows deficient/insufficient (<20-30 ng mL-1) levels of vitamin D and it is explained by the difficulty in obtaining the recommended UV vitamin D doses. In contrast, the warm season provides plenty of UV-radiation, but still 30-50% of the population shows deficient/insufficient vitamin D levels. The circannual vitamin D variations were less evident in the female groups which, in the cold season, show values higher than the corresponding male groups. An age group analysis explained this difference by the strongly recommended vitamin D intake for post-menopausal women. In conclusion, increasing the medical advice for vitamin D intake is strongly recommended to improve the vitamin D status at European mid-latitudes. Our findings suggest that UV availability alone cannot explain the vitamin D status of the population which instead is likely to be influenced by several other factors related to both the people's lifestyle and their personal characteristics. A desirable vitamin D range considering the time of the year and sun exposure, but also including factors not related to UV-radiation, would probably result in a more accurate diagnosis of the patients' vitamin D status. Despite the relatively large time interval, no evident effects due to climate changes were observed in the vitamin D levels during the almost 13 years of analysis.


Assuntos
Raios Ultravioleta , Vitamina D/sangue , Europa (Continente) , Feminino , Humanos , Imunoensaio , Estilo de Vida , Masculino , Pessoa de Meia-Idade , Ozônio/análise , Estações do Ano , Vitamina D/análogos & derivados
5.
Environ Pollut ; 252(Pt B): 1863-1871, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31369942

RESUMO

Alternative transportation fuels (ATFs) can reduce air pollution. However, the influence of conventional fuels-diesel and gasoline, and particularly ATFs on photochemical air pollution is not well-characterized, limiting assessments of ATFs and air quality. This is mainly due to frequent use of lumped chemical mechanisms by related atmospheric modeling. Here we hypothesized that applying a chemical mechanism that is specifically developed according to both emission fractions and photochemical ozone creation potential of volatile organic compounds (VOCs) is key to gaining reliable insights into the impact of transportation fuels on photochemistry. We used a heterogeneous chemical mechanism with 927 reactions and relatively detailed emission inventories to specifically meet the requirements for reliable simulation of the effect of exhaust emissions from vehicles fueled by selected model fuels-diesel, gasoline, and mixtures of 15% gasoline with 85% ethanol (E85) or 85% methanol (M85)-on photochemistry. These dispersion-box model simulations revealed a strong influence of atmospheric background balance between VOCs and nitrogen oxides (NOX = [NO] + [NO2]) on the impact of exhaust emissions on photochemistry, with higher tendency toward ozone (O3) formation or destruction for more VOC-limited or NOX-limited conditions, respectively. Accordingly, higher [NOX]/[VOC] exhaust emission, such as from diesel and M85, resulted in lower O3, not only locally but also downwind of the emission. This offers a new perspective and measure for transportation fuel assessment. Rapid conversion of O3 to hydroxyl and hydroperoxyl radicals downwind of the exhaust emission indicates the importance of simulating the impact of road transportation on photochemistry at high spatial and temporal resolution. Peroxyacetyl nitrate formation was more sensitive to VOC emission under VOC-limited conditions than to NOX emission under NOX-limited conditions. Secondary formaldehyde dominated over primary emitted formaldehyde several minutes after emission. These findings should be verified using a 3D modeling study under varying meteorological conditions.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/análise , Gasolina/análise , Óxidos de Nitrogênio/análise , Ozônio/análise , Emissões de Veículos/análise , Radical Hidroxila/análise , Modelos Teóricos , Fotoquímica , Transportes , Compostos Orgânicos Voláteis/análise
6.
Environ Pollut ; 254(Pt A): 112952, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31369913

