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1.
Environ Monit Assess ; 193(6): 330, 2021 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-33963453

RESUMEN

In this paper, the gas pollutants in motor vehicle exhaust are taken as the research object. The diagnostic index system of motor vehicle gas pollutants on environmental pollution is constructed, based on the environmental pollution caused by motor vehicle exhaust. The emission intensity of various types of vehicles was studied. The least-square method is used to construct the diagnostic functions of different types of vehicle gas pollutants; the vehicle emission factors of different types of motor vehicle gas pollutants are obtained. By exploring the spatial-temporal correlation of vehicle emissions under traffic conditions, uncertainty mathematical theory is used to establish a spatial-temporal diagnosis model of vehicle gas pollutants on environmental pollution, and multiple correlation coefficients are used to conduct accuracy test. The research results can not only determine the pollution problem of motor vehicle emissions to the environment but also effectively evaluate the emission level of gas pollutants in the exhaust gas of motor vehicles. The application results show that the spatial-temporal diagnostic model of vehicle gas pollutants for environmental pollution has better guiding significance and practical value in solving environmental pollution problems.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire , Contaminantes Ambientales , Contaminantes Atmosféricos/análisis , Contaminación del Aire/análisis , Monitoreo del Ambiente , Vehículos a Motor , Emisiones de Vehículos/análisis
2.
Environ Monit Assess ; 193(6): 331, 2021 May 08.
Artículo en Inglés | MEDLINE | ID: mdl-33966107

RESUMEN

This study investigates the changes of short-lived climate pollutants and other air pollutants during the COVID-19 pandemic in Tehran, Iran. Concentrations of air pollutants were obtained from 21 monitoring stations for the period from 5 January 2019 to 5 August 2019, representing normal conditions unaffected by COVID-19, and the period 5 January 2020 to 5 August 2020, i.e., during the COVID-19 crisis. We concentrated our analysis on three time windows (23 February 2020 to 15 March 2020, 18 March 2020 to 3 April 2020, and 5 April 2020 to 17 April 2020) during the lockdown when different sets of measures were taken to limit the spread of COVID-19. In comparison to the period not affected by COVID-19 measures, mean concentrations of pollutants were increased during the first lockdown period; when the number of COVID-19 patients increased sharply compared to the other periods, the mean surface concentrations of NO2, SO2, and CO were decreased and concentrations of other pollutants (i.e., O3, PM10, and PM2.5) were increased during the second lockdown period compared to the corresponding period in 2019. In the third period, the mean concentrations were decreased compared to the corresponding period in 2019. For the full period, decreases in mean concentrations of O3, NO2, SO2, CO, and PM10 and increases in PM2.5 were observed during the COVID-19 crisis, compared to 2019. Overall, the strongest reductions, 12% and 6%, respectively, were observed for CO and NO2, pointing to reduced emissions from traffic as a result of lockdown measures. The concentrations of other pollutants changed little, suggesting that the lockdown measures did not result in strong changes in the emissions from stationary sources.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire , Contaminantes Ambientales , Contaminantes Atmosféricos/análisis , Contaminación del Aire/análisis , Control de Enfermedades Transmisibles , Monitoreo del Ambiente , Humanos , Irán/epidemiología , Pandemias , Material Particulado/análisis
3.
Sci Total Environ ; 773: 145709, 2021 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-33940766

RESUMEN

BACKGROUND: Heightening oxidative stress and inflammation is an important pathophysiological mechanism underlying air pollution health effects in people with asthma. Melatonin can suppress oxidative stress and inflammation in pulmonary and circulatory systems. However, the role of melatonin in the oxidative stress and physiological responses to air pollution exposure has not been examined in children with asthma. METHODS: In this panel study of 43 asthmatic children (5-13 years old), each child had 4 clinic visits with a 2-week interval between two consecutive visits. At each visit, urine samples were collected and subsequently analyzed for 6-sulfatoxymelatonin (aMT6s) as a surrogate of circulating melatonin and for malondialdehyde (MDA) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) as two biomarkers of systemic oxidative stress. At each clinic visit, children were measured for pulmonary function and fractional exhaled nitric oxide (FeNO, a marker of pulmonary inflammation). None of the children reported to have taking melatonin supplementation. Concentrations of indoor and ambient PM2.5 and ozone (O3) were combined with individual time-activity data to calculate personal air pollutant exposures. RESULTS: We found that interquartile range increases in urinary MDA and 8-OHdG concentrations were associated with significantly increased urinary aMT6s concentrations by 73.4% (95% CI: 52.6% to 97.0%) and 41.7% (22.8% to 63.4%), respectively. Increases in daily personal exposure to O3 and to PM2.5 were each associated with increased urinary aMT6s concentrations. Increasing urinary aMT6s concentrations were associated with decreased FeNO and resonant frequency, indicating improved airway inflammation and lung elasticity, respectively. CONCLUSION: The results suggest that systemic oxidative stress heightened by air pollution exposure may stimulate melatonin excretion as a defense mechanism to alleviate the adverse effects.


