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1.
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
2.
Ying Yong Sheng Tai Xue Bao ; 30(7): 2447-2456, 2019 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-31418248

RESUMO

The static chamber-gas chromatography method was applied to observe CO2 fluxes across the water-air interface from different aquaculture systems, including four groups of mesocosms, i.e., blank control system (CK), monoculture system of Sebastes schlegelii (F), monoculture system of Chlamys farreri (B) and polyculture system of S. schlegelii and C. farreri (FB). Meanwhile, the physical, chemical and biological indices of the water were measured. The results showed that the group CK was a stable CO2 source, with the mean flux of 12.42 mg·m-2·h-1. The group B was a CO2 source during the early and middle periods of the experiment and a CO2 sink at the end of the experiment, with the mean flux during the experiment being 10.95 mg·m-2·h-1. The change trends of CO2 flux in the group F and FB were generally consistent, acting as CO2 sources in the early period and as CO2 sinks subsequently. The mean fluxes of those two groups during the expe-riment were -3.53 and -10.49 mg·m-2·h-1, respectively. Water pH was a good predictor for CO2 flux across the water-air interface according to the result of regression analysis, with pH value of 8.25 as the critical threshold between efflux and influx. The net primary production of water column was the main factor influencing the CO2 flux, indicating that phytoplankton might be the main internal force regulating the CO2 flux across the water-air interface. Our results indicated that C. farreri at present stocking density in the polyculture system could promote phytoplankton biomass as well as primary production and therefore enhance the CO2 sink function.


Assuntos
Poluentes Atmosféricos/análise , Aquicultura , Dióxido de Carbono/análise , Pectinidae , Animais , Metano , Água
4.
Ying Yong Sheng Tai Xue Bao ; 30(6): 1847-1853, 2019 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-31257755

RESUMO

Ammonium salts, including ammonium nitrate, ammonium sulfate and ammonium hydrogen sulfate, are the main components of secondary inorganic aerosols and play an important role in the formation of haze events. The sources and transformation processes of atmospheric ammonium have received more and more attention. In this study, we modified the previous stable isotope analysis technique by improving the injection volume and adding a pH adjustment step, which gave a rapid and accurate measurement of ammonium nitrogen isotope ratio in atmospheric aerosol samples. Firstly, we added alkaline hypobromite to the extracted solution of the atmospheric aerosol filter samples (0.25 µg·mL-1 ammonium nitrogen in 4 mL) to oxidize ammonium (NH4+) to nitrite (NO2-). Then, after adjusting the pH, nitrite (NO2-) was reduced to nitrous oxide (N2O) by hydroxylamine hydrochloride under pH <0.3. Finally, nitrous oxide (N2O) was analyzed by Precon-GasBench-IRMS system to measure ammonium nitrogen isotope ratio. Our approach required low amount of NH4+ and avoided the use of highly toxic and explosive reagents. Meanwhile, the precision of our method could reach as high as 0.2‰ (n=10). This method could increase the NH4+ reduction efficiency to 100% at a condition of pH <0.3 and satisfy the demands of precision and accuracy for determination of ammonium nitrogen isotope in atmospheric aerosol samples. This method would help us better understand the sources, evolutions, chemical and deposition processes of atmospheric ammonium.


Assuntos
Poluentes Atmosféricos/análise , Compostos de Amônio/análise , Monitoramento Ambiental , Hidroxilamina/química , Isótopos de Nitrogênio/análise , Nitrogênio , Oxirredução , Sais
5.
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
6.
Sci Total Environ ; 690: 361-369, 2019 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-31299570