RESUMO

We have carried out a comprehensive analysis of six air pollutants (particles with an aerodynamic diameter less than 2.5 µm (PM2.5) and less than 10 µm (PM10), carbon monoxide (CO), sulfur dioxide (SO2), nitrogen dioxide (NO2), and ozone (O3)) in western China, including the spatiotemporal characteristics of air pollutants, their relationship with meteorological factors and emission sources, and the efficiency of emission control strategies for the region. Based hourly observations at 23 sites in western China from June 2016 to May 2017, concentrations of most pollutants were higher outside the Tibetan Plateau, lowest in summer and highest in winter, the exception being O3. This was partially because meteorological conditions in winter were found to the most unfavorable to pollutant dispersion and dilution than other seasons. Pollutant concentrations at most sites were correlated with the residential emissions which were higher in winter, but anti-correlated with the industrial emissions which were lower during the winter holiday period. The Weather Research and Forecasting with Chemistry (WRF-Chem) simulations of four pollution control strategies indicated that reduction of residential emissions is crucial to alleviate PM2.5, PM10, and CO pollution in western China, although reduction of industrial and transport emissions can reduce SO2 and NO2, respectively. Since PM2.5 and PM10 were also found to be the species most and next frequently responsible for extremely serious pollution in western China, respectively, we recommend pollution control regulations that target residential emissions.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/estatística & dados numéricos , Poluição do Ar/análise , Monóxido de Carbono/análise , China , Habitação , Conceitos Meteorológicos , Meteorologia , Dióxido de Nitrogênio/análise , Ozônio/análise , Material Particulado/análise , Estações do Ano , Dióxido de Enxofre/análise , Tempo (Meteorologia)
7.
Environ Pollut ; 254(Pt B): 113036, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31465899

RESUMO

Ambient air pollution (AAP) is recognized a cardiovascular risk factor and lipid profile dysregulation seems to be one of the potential mediators involved. However, results from epidemiologic research on the association between exposure to AAP and altered lipid profile have been inconsistent. This study aims to systematically review and meta-analyse epidemiologic evidence on the association between exposure to ambient air pollutants (particulate matter, nitrogen oxides, sulphur dioxide, ozone, carbon monoxide, back carbon) and lipid profile parameters (Total cholesterol; High-Density Lipoprotein Cholesterol; Low-Density Lipoprotein Cholesterol; TG-Triglycerides) or dyslipidaemia. Systematic electronic literature search was performed in PubMed, Web of Science and Scopus databases (last search on 24th May 2019) using keywords related to the exposure (ambient air pollutants) and to the outcomes (lipid profile parameters/dyslipidaemia). Qualitative and quantitative information of the studies were extracted and fixed or random-effects models were used to obtain a pooled effect estimate per each pollutant/outcome combination. 22 studies were qualitatively analysed and, from those, 3 studies were quantitatively analysed. Particulate matters were the most studied pollutants and a considerable heterogeneity in air pollution assessment methods and outcomes definitions was detected. Age, obesity related measures, tobacco consumption, sex and socioeconomic factors were the most frequent considered variables for confounding adjustment in the models. In a long-term exposure scenario, we found a 3.14% (1.36%-4.95%) increase in TG levels per 10 µg/m3 PM10 increment and a 4.24% (1.37%-7.19%) increase in TG levels per 10 µg/m3 NO2 increment. No significant associations were detected for the remaining pollutant/outcome combinations. Despite the few studies included in the meta-analysis, our study suggests some epidemiologic evidence supporting the association between PM10 and NO2 exposures and increased TG levels. Due to the very low level of evidence, more studies are needed to clarify the role of lipid profile dysregulation as a mediator on the AAP adverse cardiovascular effects.


Assuntos
Poluição do Ar/estatística & dados numéricos , Exposição Ambiental/análise , Lipídeos/análise , Poluentes Atmosféricos/análise , Poluição do Ar/análise , Monóxido de Carbono/análise , Poluentes Ambientais/análise , Feminino , Humanos , Masculino , Óxidos de Nitrogênio/análise , Ozônio/análise , Material Particulado/análise , Fatores Socioeconômicos , Dióxido de Enxofre/análise
8.
JAMA ; 322(6): 546-556, 2019 08 13.
Artigo em Inglês | MEDLINE | ID: mdl-31408135