Asunto(s)
Contaminantes Atmosféricos , Asma , Melatonina , Adolescente , Contaminantes Atmosféricos/efectos adversos , Contaminantes Atmosféricos/análisis , Niño , Preescolar , Humanos , Estrés Oxidativo , Material Particulado/efectos adversos , Material Particulado/análisis
4.
J Environ Manage ; 289: 112431, 2021 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-33819655

RESUMEN

The aim of this work is to evaluate the atmospheric rainwater chemistry and neutralization potential in oil producing areas of southern region of Nigeria. Rainwater samples were analysed for pH, EC, Cl-, SO42+, NO3-, Ca2+, and NH4+. Correlation, principal component analysis (PCA) and neutralization indicators as source apportionment methods were used to determine atmospheric acid precursors . Results show that the collected samples were severely acidified with pH value of 5.5 in oil producing communities and weak acid: pH 6.5 in non oil producing areas and varied with seasons. Fractional acidity (FA) constituted 98-99% of neutralizing ability, neutralization factor (NF) recorded Cl-, Ca2+ and NH4+ in values of 0.41, 0.43 and 0.003 with Ca2+ from sea salt, being the most neutralizing substance than NH4+from agricultural practice. The neutralizing and acidifying potentials (NP/AP) recorded a mean of 0.4, showing weak alkaline effect on atmospheric acid rain in oil producing communities. The positive correlation among ionic species implicates pH, SO42+and NO3 as causes of severe atmospheric acidity. Conclusions were made that enforcement of the existing environmental laws to checkmate the emission of acid precursors is crucial for the survival of man and entire ecosystem.


Asunto(s)
Lluvia Ácida , Contaminantes Atmosféricos , Lluvia Ácida/análisis , Contaminantes Atmosféricos/análisis , Ecosistema , Monitoreo del Ambiente , Humanos , Nigeria , Estaciones del Año
6.
J Environ Manage ; 289: 112510, 2021 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-33827002

RESUMEN

Air quality (AQ) is a global concern for human health management. Therefore, air quality monitoring (AQM) and its management is a must-needed activity for the current world environment. A systematic review of various sensors and systems for AQ management may strengthen our understanding of the monitoring and management of AQ. Thus, the current review presents details on sensors/systems available for AQ assessment, monitoring, and management. First, we had gone through the published literature based on special keywords including AQM, Particulate Matter (PM), Carbon Mono-oxide (CO), Sulfur di-Oxide (SO2), and Nitrogen di-Oxide (NO2) among others, and identified the current scenario of research in AQ management. We discussed various sensors/systems available for the AQ management based on self-conceptualised five major categories including, ground-based AQS (wet chemistry) systems, ground-based digital sensors systems, aerial sensors systems, satellite-based sensors systems, and integrated systems. The prospects in the field of AQ assessment and management (AQA&M) were then discussed in detail. We concluded that the AQA&M can be better achieved by coupling new technologies like ground-based smart sensors, satellite remote sensing sensors, Geospatial technologies, and computational technologies like machine learning, Artificial intelligence, and Internet of Things (IoT). The current work may lead to a junction of information for connecting these sensors/systems, which is expected to be beneficial in future AQ research and management.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire , Contaminantes Atmosféricos/análisis , Contaminación del Aire/análisis , Inteligencia Artificial , Monitoreo del Ambiente , Humanos , Material Particulado/análisis
7.
J Environ Manage ; 289: 112535, 2021 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-33895580