RESUMO

Thinning plays a major role in forest soil carbon cycling. However, the mechanisms governing soil C fluxes, i.e., C input through litterfall and fine root (FR) production and C output through soil heterotrophic respiration (Rh), remain unclear. To fill this gap, we quantified the C fluxes in the topsoil layer (0-20 cm) by measuring litterfall, FR production and total soil respiration (Rs) (Ra (autotrophic respiration) and Rh) at three thinning intensities (control; low-intensity thinning: extraction of 30% of individual trees; high-intensity thinning (HIT): extraction of 70% of individual trees) in a 26-year-old Chinese fir plantation in southern China. In the control plots, the total C input (110 g C m-2 year-1) via litterfall (59 g C m-2 year-1) and FR production (51 g C m-2 year-1) was much lower than the C output via Rh (518 g C m-2 year-1). This finding demonstrated that the soil is a C source (407 g C m-2 year-1). Furthermore, the C source increased with increasing thinning intensity, particularly under HIT, due to the decreased litterfall return and increased soil CO2 emissions through Rh; this increase occurred despite the increased C input from FR production. In addition, the C output via Rs significantly increased by 42% under HIT due to the stimulation of Ra and Rh. Consequently, thinning reduced the topsoil C pool by 7-8%. Redundancy analysis indicated that the soil C fluxes following thinning were driven by increased FR mortality, understory plant biomass and diversity, and microbial biomass carbon (MBC). Overall, our results indicate that heavy thinning increases soil C loss by increasing soil CO2 emissions and decreasing litterfall return, even under substantially increased FR production. This finding suggests that thinning practices should consider the trade-off between soil C inputs and outputs to reduce the impact of thinning on forest soil carbon sequestration.


Assuntos
Poluentes Atmosféricos/análise , Dióxido de Carbono/análise , Agricultura , Carbono/análise , Ciclo do Carbono , Sequestro de Carbono , China , Cunninghamia , Agricultura Florestal , Florestas , Solo , Árvores
7.
Sci Total Environ ; 690: 426-437, 2019 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-31299575

RESUMO

The rapid environmental changes in Australia prompt a more thorough investigation of the influence of transportation, local emissions, and optical-chemical properties on aerosol production across the region. A month-long intensive measurement campaign was conducted during spring 2016 at Mission Beach, a remote coastal site west of the Great Barrier Reef (GBR) on the north-east coast of Australia. One aerosol pollution episode was investigated in early October. This event was governed by meteorological conditions and characterized by the increase in black carbon (BC) mass concentration (averaged value of 0.35 ±â€¯0.20 µg m-3). Under the influence of the continental transportation, a new layer of nucleation-mode aerosols with an initial size diameter of 20 nm was observed and aerosol number concentrations reached the peak of 6733 cm-3 at a diameter of 29 nm. The averaged aerosol extinction coefficient at the height of 2 km was 150 Mm-1, with a small depolarized ratio (3.5-5%). Simultaneously, the boundary layer height presented a fall-rise trend in the presence of these enhanced aerosol concentrations and became stable in a later stage of the episode. We did not observe clear boundary layer height diurnal variations from the LiDAR observations or from the Weather Research and Forecasting (WRF) model outputs, except in an earlier stage of the aerosol episode for the former. Although the sea breeze may have been responsible for these particles, on the balance of available data, we suggest that the aerosol properties at the GBR surface during this period are more likely influenced by regional transportation of continental sources, including biomass-burning aerosols.


Assuntos
Aerossóis/análise , Poluentes Atmosféricos/análise , Recifes de Corais , Monitoramento Ambiental , Austrália , Meteorologia , Modelos Teóricos , Tempo (Meteorologia)
8.
Sci Total Environ ; 690: 620-628, 2019 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-31301502