RESUMO

Importance: While air pollutants at historical levels have been associated with cardiovascular and respiratory diseases, it is not known whether exposure to contemporary air pollutant concentrations is associated with progression of emphysema. Objective: To assess the longitudinal association of ambient ozone (O3), fine particulate matter (PM2.5), oxides of nitrogen (NOx), and black carbon exposure with change in percent emphysema assessed via computed tomographic (CT) imaging and lung function. Design, Setting, and Participants: This cohort study included participants from the Multi-Ethnic Study of Atherosclerosis (MESA) Air and Lung Studies conducted in 6 metropolitan regions of the United States, which included 6814 adults aged 45 to 84 years recruited between July 2000 and August 2002, and an additional 257 participants recruited from February 2005 to May 2007, with follow-up through November 2018. Exposures: Residence-specific air pollutant concentrations (O3, PM2.5, NOx, and black carbon) were estimated by validated spatiotemporal models incorporating cohort-specific monitoring, determined from 1999 through the end of follow-up. Main Outcomes and Measures: Percent emphysema, defined as the percent of lung pixels less than -950 Hounsfield units, was assessed up to 5 times per participant via cardiac CT scan (2000-2007) and equivalent regions on lung CT scans (2010-2018). Spirometry was performed up to 3 times per participant (2004-2018). Results: Among 7071 study participants (mean [range] age at recruitment, 60 [45-84] years; 3330 [47.1%] were men), 5780 were assigned outdoor residential air pollution concentrations in the year of their baseline examination and during the follow-up period and had at least 1 follow-up CT scan, and 2772 had at least 1 follow-up spirometric assessment, over a median of 10 years. Median percent emphysema was 3% at baseline and increased a mean of 0.58 percentage points per 10 years. Mean ambient concentrations of PM2.5 and NOx, but not O3, decreased substantially during follow-up. Ambient concentrations of O3, PM2.5, NOx, and black carbon at study baseline were significantly associated with greater increases in percent emphysema per 10 years (O3: 0.13 per 3 parts per billion [95% CI, 0.03-0.24]; PM2.5: 0.11 per 2 µg/m3 [95% CI, 0.03-0.19]; NOx: 0.06 per 10 parts per billion [95% CI, 0.01-0.12]; black carbon: 0.10 per 0.2 µg/m3 [95% CI, 0.01-0.18]). Ambient O3 and NOx concentrations, but not PM2.5 concentrations, during follow-up were also significantly associated with greater increases in percent emphysema. Ambient O3 concentrations, but not other pollutants, at baseline and during follow-up were significantly associated with a greater decline in forced expiratory volume in 1 second per 10 years (baseline: 13.41 mL per 3 parts per billion [95% CI, 0.7-26.1]; follow-up: 18.15 mL per 3 parts per billion [95% CI, 1.59-34.71]). Conclusions and Relevance: In this cohort study conducted between 2000 and 2018 in 6 US metropolitan regions, long-term exposure to ambient air pollutants was significantly associated with increasing emphysema assessed quantitatively using CT imaging and lung function.


Assuntos
Poluentes Atmosféricos/efeitos adversos , Poluição do Ar/efeitos adversos , Pulmão/fisiologia , Enfisema Pulmonar , Idoso , Idoso de 80 Anos ou mais , Poluentes Atmosféricos/análise , Poluição do Ar/análise , Carbono/efeitos adversos , Carbono/análise , Estudos de Coortes , Progressão da Doença , Exposição Ambiental/efeitos adversos , Feminino , Humanos , Pulmão/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Óxidos de Nitrogênio/efeitos adversos , Óxidos de Nitrogênio/análise , Ozônio/efeitos adversos , Ozônio/análise , Material Particulado/efeitos adversos , Material Particulado/análise , Enfisema Pulmonar/epidemiologia , Enfisema Pulmonar/fisiopatologia , Testes de Função Respiratória , Tomografia Computadorizada por Raios X , Estados Unidos/epidemiologia
9.
Sci Total Environ ; 691: 516-527, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31325852