RESUMEN

In comparison with various restaurant cuisines, common cooking methods are more represented in residential cooking. Rather than the exhaust pipe or the ambient environment in the cooking room, the respiration zone better reflects the health risks for operators. In this study, the concentrations of total volatile organic compound (TVOC) released from six typical cooking methods were monitored online in the respiratory zone, and the VOCs were analysed by GC-MS. The results demonstrated that the intensities of exposure to TVOC for the different cooking methods decreased as follows: stir-frying (3.809 mg/m3) > quick-frying (2.724 mg/m3) > deep-frying (2.465 mg/m3) > boiling (1.161 mg/m3)≈stewing (1.149 mg/m3) > limit in China (0.600 mg/m3) > steaming (0.440 mg/m3). The intense ventilation mode of the ventilator reduced exposure to TVOC by 45-63% relative to the medium mode. Eleven types of VOCs (approximately 200 compounds) were found in Chinese residential cooking fumes, and the predominant contaminants were aldehydes, followed by alkanes, unsaturated aldehydes, alcohols and alkenes. The mass percentage of aromatic hydrocarbons in all VOCs emitted from Chinese residential cooking was only 1%, while the value was 17-48% for commercial restaurants. The results of a health risk assessment revealed that the total potential carcinogenic risk level for VOCs released by six residential cooking methods decreased as follows: deep-frying (5.75) > stir-frying (3.95) > quick-frying (2.94) > stewing (1.99) > boiling (1.73) > steaming (1.48). Chinese residential cooking, and especially deep frying, has potential health impacts for the operator.


Asunto(s)
Contaminantes Atmosféricos , Contaminantes Atmosféricos/análisis , China , Culinaria , Monitoreo del Ambiente , Medición de Riesgo
8.
Environ Sci Technol ; 55(9): 5689-5700, 2021 05 04.
Artículo en Inglés | MEDLINE | ID: mdl-33797233

RESUMEN

Residential solid fuel combustion (RSFC) is a key cause of air pollution in China. In these serial studies, field measurements of RSFC from 166 rural households in eastern China were conducted to update the database of emission factors (EFs) and chemical profiles of gaseous and particulate organic pollutants, and the present study focuses on the intermediate volatile organic compounds (IVOCs), which are precursors of secondary organic aerosol (SOA). The results show that the averaged EFs of IVOCs (EFIVOC) for crop straw, fuelwood, and coal are 550.7 ± 397.9, 416.1 ± 249.5, and 361.9 ± 308.0 mg/kg, respectively, which are among the EFIVOC of gasoline vehicle, diesel vehicle, non-road machinery, and heavy fuel oil vessel, and are significantly affected by fuel, stove, and combustion efficiency. The percentages of normal alkanes (n-alkanes), branched alkanes (b-alkanes), polycyclic aromatic hydrocarbons (PAHs), and unresolved complex mixture from RSFC are 3.5 ± 1.6, 8.0 ± 3.7, 17.6 ± 6.7, and 70.9 ± 8.1%, respectively, and the compositions are featured by lower b-alkanes and higher PAHs than those of vehicle sources. The proportions of some individual n-alkanes and PAHs (such as n-C12-n-C15, naphthalene, and its alkyl substituents) can be used as indicators to differentiate RSFC from vehicle sources, while methoxyphenols can be used to distinguish biomass burning from coal combustion. Based on China's energy statistics, the total IVOC emissions from RSFC in 2014 were 175.9 Gg. These data will help to update the IVOC emission inventory and improve the estimates of SOA production in China.


Asunto(s)
Contaminantes Atmosféricos , Hidrocarburos Policíclicos Aromáticos , Compuestos Orgánicos Volátiles , Aerosoles/análisis , Contaminantes Atmosféricos/análisis , China , Material Particulado/análisis , Hidrocarburos Policíclicos Aromáticos/análisis , Emisiones de Vehículos/análisis , Compuestos Orgánicos Volátiles/análisis
9.
Environ Sci Technol ; 55(9): 5763-5771, 2021 05 04.
Artículo en Inglés | MEDLINE | ID: mdl-33818073