RESUMO

For determining setback distances considering multiple air pollutants, a comprehensive study was conducted to simulate the atmospheric dispersion of odour, ammonia (NH3), hydrogen sulfide (H2S), and respirable dust using an US EPA air dispersion model AERMOD for a commercial dairy, broiler, and cage-layer barn in the Canadian Prairies. The simulation was conducted using five years of meteorological data. Setback distances were determined with the input of varying monthly emission rates of all four air pollutants and odour impact criteria specifically developed for all three odour sources. Results showed the layer barn had the greatest odour impact area (maximum 3023 m for an annual average odour concentration of 0.01 OU m-3) followed by the broiler and dairy barns. Due to the prevailing south wind for all three barns, odour traveled farthest in the north. Using the suggested odour impact criteria by the Government of Saskatchewan defined for all odour sources, maximum setback distances were decreasing from 1941 to 641 m for the layer barn and from 980 to 320 m for the broiler barn along with the increasing of odour concentration (OC) thresholds (1-6 OU m-3), all in the north direction. While for the dairy barn, setback distances were determined only under an OC limit of 1 OU m-3; maximum 205 m in the north and minimum 171 m in the south. Using the newly developed odour impact criteria specifically for the three odour sources, maximum setback distance of 558 m in the north was determined for the layer barn under an odour threshold of 9 OU m-3. Additionally, the results suggest the use of odour impact criteria for determining setback distance rather than using gas/respirable threshold limits set in ambient air quality standards as the former always requires much greater setback distances than the latter.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental , Pradaria , Modelos Químicos , Odorantes/análise , Poluição do Ar/estatística & dados numéricos , Amônia/análise , Criação de Animais Domésticos , Animais , Poeira/análise , Sulfeto de Hidrogênio/análise , Aves Domésticas , Saskatchewan
9.
Sci Total Environ ; 690: 973-990, 2019 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-31302561

RESUMO

The paddy rice fields act as an important anthropogenic source of methane (CH4) to the atmosphere. The study of pattern, magnitude, and environmental controls of CH4 emissions are still insufficient due to limited measurements and understand of underlying drivers for variations of CH4 fluxes at different temporal scales. In this study, CH4 fluxes from a rice-wheat rotation agroecosystem in eastern China were continuously measured using the eddy covariance technique. The diurnal and seasonal variations of CH4 flux and potential controlling factors in 2016 were analyzed using wavelet coherence, conditional Granger causality, correlation analysis and path analysis methods. CH4 fluxes showed distinguishable diurnal variations with single peaks during 13: 00-16: 00 local time. At the diurnal timescale, gross primary productivity (GPP) regulates CH4 fluxes after accounting for the effects of latent heat flux (LE), air temperature (TA), and soil temperature (TS) on CH4 fluxes. LE mirrored the diurnal pattern of CH4 fluxes when the effects of TA and TS on CH4 fluxes were considered. Daily CH4 fluxes exhibited large seasonal variations, with the largest daily CH4 flux of 1191.78 mg C-CH4 m-2 d-1 on 29 July 2016. The daily CH4 fluxes were continuously low in the growing season of wheat, and sharply increased from very low values in late June to peaks in late July and early August, and then gradually decreased to low values at the end of the rice growing season in late November and early December. Correlation analysis and path analysis showed that seasonal variations of soil temperature, air temperature, and GPP had strong effects on daily CH4 fluxes during pre-panicle initiation of the rice growing season, while soil temperature and leaf area index (LAI) had very strong effects on daily CH4 fluxes during the post-panicle initiation stage. The total of CH4 fluxes from the rice-wheat rotation agroecosystem into the atmosphere amounted to 58.08 ±â€¯9.87 g C m-2 in 2016, and the annual net carbon (C) budget and greenhouse gas (GHG) budget were 163.50 ±â€¯9.87 g C m-2 and 2322.53 ±â€¯329.00 g CO2eq m-2, respectively. This study represents a comprehensive assessment of fluxes and drivers of CH4 from a rice-wheat rotation agroecosystem at different timescales. Additionally, the consecutive data of CH4 emission in this region will also useful for model calibration and validation.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental , Metano/análise , Agricultura , China , Gases de Efeito Estufa/análise , Oryza , Estações do Ano , Triticum
10.
Environ Monit Assess ; 191(8): 484, 2019 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-31280377