RESUMO

European standards for the protection of forests from ozone (O3) are based on atmospheric exposure (AOT40) that is not always representative of O3 effects since it is not a proxy of gas uptake through stomata (stomatal flux). MOTTLES "MOnitoring ozone injury for seTTing new critical LEvelS" is a LIFE project aimed at establishing a permanent network of forest sites based on active O3 monitoring at remote areas at high and medium risk of O3 injury, in order to define new standards based on stomatal flux, i.e. PODY (Phytotoxic Ozone Dose above a threshold Y of uptake). Based on the first year of data collected at MOTTLES sites, we describe the MOTTLES monitoring station, together with protocols and metric calculation methods. AOT40 and PODY, computed with different methods, are then compared and correlated with forest-health indicators (radial growth, crown defoliation, visible foliar O3 injury). For the year 2017, the average AOT40 calculated according to the European Directive was even 5 times (on average 1.7 times) the European legislative standard for the protection of forests. When the metrics were calculated according to the European protocols (EU Directive 2008/50/EC or Modelling and Mapping Manual LTRAP Convention), the values were well correlated to those obtained on the basis of the real duration of the growing season (i.e. MOTTLES method) and were thus representative of the actual exposure/flux. AOT40 showed opposite direction relative to PODY. Visible foliar O3 injury appeared as the best forest-health indicator for O3 under field conditions and was more frequently detected at forest edge than inside the forest. The present work may help the set-up of further long-term forest monitoring sites dedicated to O3 assessment in forests, especially because flux-based assessments are recommended as part of monitoring air pollution impacts on ecosystems in the revised EU National Emissions Ceilings Directive.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/estatística & dados numéricos , Monitoramento Ambiental/métodos , Ozônio/análise , Conservação dos Recursos Naturais , Ecossistema , Agricultura Florestal , Florestas , Estômatos de Plantas
10.
Sci Total Environ ; 691: 549-561, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31325855

RESUMO

BACKGROUND: Mounting evidence suggests that short-term exposure to ozone increases the risk of asthma exacerbations. However, ozone exposures have been assessed using ambient ozone concentrations averaged over different time periods in different studies. OBJECTIVE: To evaluate the risks for asthma exacerbations related to ambient ozone measured as 1-hour or 8-hour daily maximum and 24-hour average concentrations. METHODS: Based on a literature search in PubMed, EMBASE and Web of Science, we identified all time-series studies as of December 4th, 2018 and included 47 eligible studies in our analyses. Asthma exacerbation is defined as the risk for emergency room visits or hospital admissions. Pooled relative risks (RRs) and 95% confidence intervals (95%CIs) for a 10 µg/m3 increase in daily ozone concentration were estimated using random effect models. Subgroup analyses and sensitivity analyses were also performed to examine the risks for different seasons, regions and age groups and for the robustness of our main findings. RESULTS: Significant and similar associations were found for O3-1 h max (RR,1.012; 95%CI, 1.005-1.019) and O3-8 h max (RR, 1.011; 95%CI, 1.007-1.014), while marginal effect was identified for O3-24 h average (RR, 1.005; 95%CI, 0.996-1.014). No significant publication bias but high heterogeneities were observed. During the warm season, ozone was significantly associated with asthma exacerbation. O3-1 h max had the highest RR of 1.014 (95%CI, 1.005-1.024), followed by O3-8 h max (RR, 1.012; 95%CI, 1.009-1.016), while marginal association was identified for O3-24 h avg (RR, 1.008; 95%CI, 0.998-1.017). During the cold season, null associations were identified for all the three averaging times. Variations were also observed in region and age. CONCLUSION: Ozone exposure measured as 1-hour or 8-hour daily max were more consistently associated with asthma exacerbations than 24-hour average exposure during the warm season.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/estatística & dados numéricos , Asma/epidemiologia , Exposição por Inalação/estatística & dados numéricos , Ozônio/análise , Monitoramento Ambiental , Humanos
11.
Ecotoxicol Environ Saf ; 182: 109404, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31310902

RESUMO

Increasing tropospheric ozone (O3) concentrations in most regions of the world have led to significant phytotoxicity to all types of vegetation. Indo-Gangetic Plains of India is one of the hot spot areas with high O3 concentrations throughout the year although O3 phytotoxicity on grassland species in this region is not explored. Therefore the present study was conducted to assess the responses of a dominant species, Ischaemum rugosum Salisb, a C4 grass and a co-dominant species Malvastrum coromandelianum (L.) Garcke, a C3 forb under future elevated O3 (non filtered ambient + 20 nl l-1; NFA+) concentration compared to non filtered ambient (NFA; 48.7 nl l-1, 8 h mean) for 9 weeks from 15th May to 15th July 2016 in mix-culture using open-top chambers (OTCs). Plants were assessed for physiological, biochemical and growth parameters including biomass accumulation during vegetative and reproductive stages to assess the O3 induced responses. Under NFA+, higher reductions were observed in physiological parameters, growth and total biomass accumulation in M. coromandelianum compared to I. rugosum while both the species suffered membrane damage. Enhancement in contents of ascorbic acid and tannin in I. rugosum while proline and total phenolics in M. coromandelianum led to more protection of former species compared to later from oxidative damage. No significant change in stomatal conductance in I. rugosum while significant increase in M. coromandelianum might have led to more accumulation of O3 inside the plant, thus more negatively affecting the performance of later species. The present study concludes that M. coromandelianum (C3 photosynthetic pathway) will be relatively more negatively affected compared to I. rugosum (C4 photosynthetic pathway) under future O3 concentrations.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Ozônio/análise , Poaceae/crescimento & desenvolvimento , Poluentes Atmosféricos/toxicidade , Biomassa , Pradaria , Índia , Ozônio/toxicidade , Fotossíntese/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/crescimento & desenvolvimento , Poaceae/efeitos dos fármacos
12.
Environ Pollut ; 253: 130-140, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31306820