RESUMEN

Coal and coal gangue spontaneous combustion (CGSC) occurs globally, causing significant environmental pollution. However, its emissions are poorly quantified and are overlooked in global or regional air pollutant emission inventories in previous studies, resulting in the underestimation of its impacts on climate, environment, and public health. This study quantified the emissions of various air pollutants originating from CGSC in Wuhai, a city in China, investigated emission characteristics, and estimated the contribution of CGSC emissions to fine particulate matter (PM2.5) air pollution and related health impacts on a regional scale. The results revealed that the CGSC-related PM2.5 emissions were approximately 4643 t a-1 (95% confidence interval (95% CI): 721; 10447), accounting for 26.3% of the total PM2.5 emissions. Alkanes, alkenes, and aromatics accounted for 69.4, 17.9, and 2.9%, respectively, of the total emissions of volatile organic compounds (VOCs). Due to CGSC emissions, the ambient PM2.5 concentration in Wuhai increased by 5.7 µg m-3 on average, while the nitrate concentration decreased. The number of premature deaths caused by exposure to ambient PM2.5 associated with CGSC reached 381 (95% CI: 290; 452) in Wuhai and surrounding cities in 2017. Urgent control strategies and engineering techniques are needed to mitigate CGSC to protect public health.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire , Contaminantes Atmosféricos/análisis , Contaminación del Aire/análisis , China , Ciudades , Carbón Mineral/análisis , Monitoreo del Ambiente , Material Particulado/análisis , Combustión Espontánea
10.
Environ Sci Technol ; 55(9): 5636-5647, 2021 05 04.
Artículo en Inglés | MEDLINE | ID: mdl-33822602

RESUMEN

Evidence of the effects of various particle sizes and constituents on blood biomarkers is limited. We performed a panel study with five repeated measurements in 88 healthy college students in Guangzhou, China between December 2017 and January 2018. Mass concentrations of particles with aerodynamic diameters ≤ 2.5 µm (PM2.5), PM1, and PM0.5 and number concentrations of particles with aerodynamic diameters ≤ 200 nm (PN0.2) and PN0.1 were measured. We used linear mixed-effect models to explore the associations of size-fractionated particulate matter and PM2.5 constituents with five blood biomarkers 0-5 days prior to blood collection. We found that an interquartile range (45.9 µg/m3) increase in PM2.5 concentration was significantly associated with increments of 16.6, 3.4, 12.3, and 8.8% in C-reactive protein (CRP), monocyte chemoattractant protein-1 (MCP-1), soluble vascular cell adhesion molecule-1 (sVCAM-1), and endothelin-1(ET-1) at a 5-day lag, respectively. Similar estimates were observed for PM1, PM0.5, PN0.2, and PN0.1. For PM2.5 constituents, consistent positive associations were observed between F- and sVCAM-1 and CRP and between NH4+ and MCP-1, and negative associations were found between Na+ and MCP-1 and ET-1, between Cl- and MCP-1, and between Mg2+ and sVCAM-1. Our results suggested that both particle size and constituent exposure are significantly associated with circulating biomarkers among healthy Chinese adults. Particularly, PN0.1 at a 5-day lag and F- and NH4+ are the most associated with these blood biomarkers.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire , Contaminantes Atmosféricos/análisis , Biomarcadores , China , Exposición a Riesgos Ambientales/análisis , Humanos , Tamaño de la Partícula , Material Particulado/análisis , Adulto Joven
11.
Environ Sci Technol ; 55(9): 6160-6170, 2021 05 04.
Artículo en Inglés | MEDLINE | ID: mdl-33825441

RESUMEN

Vaporizable cannabis concentrates (VCCs) consumed as a liquid (vaping) or a waxy solid (dabbing) are becoming increasingly popular. However, their associated emissions and impacts have not been fully described. Mixtures containing different proportions of 12 VCC terpenoids and high MW compounds were heated at 100-500 °C inside a room-sized chamber to simulate emissions. Terpenoids, thermal degradation byproducts, and ultrafine particles (UFPs) were quantified in the chamber air. Air samples contained over 50% of emitted monoterpenes and less than 40% of released sesquiterpenes and terpene alcohols. Eleven degradation byproducts were quantified, including acrolein (1.3-3.9 µg m-3) and methacrolein (2.0 µg m-3). A large amount of UFPs were released upon heating and remained airborne for at least 3 h. The mode diameter increased from 80 nm at 100 °C to 140 nm at 500 °C, and particles smaller than 250 nm contributed to 90% of PM1.0. The presence of 0.5% of lignin, flavonoid, and triterpene additives in the heated mixtures resulted in a threefold increase in the particle formation rate and PM1.0 concentration, suggesting that these high-molecular-weight compounds enhanced aerosol inception and growth. Predicted UFP emission rates in typical consumption scenarios (6 × 1011-2 × 1013 # min-1) were higher than, or comparable with, other common indoor sources such as smoking and cooking.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire Interior , Cannabis , Aerosoles , Contaminantes Atmosféricos/análisis , Contaminación del Aire Interior/análisis , Culinaria , Monitoreo del Ambiente , Tamaño de la Partícula , Material Particulado/análisis , Terpenos
12.
Environ Sci Technol ; 55(9): 5701-5710, 2021 05 04.
Artículo en Inglés | MEDLINE | ID: mdl-33826309