RESUMO

Epidemiological research requires accurate prediction of the concentrations of air pollutants. In this study, satellite-based estimates (OMI NO2), distance-weighted models (DWMs), and universal kriging (UK) are applied to land use regression (LUR) to predict annually and monthly averaged NO2 concentrations in the continental United States. In addition, to assess environmental risk, the relationship between NO2 concentrations and people potentially exposed to NO2 within urban areas is explored in 377 metropolitan statistical areas (MSAs). The results of this study show that the application of a combination of OMI NO2, UK, and DWMs to LUR yielded the highest cross-validated (CV) R2 values and the lowest root mean square error of prediction (RMSEP): 82.9% and 0.392 on a square root scale of ppb in the annual model and 70.4-83.5% and 0.408-0.518 on square root scale of ppb in the monthly models, respectively. Moreover, the model presented a spatially unbiased distribution of CV error terms. Models based on LUR provided more accurate NO2 predictions with lower RMSEP in urban areas than in rural areas. In addition, this study finds that the people living in the urban areas of MSAs, with larger populations and a higher percentage of children under 18 years of age, are likely to be exposed to higher NO2 concentrations. By contrast, people living in the urban areas of MSAs with a higher percentage of the elderly over 65 years of age are likely to be exposed to lower NO2 concentrations.


Assuntos
Poluição do Ar/estatística & dados numéricos , Exposição Ambiental/estatística & dados numéricos , Dióxido de Nitrogênio/análise , Adolescente , Idoso , Poluentes Atmosféricos/análise , Poluição do Ar/análise , Criança , Pré-Escolar , Monitoramento Ambiental/métodos , Humanos , Análise Espacial , Estados Unidos
11.
Sci Total Environ ; 691: 430-441, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31323588

RESUMO

Urine deposited by grazing animals is the main source of nitrous oxide (N2O) emissions in New Zealand. Recent studies have suggested that certain pasture plants, for example plantain (Plantago lanceolata), can curb N2O emissions from livestock systems. This study aimed to i) evaluate the potential of plantain for reducing N2O emissions from cattle urine patches; ii) determine the effect of including plantain in animal diets on urine-N loading and its influence on N2O emissions; and, iii) evaluate whether any effects on N2O emissions reduction could be attributed to a 'urine' or a 'plant' effect. A static chamber method was used to measure N2O fluxes from urine collected from cows fed a 0, 15, 30 or 45% plantain mixed with "standard" ryegrass/clover (Lolium perenne/Trifolium repens) diet and applied to plots with the corresponding percentage of plantain in the sward. In addition, we measured N2O emissions from different proportions of plantain in the sward (0, 30, 60 and 100%) that received urine collected from cows fed on ryegrass/clover. The urine N loading rates of animals fed plantain, significantly reduced with increasing proportions of plantain in the diet (r2 = 0.987, P < 0.01). There was a trend of lower N2O emissions with an increasing proportion of plantain in the diet (r2 = 0.830, P < 0.08). However, there was no significantly difference in the N2O emission factors (P > 0.10). Following applications of standard urine, total N2O emissions and emission factor reduced linearly as the proportion of plantain in the sward increased (r2 = 0.969, P < 0.05 and 0.974, P < 0.05, respectively). The results suggest that the efficacy of plantain as a N2O mitigation option is due to both a reduction in urinary N excretion and a plant effect. The latter could be due to biological nitrification inhibition (BNI) caused by the release of root exudates and/or changes in the soil microclimate.


Assuntos
Poluentes Atmosféricos/análise , Biodegradação Ambiental , Óxido Nitroso/análise , Agricultura/métodos , Animais , Bovinos , Dieta , Gado , Lolium , Nitrificação , Plantago , Verduras
12.
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
13.
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
14.
Sci Total Environ ; 691: 584-594, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31325858