RESUMO

Skin cancer is the most common type of cancer in the United States, the majority of which is caused by overexposure to ultraviolet (UV) irradiance, which is one component of sunlight. National Environmental Public Health Tracking Program at CDC has collaborated with partners to develop and disseminate county-level daily UV irradiance (2005-2015) and total solar irradiance (1991-2012) data for the contiguous United States. UV irradiance dataset was derived from the Ozone Monitoring Instrument (OMI), and solar irradiance was extracted from National Solar Radiation Data Base (NSRDB) and SolarAnywhere data. Firstly, we produced daily population-weighted UV and solar irradiance datasets at the county level. Then the spatial distributions and long-term trends of UV irradiance, solar irradiance and the ratio of UV irradiance to solar irradiance were analyzed. The national average values across all years are 4300 Wh/m2, 2700 J/m2 and 130 mW/m2 for global horizontal irradiance (GHI), erythemally weighted daily dose of UV irradiance (EDD) and erythemally weighted UV irradiance at local solar noon time (EDR), respectively. Solar, UV irradiances and the ratio of UV to solar irradiance all increased toward the South and in some areas with high altitude, suggesting that using solar irradiance as indicator of UV irradiance in studies covering large geographic regions may bias the true pattern of UV exposure. National annual average daily solar and UV irradiances increased significantly over the years by about 0.3% and 0.5% per year, respectively. Both datasets are available to the public through CDC's Tracking network. The UV irradiance dataset is currently the only publicly-available, spatially-resolved, and long-term UV irradiance dataset covering the contiguous United States. These datasets help us understand the spatial distributions and temporal trends of solar and UV irradiances, and allow for improved characterization of UV and sunlight exposure in future studies.


Assuntos
Energia Solar , Raios Ultravioleta , Exposição Ambiental , Humanos , Ozônio/análise , Neoplasias Cutâneas , Análise Espaço-Temporal , Luz Solar , Estados Unidos
13.
Environ Pollut ; 253: 821-830, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31344543

RESUMO

Nitrogen deposition and tropospheric ozone are important drivers of vegetation damage, but their interactive effects are poorly understood. This study assessed whether long-term nitrogen deposition altered sensitivity to ozone in a semi-natural vegetation community. Mesocosms were collected from sand dune grassland in the UK along a nitrogen gradient (5-25 kg N/ha/y, including two plots from a long-term experiment), and fumigated for 2.5 months to simulate medium and high ozone exposure. Ozone damage to leaves was quantified for 20 ozone-sensitive species. Soil solution dissolved organic carbon (DOC) and soil extracellular enzymes were measured to investigate secondary effects on soil processes. Mesocosms from sites receiving the highest N deposition showed the least ozone-related leaf damage, while those from the least N-polluted sites were the most damaged by ozone. This was due to differences in community-level sensitivity, rather than species-level impacts. The N-polluted sites contained fewer ozone-sensitive forbs and sedges, and a higher proportion of comparatively ozone-resistant grasses. This difference in the vegetation composition of mesocosms in relation to N deposition conveyed differential resilience to ozone. Mesocosms in the highest ozone treatment showed elevated soil solution DOC with increasing site N deposition. This suggests that, despite showing relatively little leaf damage, the 'ozone resilient' vegetation community may still sustain physiological damage through reduced capacity to assimilate photosynthate, with its subsequent loss as DOC through the roots into the soil. We conclude that for dune grassland habitats, the regions of highest risk to ozone exposure are those that have received the lowest level of long-term nitrogen deposition. This highlights the importance of considering community- and ecosystem-scale impacts of pollutants in addition to impacts on individual species. It also underscores the need for protection of 'clean' habitats from air pollution and other environmental stressors.