RESUMEN

Smog chamber experiments were conducted to characterize the light absorption of brown carbon (BrC) from primary and photochemically aged coal combustion emissions. Light absorption was measured by the UV-visible spectrophotometric analysis of water and methanol extracts of filter samples. The single-scattering albedo at 450 nm was 0.73 ± 0.10 for primary emissions and 0.75 ± 0.13 for aged emissions. The light absorption coefficient at 365 nm of methanol extracts was higher than that of water extracts by a factor of 10 for primary emissions and a factor of 7 for aged emissions. This suggests that the majority of BrC is water-insoluble even after aging. The mass absorption efficiency of this BrC (MAE365) for primary OA (POA) was dependent on combustion conditions, with an average of 0.84 ± 0.54 m2 g-1, which was significantly higher than that for aged OA (0.24 ± 0.18 m2 g-1). Secondary OA (SOA) dominated aged OA and the decreased MAE365 after aging indicates that SOA is less light absorbing than POA and/or that BrC is bleached (oxidized) with aging. The estimated MAE365 of SOA (0.14 ± 0.08 m2 g-1) was much lower than that of POA. A comparison of MAE365 of residential coal combustion with other anthropogenic sources suggests that residential coal combustion emissions are among the strongest absorbing BrC organics.


Asunto(s)
Contaminantes Atmosféricos , Carbono , Aerosoles/análisis , Contaminantes Atmosféricos/análisis , Carbono/análisis , Carbón Mineral , Material Particulado/análisis , Agua
13.
Environ Sci Technol ; 55(9): 5668-5676, 2021 05 04.
Artículo en Inglés | MEDLINE | ID: mdl-33851834

RESUMEN

The community multiscale air quality (CMAQ) model was modified to track the evolution of the atmospheric age (τ) distribution of primary particulate matter (PPM) and secondary inorganic aerosol components (nitrate, sulfate, and ammonium ion, NSA). The modified CMAQ gas and aerosol mechanisms represent the same species emitted at different times as an age-resolved mixture, using multiple age-tagged variables and a dynamic age-bin advancing scheme. The model was applied to study the spatial and temporal evolution of τ for PPM and NSA in January 2013 to understand the formation and regional transport of PM and the precursor gases during severe winter pollution episodes in China. The results showed that increases in PPM and NSA concentrations during high pollution periods in polluted urban areas were typically associated with increases in the mean atmospheric age (τ̅) due to the accumulation of local emissions and regional transport of aged pollutants. Some of the rapid sulfate growth events at the beginning of multiday air pollution episodes were driven by regional transport of aged particles. In heavily polluted cities, while most of the monthly average PPM had τ less than 10 h, more than half of the sulfate had τ greater than 20-30 h. Regional distributions showed that very aged sulfate particles with τ > 96 h accounted for a significant portion of the total sulfate and had a very broad spatial distribution. However, aged ammonium ions had very low concentrations. Aged nitrate also had lower concentrations and more limited spatial distributions than sulfate due to differences in the atmospheric lifetime between SO2 and NOx. The estimated NOx lifetime of approximately ∼24 h in China agrees with a satellite-based estimation of 21 h. Potential applications of the age distribution analysis include evaluating the impacts of meteorology on air quality and developing short-term emission control strategies.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire , Aerosoles/análisis , Distribución por Edad , Contaminantes Atmosféricos/análisis , Contaminación del Aire/análisis , Atmósfera , China , Ciudades , Monitoreo del Ambiente , Material Particulado/análisis , Estaciones del Año
14.
Environ Sci Technol ; 55(9): 6449-6458, 2021 05 04.
Artículo en Inglés | MEDLINE | ID: mdl-33856785