RESUMO

Siloxanes are organo-silicon compounds containing Si-O-Si linkages and methyl branches. Depending on the structure, siloxanes can be divided into cyclic and linear compounds. Methyl siloxanes with small and medium molecular weights (molecular weights less than 500 g mol-1), are volatile under normal conditions, and hence are referred to as volatile methyl siloxanes (VMSs). VMSs are additive ingredients in many products such as plastics, rubber, personal care products, and household items. This review provides information on the distribution of VMSs in consumer products, indoor air and dust, and their implications for human exposure. VMSs have been used in personal care products and household items at concentrations on the order of hundreds to thousands of micrograms per gram which are the main sources of contamination in the indoor environments. VMSs have been found widely in indoor air and dust. A significant correlation existed between VMS concentrations in indoor air and dust. Among typical VMSs, dodecamethylcylcopentasiloxane (D5) is the major compound found in indoor environments. The human exposure doses to VMSs through dermal absorption, dust ingestion, and inhalation were compiled; Inhalation is a dominant pathway of exposure to VMSs, especially in indoor environments of occupational settings like hair salons. The human exposure doses were higher in children than in adults.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar em Ambientes Fechados/estatística & dados numéricos , Exposição Ambiental/estatística & dados numéricos , Monitoramento Ambiental , Siloxanas/análise , Humanos
15.
Sci Total Environ ; 691: 611-620, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31325861

RESUMO

The livestock sector is the main source of non-CO2 greenhouse gas (GHG) emissions in China. Decomposing the factors that influence non-CO2 GHG intensity in the livestock sector (LGI) serves as an important reference for the development of specific emission reduction policies. However, the difficulty lies in how to consider the relationship between emission reductions and the human food supply and economic development. In this study, a decomposition framework for the LGI in China was constructed from the concept of "environment-food-economy." The influencing factors that drove changes in LGI were interpreted at the environmental level, economic level, and scale level. Additionally, the logarithmic mean Divisia index (LMDI) method was used to quantify the contributions of these three drivers in 31 provinces across China from 1998 to 2016. The results showed that: (1) the LGI of China decreased by 80.02% during the study period. This decrease was mainly driven by the environmental and economic level factors of each province with a respective cumulative contribution of 51.96% and 34.10%. However, the scale-level factor of each province cumulatively suppressed the LGI drop by 6.04% in China. (2) For the contribution of the environmental-level factor, the top five provinces were Henan, Yunnan, Inner Mongolia, Guangxi, and Shandong. The top five provinces for the economic-level factor contribution were Henan, Sichuan, Shandong, Hebei, and Heilongjiang. (3) Under the concept of the livestock sector "environment-food-economy", improving the environmental and economic levels of the livestock sector in each province, and narrowing its inter-provincial gaps are two feasible ways that can be used to reduce China's LGI. Our research methodology is applicable to studies on the reduction of LGI in regions of different scales.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/estatística & dados numéricos , Criação de Animais Domésticos , Gases de Efeito Estufa/análise , Animais , China , Comércio , Desenvolvimento Econômico , Monitoramento Ambiental , Alimentos , Gado
16.
Sci Total Environ ; 691: 868-873, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31326810

RESUMO

BACKGROUND: The health effects of particulate matter (PM) air pollution on glucose metabolism have been rarely examined in children and adolescents. OBJECTIVE: We aimed to investigate the associations between long-term PM exposure and blood glucose and prevalence of impaired fasting glucose in a large population of Chinese children and adolescents. METHODS: In 2013, a total of 11,814 children and adolescents aged 7 to 18 years were recruited from seven provinces/municipalities in China. Fasting blood sample was taken for the measurement of blood glucose. Satellite-based spatial-temporal models were used to estimate exposure to ambient submicrometer particles (PM1), fine particles (PM2.5) and thoracic particles (PM10). Cross-sectional analyses were performed using mixed-effects multivariable linear and logistic regression models. RESULTS: After adjustment for a range of covariates, every 10 µg/m3 increment in PM1, PM2.5 and PM10 concentrations was associated with 0.160 [95% confidence interval (CI): 0.039, 0.280], 0.150 (95% CI: 0.044, 0.256) and 0.079 (95% CI: -0.009, 0.167) mmol/L higher blood glucose levels, respectively. PM exposure was also associated with higher prevalence of impaired fasting glucose, but the associations did not reach statistical significance [odds ratio per 10 µg/m3 increment in PM1, PM2.5 and PM10: 1.30 (95% CI: 0.86,1.96), 1.20 (95% CI: 0.85,1.69) and 1.08 (95% CI: 0.83,1.41)]. CONCLUSIONS: We found that long-term exposure to PM air pollution was associated with increased levels of blood glucose in children and adolescents. The associations were more evident for PM1 and PM2.5.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/estatística & dados numéricos , Glicemia/metabolismo , Exposição Ambiental/estatística & dados numéricos , Material Particulado/análise , Adolescente , Criança , China , Feminino , Humanos , Masculino
17.
Chemosphere ; 233: 786-795, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31340409