Assuntos
Poluição do Ar/estatística & dados numéricos , Monitoramento Ambiental , Pradaria , Nitrogênio/análise , Ozônio/análise , Carex (Planta) , Ecossistema , Poaceae , Solo
14.
Environ Sci Process Impacts ; 21(8): 1393-1402, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31322150

RESUMO

The hydroxyl radical (OH) is one of the most important oxidants controlling the oxidation capacity of the indoor atmosphere. One of the main OH sources indoors is the photolysis of nitrous acid (HONO). In this study, real-time measurements of HONO, nitrogen oxides (NOx) and ozone (O3) in an indoor environment in Guangzhou, China, were performed under two different conditions: (1) in the absence of any human activity and (2) in the presence of cooking. The maximum NOx and HONO levels drastically increased from 15 and 4 ppb in the absence of human activity to 135 and 40 ppb during the cooking event, respectively. The photon flux was determined for the sunlit room, which has a closed south-east oriented window. The photon flux was used to estimate the photolysis rate constants of NO2, J(NO2), and HONO, J(HONO), which span the range between 8 × 10-5 and 1.5 × 10-5 s-1 in the morning from 9:30 to 11:45, and 8.5 × 10-4 and 1.5 × 10-4 s-1 at noon, respectively. The OH concentrations calculated by photostationary state (PSS) approach, observed around noon, are very similar, i.e., 2.4 × 106 and 3.1 × 106 cm-3 in the absence of human activity and during cooking, respectively. These results suggest that under "high NOx" conditions (NOx higher than a few ppb) and with direct sunlight in the room, the NOx and HONO chemistry would be similar, independent of the geographic location of the indoor environment, which facilitates future modeling studies focused on indoor gas phase oxidation capacity.


Assuntos
Poluição do Ar em Ambientes Fechados/análise , Radical Hidroxila/análise , Óxidos de Nitrogênio/análise , Ácido Nitroso/análise , Ozônio/análise , Fotólise , China , Culinária , Humanos , Modelos Teóricos , Ácido Nitroso/efeitos da radiação , Oxirredução , Ozônio/efeitos da radiação , Luz Solar
15.
Environ Pollut ; 253: 393-402, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31325884

RESUMO

In recent years, the concentration of fine particulate matter has decreased gradually in the Pearl River Delta (PRD) region, but the ozone (O3) concentration remains high and has become the primary air pollutant. In this study, using a three-dimensional numerical model [nested air quality prediction modeling system (NAQPMS)] coupled with an on-line source apportionment module, the contribution of different source regions and source categories to the O3 concentration in the PRD region was quantified. A comparison with observation data confirmed that the NAQPMS adequately reproduced surface O3 concentrations in different seasons. Compared with biogenic emissions, anthropogenic precursors play a dominant role in O3 production. In Guangzhou city, among different source categories, mobile emission is the largest contributor (accounting for approximately 40%), followed by industry emissions (20%-24%). Regional control measures for solvent use and mobile emissions are effective for reducing O3 concentration. In the PRD region, self-contribution is more significant in daytime (∼40%) than in nighttime (∼10%) on average. Among the source regions outside PRD, the northern part of Guangdong province, Jiangxi province, and Fujian province are important contributors. Within the PRD region, the self-contribution of each city increases by 12%-32% during O3 episodes (>80 ppbv) compared with the annual mean contribution. The contribution of the entire PRD region and the entire Guangdong province is 46%-63% and 63%-74% in PRD cities during O3 episodes. These results indicate that regional collaboration on emission control within PRD or Guangdong province is effective for reducing O3 episodes in the PRD region. In addition, because long-range transport from regions outside Guangdong province played an important role in the O3 concentration in the PRD region, long-term emission control measures throughout China in subsequent years should be propitious to further reduce the annual O3 level and improve air quality in the PRD region.