RESUMEN

Clarifying the sources and fates of atmospheric mercury (Hg) in the Antarctic is crucial to understand the global Hg circulation and its impacts on the fragile ecosystem of the Antarctic. Herein, the annual variations in the isotopic compositions of total gaseous Hg (TGM), with 5-22 days of sampling duration for each sample, were presented for the first time to provide isotopic evidence of the sources and environmental processes of gaseous Hg around the Chinese Great Wall Station (GWS) in the western Antarctic. Different from the Arctic tundra and lower latitude areas in the northern hemisphere, positive δ202Hg (0.58 ± 0.21‰, mean ± 1SD) and negative Δ199Hg (-0.30 ± 0.10‰, mean ± 1SD) in TGM at the GWS indicated little impact from the vegetation-air exchange in the Antarctic. Correlations among TGM Δ199Hg, air temperature, and ozone concentrations suggested that enhanced katabatic wind that transported inland air masses to the continental margin elevated TGM Δ199Hg in the austral winter, while the surrounding marine surface emissions controlled by sea-ice dynamics lowered TGM Δ199Hg in the austral summer. The oxidation of Hg(0) might elevate Δ199Hg in TGM during atmospheric Hg depletion events but have little impact on the seasonal variations of atmospheric Hg isotopes. The presented atmospheric Hg isotopes were essential to identify the transport and transformation of atmospheric Hg and further understand Hg cycling in the Antarctic.


Asunto(s)
Contaminantes Atmosféricos , Mercurio , Contaminantes Atmosféricos/análisis , Regiones Antárticas , Ecosistema , Monitoreo del Ambiente , Mercurio/análisis , Viento
15.
Environ Sci Technol ; 55(9): 5742-5751, 2021 05 04.
Artículo en Inglés | MEDLINE | ID: mdl-33861084

RESUMEN

As stricter regulations continue to reduce vehicular emissions, other emission sources such as evaporative emissions from road building and volatile consumer products have become more important in overall pollutant forming emissions in many urban areas. Emission regulations have historically targeted volatile organic compounds (VOCs) to reduce ozone, but intermediate volatility organic compounds (IVOCs) also contribute to ozone formation and the formation of secondary organic aerosol (SOA) that often dominates fine particulate matter. Emission rates and pollutant formation from IVOCs are not well constrained in current inventories and models. This study uses diesel fuel as a representative IVOC mixture in evaporation tests performed in a wind tunnel under varying wind speeds and liquid diesel temperatures. Comprehensive composition measurements guided the development of a model to determine rates of evaporation and estimate pollutant production. Results show that reducing IVOC emissions can result in significant reductions in ozone formation, in addition to the expected reductions in SOA formation, and that IVOC emissions can continue over the course of a month. Ozone formation from IVOC emissions is equal to that from VOCs after 3 days of evaporation at 0.65 g-ozone/g-diesel released. SOA formation is dominated by IVOCs, reaching 0.2 g-SOA/g-diesel released after 30 days.


Asunto(s)
Contaminantes Atmosféricos , Contaminantes Ambientales , Ozono , Compuestos Orgánicos Volátiles , Aerosoles/análisis , Contaminantes Atmosféricos/análisis , Emisiones de Vehículos/análisis , Compuestos Orgánicos Volátiles/análisis , Volatilización
16.
Environ Sci Technol ; 55(9): 6116-6127, 2021 05 04.
Artículo en Inglés | MEDLINE | ID: mdl-33870687

RESUMEN

Several recent studies in China have associated raised mortality risks with chronic exposure to ambient PM2.5. However, cohort evidence covering general populations and more homogeneous regions is extensively scarce. We conceived a nationwide perspective cohort study from 2010 through 2018, by enrolling 30 946 adult men and women aged 16-110 years from 25 provincial regions in mainland China. Cox proportional hazards models with time-varying exposures were adopted to quantify longitudinal association of PM2.5 exposure with all-cause mortality. A total of 1762 death events occurred during a median follow-up of 8.1 years. Participants were exposed to a broad range of annual mean PM2.5 concentrations (2.4-112 µg/m3), with an average estimate of 47.5 µg/m3. A 10-µg/m3 increase in annual average of PM2.5 exposure was associated with an hazard ratio of 1.055 (95% confidence interval: 1.022-1.088, p < 0.001) for all-cause mortality. We estimated totally 2.68 million deaths attributable to ambient PM2.5 in 2015, yielding a remarkable reduction of 36.7 thousand compared to the estimate in 2010 (2.72 million deaths). This study added nationally representative evidence regarding concentration-response function for long-term PM2.5-mortality association in Chinese adults, which may significantly contribute to national and global assessments of PM2.5-attributable death burden.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Contaminantes Atmosféricos/efectos adversos , Contaminantes Atmosféricos/análisis , Contaminación del Aire/análisis , China/epidemiología , Estudios de Cohortes , Exposición a Riesgos Ambientales/efectos adversos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Mortalidad , Material Particulado/efectos adversos , Material Particulado/análisis , Adulto Joven
17.
Environ Sci Technol ; 55(9): 5648-5656, 2021 05 04.
Artículo en Inglés | MEDLINE | ID: mdl-33871991