RESUMO

Microbial volatile organic compounds (mVCs) are formed in the metabolism of microorganisms and widely distributed in nature and pose threats to human health. However, the air pollution by microorganisms is a situation which is poorly understood. In this study, the cytotoxicity of E. aerogenes VCs was evaluated in the model organism Saccharomyces cerevisiae. E. aerogenes VCs inhibited the survival of yeast and triggered the formation of intracellular reactive oxygen species (ROS). The hypersensitive of MAP kinase mpk1/slt2 and 19S regulatory assembly chaperone adc17 mutants to the E. aerogenes VCs indicated cell wall integrity (CWI) pathway together with stress-inducible proteasome assembly regulation are essentially involved in mVCs tolerance mechanism. Furthermore, exposure to the mVCs resulted in the transcriptional upregulation of the CWI pathway, the regulatory particle assembly chaperones, and genes involved in proteasome regulations. Our research suggested that the ROS/MAPK signaling and proteasome regulatory pathway play pivotal roles in the integration and fine-tuning of the mVCs stress response. This study provides a molecular framework for future study of the effects of mVCs on more complex organisms, such as humans.


Assuntos
Enterobacter aerogenes/metabolismo , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/efeitos dos fármacos , Compostos Orgânicos Voláteis/farmacologia , Poluentes Atmosféricos/análise , Poluição do Ar/análise , Parede Celular/metabolismo , Citoplasma/metabolismo , Chaperonas Moleculares/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Ativação Transcricional
18.
Chemosphere ; 233: 852-861, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31340411

RESUMO

A common strategy to improve indoor air quality in households burning coal and biomass is the introduction of advanced combustion solid fuel stoves, which can use existing fuels yet emit fewer pollutants. Chemical composition of PM is affected by numerous combustion parameters, but is often not considered in energy transitions, despite varying toxicity among chemical components. We analyzed PM2.5 emissions from combustion of solid fuels (coal, wood, and straw; whole and pelletized) in a variety of stoves (cookstoves and heating stoves; traditional and semi-gasifier, including forced versus natural draft and fixed versus reciprocating grate). To assess the effects of fuel and stove type on PM2.5 composition, we measured elemental carbon (EC), organic carbon (OC), water-soluble OC, water-soluble inorganic ions (e.g. SO42-, Cl-, K+), and organic molecular markers. PM2.5 emissions from traditional stoves were mostly carbonaceous: 76-90% organic matter (OM), 5-6% EC, and less than 2% inorganic ions. In contrast, semi-gasifier stoves emitted more inorganic PM2.5: on average, ions comprised 65%, 9% was OM, and 4% was EC. Within the semi-gasifier cookstoves, forced-draft cookstove emissions had lower OM (1-3%) and higher ion concentrations (84-88%) than the natural-draft cookstove (5-14% OM, 30-83% ions). Levoglucosan was detected in PM2.5 from combustion of wood in the traditional cookstove and biomass pellets in the natural-draft semi-gasifier cookstove, but not from wood pellets in the forced-draft semi-gasifier cookstove. Across a range of different fuels and stoves, stove type influenced emitted PM composition more than fuel type, underscoring the impact of combustion conditions on PM chemical composition.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar em Ambientes Fechados/análise , Carbono/análise , Carvão Mineral/análise , Glucose/análogos & derivados , Material Particulado/análise , Biomassa , Culinária , Glucose/análise , Utensílios Domésticos , Produtos Domésticos , Madeira/química
19.
Chemosphere ; 233: 879-887, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31340414