Assuntos
Poluentes Atmosféricos/sangue , Monitoramento Ambiental/métodos , Modelos Químicos , Ozônio/análise , Poluentes Atmosféricos/análise , Poluição do Ar , China , Cidades , Indústrias , Modelos Teóricos , Material Particulado/análise , Rios , Estações do Ano
16.
Environ Pollut ; 252(Pt B): 1910-1919, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31227349

RESUMO

Peroxyacetyl nitrate (PAN) is an important reservoir of atmospheric nitrogen, modulating reactive nitrogen cycle and ozone (O3) formation. To understand the origins of PAN, a field measurement was conducted at Tung Chung site (TC) in suburban Hong Kong from October to November 2016. The average level of PAN was 0.63 ±â€¯0.05 ppbv, with a maximum of 7.30 ppbv. Higher PAN/O3 ratio (0.043-0.058) was captured on episodes, i.e. when hourly maximum O3 exceeded 80 ppbv, than on non-episodes (0.01), since O3 production was less efficient than PAN when there was an elevation of precursors (i.e. volatile organic compounds (VOCs) and nitrogen oxide (NOx)). Model simulations revealed that oxidations of acetaldehyde (65.3 ±â€¯2.3%), methylglyoxal (MGLY, 12.7 ±â€¯1.2%) and other oxygenated VOCs (OVOCs) (8.0 ±â€¯0.6%), and radical cycling (12.2 ±â€¯0.8%) were the major production pathways of peroxyacetyl (PA) radical, while local PAN formation was controlled by both VOCs and nitrogen dioxide (NO2). Among all VOC species, carbonyls made the highest contribution (59%) to PAN formation, followed by aromatics (26%) and biogenic VOCs (BVOCs) (10%) through direct oxidation/decomposition. Besides, active VOCs (i.e. carbonyls, aromatics, BVOCs and alkenes/alkynes) could stimulate hydroxyl (OH) production, thus indirectly facilitating the PAN formation. Apart from primary emissions, carbonyls were also generated from oxidation of first-generation precursors, i.e., hydrocarbons, of which xylenes contributed the most to PAN production. Furthermore, PAN formation suppressed local O3 formation at a rate of 2.84 ppbv/ppbv, when NO2, OH and hydroperoxy (HO2) levels decreased and nitrogen monoxide (NO) value enhanced. Namely, O3 was reduced by 2.84 ppbv per ppbv PAN formation. Net O3 production rate was weakened (∼36%) due to PAN photochemistry, so as each individual production and loss pathway. The findings advanced our knowledge of atmospheric PAN and its impact on O3 production.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental , Poluição Ambiental/análise , Ozônio/análise , Ácido Peracético/análogos & derivados , Compostos Orgânicos Voláteis/análise , Acetaldeído/química , Hong Kong , Hidrocarbonetos/análise , Radical Hidroxila/análise , Óxidos de Nitrogênio/análise , Oxirredução , Ácido Peracético/análise , Fotoquímica , Aldeído Pirúvico/química , Xilenos/análise
17.
Environ Sci Process Impacts ; 21(8): 1229-1239, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31173015

RESUMO

The chemistry of oxidants and their precursors (oxidants*) plays a central role in outdoor environments but its importance in indoor air remains poorly understood. Ozone (O3) chemistry is important in some indoor environments and, until recently, ozone was thought to be the dominant oxidant indoors. There is now evidence that formation of the hydroxyl radical by photolysis of nitrous acid (HONO) and formaldehyde (HCHO) may be important indoors. In the past few years, high time-resolution measurements of oxidants* indoors have become more common and the importance of event-based release of oxidants* during activities such as cleaning has been proposed. Here we review the current understanding of oxidants* indoors, including drivers of the formation and loss of oxidants*, levels of oxidants* in indoor environments, and important directions for future research.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar em Ambientes Fechados/análise , Radical Hidroxila/análise , Iluminação , Oxidantes , Fotólise , Poluentes Atmosféricos/efeitos da radiação , Formaldeído/análise , Formaldeído/efeitos da radiação , Radical Hidroxila/efeitos da radiação , Ácido Nitroso/análise , Ácido Nitroso/efeitos da radiação , Ozônio/análise , Ozônio/efeitos da radiação
18.
Environ Sci Process Impacts ; 21(8): 1374-1383, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31225544

RESUMO

Understanding the oxidizing environment indoors is important for predicting indoor air quality and its impact on human health. We made continuous time-resolved measurements (30 s) of several oxidants and oxidant precursors (collectively referred to as oxidant*): ozone (O3), nitric oxide (NO), and NO2* - the sum of nitrogen dioxide (NO2) and nitrous acid (HONO). These species were measured in three indoor environments - an occupied residence, a chemistry laboratory, and an academic office - in Syracuse, New York, during two seasons in 2017 and 2018. Oxidant* levels differed greatly between the residence, the lab and the office. Indoor-to-outdoor ratios (I/O) of O3 were 0.03 and 0.67 in the residence and office; I/ONO (I/ONO2*) were 11.70 (1.26) in the residence and 0.13 (1.70) in the office. Little seasonal variability was observed in the lab and office, but O3 and NO2* levels in the residence were greater in spring than in winter, while NO levels were lower. Human activities such as cooking and opening patio doors resulted in large changes in oxidant* mixing ratios in the residence. In situ chamber experiments demonstrated that the increase in O3 and NO2* levels during door-open periods was due to a combination of physical mixing between indoor and outdoor air, gas-phase production of NO2 from O3-NO chemistry, and heterogeneous formation of HONO on indoor surfaces. Our results also highlight the importance of chemistry (with NO, alkenes, and surfaces) in O3 mixing ratios in the residence, especially during door-open periods.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar em Ambientes Fechados/análise , Habitação/normas , Óxidos de Nitrogênio/análise , Ozônio/análise , Estações do Ano , Culinária , Humanos , New York
19.
Environ Sci Pollut Res Int ; 26(23): 23524-23541, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31203549

RESUMO

The densely populated Greater Cairo (GC) region suffers from severe air quality issues caused by high levels of anthropogenic activities, such as motorized traffic, industries, and agricultural biomass burning events, along with natural sources of particulate matter, such as wind erosion of arid surfaces. Surface-measured concentrations of particulate matter (PM10), sulfur dioxide (SO2), and ozone (O3) and its precursor's gases (nitrogen dioxide, NO2; carbon monoxide, CO) were obtained for the GC region. The PM10 concentrations were found to exceed remarkably the Egyptian guidelines (150 µg/m3). These high levels of PM10 were recorded throughout 68% of the period of measurement in some industrial areas (El-Kolaly). The measured data of pollutants were used for both the evaluation of environmental pollution levels and the validation of the online-integrated regional climate chemistry model "RegCM-CHEM4." Calculation of the bias between the model results and the measured data was used to evaluate the model performance in order to assess its ability in reproducing the chemical species over the area. The model was found to reproduce the seasonal cycle of the pollutants successfully, but with a large underestimation of the PM10 values. Validation of the RegCM-CHEM4 indicated that the emission inventories of mobile sources and anthropogenic activities need to be improved especially with respect to local and regional activities in order to enhance air quality simulations over the GC region.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/estatística & dados numéricos , Monitoramento Ambiental/métodos , Modelos Químicos , Poluição do Ar/análise , Monóxido de Carbono/análise , Cidades , Egito , Indústrias , Dióxido de Nitrogênio/análise , Ozônio/análise , Material Particulado/análise , Dióxido de Enxofre/análise , Vento
20.
Environ Pollut ; 251: 885-891, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31234254

RESUMO

Guangdong Province, which is located in southern China, has a tropical climate with high temperatures and humidity, making it extremely unfavourable for the corrosion resistance of various materials. Meanwhile, as a quickly developing region in China, Guangdong Province is also facing multi-pollutant conditions, which seriously affect the atmospheric degradation of the materials in this region. It is therefore necessary to identify the key air pollutants that affect the atmospheric corrosivity of Guangdong Province and to propose targets of air pollutant control. An analysis of the environmental data and corrosion rates in Guangdong Province showed that the atmospheric corrosivity of the entire region is closely related to the presence of sulfur dioxide (SO2) and ozone (O3). In addition, a superposition model was utilised to reflect the synergistic effect of SO2 and O3, and a superimposed map of both pollutants was drawn to demonstrate their amount. To control the corrosion rate of carbon steel and avoid exceeding the C2 classification in ISO 9223, the following targets of air pollutant control are proposed: an SO2 concentration of lower than 10 µg m-3 and an O3 level of lower than 85 µg m-3.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/análise , Monitoramento Ambiental/métodos , Ozônio/análise , Dióxido de Enxofre/análise , China , Corrosão , Temperatura Alta , Umidade , Dióxido de Nitrogênio/análise , Material Particulado/análise
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