RESUMO

Epidemiological studies have shown that fine particulate matter (PM2.5) has adverse impacts on human health. However, limited studies have investigated the effects of short-term exposure to PM2.5 and its constituents on mortality in China. This study used the generalized linear model (GLM) to investigate the effects of PM2.5 and its constituents, including organic carbon (OC), element carbon (EC), ammonium (NH4+), nitrate (NO3-), sulfate (SO42-), on different causes of mortality in Shanghai from January 1, 2013 to December 31, 2015. The single-day lagged model and the moving average lagged model were used to examine the lagging effects of pollutants on mortality. At lag0 day, PM2.5 had a significant effect on all-cause mortality, and a 10 µg/m3 increase leads to 0.68% increase in all-cause mortality (RR 1.0068, 95%CI 1.0013-1.0123). Among the five constituents, EC had the greatest impact on all-cause mortality in Shanghai, with 10.48% increase of mortality (RR 1.1048, 95%CI 1.0266-1.1891) per 10 µg/m3 increase of concentrations, followed by OC (RR 1.0577, 95%CI 1.0277-1.0886), NH4+ (RR 1.0272, 95%CI 1.0028-1.0522) and SO42- (RR 1.0104, 95%CI 1.0003-1.0206). For respiratory diseases mortality, EC, OC, NO3- and NH4+ had significant impacts and caused an increase of mortality by 44.99% (RR 1.4499, 95%CI 1.1813-1.7794), 10.40% (RR 1.1040, 95%CI 1.0260-1.1880), 5.338% (RR 1.0533, 95%CI 1.0097-1.0989) and 7.34% (RR 1.0734, 95%CI 1.0015-1.1505) per 10 µg/m3 increase of concentrations, respectively. The cumulative effect of PM2.5 on mortality was significant in Shanghai. Except for SO42-, the RR value of the single-day lagged model was smaller than the moving average lagged model.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/análise , Exposição Ambiental/efeitos adversos , Pneumopatias/induzido quimicamente , Pneumopatias/mortalidade , Material Particulado/análise , Compostos de Amônio/análise , Carbono/análise , China , Humanos , Modelos Lineares , Nitratos/análise , Sulfatos/análise
20.
Chemosphere ; 233: 966-974, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31340424

RESUMO

The lower stretch of the perennial transboundary river Ganga is known as the Hooghly River (HR) in India. Despite the strict ban, HR has been evidenced with residues of pesticidal persistent organic pollutants (POPs) from primary and secondary sources. Hence surface water sampling and passive air sampling (PAS) were conducted along the urban and suburban transects and discharge points to study the fate of pesticidal (POPs along the HR. Excluding the discharge points, the mean concentration of hexachlorocyclohexane (HCH), dichlorodiphenyltrichloroethane (DDT) and endosulfan (ENDO) were 6 ng/L, 4 ng/L and 36 ng/L in surface water and 888 pg/m3, 1689 pg/m3 and 429 pg/m3 in atmosphere respectively. Percentage composition and diagnostic ratios strongly suggest ongoing use of technical HCH, DDT and endosulfan. Elevated endosulfan in surface water has been related to its usage during fishing. Except for p,p'-DDE, α-Endo and ß-Endo, fluxes at the air-water interface showed net deposition from air to water for all the OCPs in urban and suburban transects. The estimated eco-toxicological risk assessment showed risk on lower trophic organisms due to DDT and lindane mostly at the discharge points. Endosulfan can pose potential risk to the edible fishe species in the HR.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental , Praguicidas/análise , Rios/química , Poluentes Químicos da Água/análise , Atmosfera/química , DDT/análise , Diclorodifenil Dicloroetileno/análise , Endossulfano/análise , Hexaclorocicloexano/análise , Índia , Água/química
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