RESUMEN

Although evidences showed an overall reduction in outdoor air pollution levels across the globe due to COVID-19-related lockdown, no comprehensive assessment was available for indoor air quality during the period of stay-at-home orders, despite that the residential indoor environment contributes most to personal exposures. We examined temporal and diurnal variations of indoor PM2.5 based on real-time measurements from 139 indoor-outdoor co-located low-cost PurpleAir sensor sets across California for pre-, during, and post-lockdown periods in 2020 and "business-as-usual" periods in 2019. A two-step method was implemented to systematically control the quality of raw sensor data and calibrate the sensor data against co-located reference instruments. During the lockdown period, 17-24% higher indoor PM2.5 concentrations were observed in comparison to those in the 2019 business-as-usual period. In residential sites, a clear peak in PM2.5 concentrations in the afternoon and elevated evening levels toping at roughly 10 µg·m-3 was observed, which reflects enhanced human activity during lunch and dinner time (i.e., cooking) and possibly more cleaning and indoor movement that increase particle generation and resuspension in homes. The contribution of indoor-generated PM2.5 to total indoor concentrations increased as high as 80% during and post-lockdown periods compared to before lockdown.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire Interior , Contaminantes Atmosféricos/análisis , Contaminación del Aire Interior/análisis , California , Control de Enfermedades Transmisibles , Monitoreo del Ambiente , Humanos , Tamaño de la Partícula , Material Particulado/análisis
18.
Environ Sci Technol ; 55(9): 5677-5688, 2021 05 04.
Artículo en Inglés | MEDLINE | ID: mdl-33874721

RESUMEN

Emissions of light-absorbing black carbon (BC) and organic aerosol (OA) from biomass burning are presented as complex mixtures, which introduce challenges in modeling their absorbing properties. In this study, we chose typical residential wood burning emission and used a novel designed chamber to investigate the early stage evolution of plumes from different burning phases under real ambient conditions. The detailed mixing state between BC and OA was evaluated, on the basis of which optical modeling was performed to achieve a closure of aerosol-absorbing properties. Intensive secondary OA (SOA) formation was observed under solar radiation. OA from flaming conditions showed a higher absorptivity than from smoldering conditions, as OA is mostly internally and externally mixed with BC, respectively. For flaming (smoldering), the imaginary refractive index of OA (kOA) was initially at 0.03 ± 0.01 (0.001) and 0.15 ± 0.02 (0.05 ± 0.02) at λ = 781 and 405 nm, respectively, with a half-decay time of 2-3 h in light but a <40% decrease under dark within 5 h. The production of less-absorbing SOA in the first 1-2 h and possible subsequent photobleaching of chromophores contributed to the decrease of kOA. The enhanced abundance but decreased absorptivity of coatings on BC resulted in a relatively maintainable absorptivity of BC-containing particles during evolution.


Asunto(s)
Contaminantes Atmosféricos , Madera , Aerosoles/análisis , Contaminantes Atmosféricos/análisis , Atmósfera , Biomasa , Carbono , Humo , Hollín/análisis , Madera/química
19.
Environ Sci Technol ; 55(9): 6107-6115, 2021 05 04.
Artículo en Inglés | MEDLINE | ID: mdl-33878861

RESUMEN

Using hourly measures across a full year of crowd-sourced data from over 1000 indoor and outdoor pollution monitors in the state of California, we explore the temporal and spatial relationship between outdoor and indoor particulate matter (PM) concentrations for different particle sizes. The scale of this study offers new insight into both average penetration rates and drivers of heterogeneity in the outdoor-indoor relationship. We find that an increase in the daily outdoor PM concentration of 10% leads to an average increase of 4.2-6.1% in indoor concentrations. The penetration of outdoor particles to the indoor environment occurs rapidly and almost entirely within 5 h. We also provide evidence showing that penetration rates are associated with building age and climatic conditions in the vicinity of the monitor. Since people spend a substantial amount of each day indoors, our findings fill a critical knowledge gap and have significant implications for government policies to improve public health through reductions in exposure to ambient air pollution.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire Interior , Colaboración de las Masas , Contaminantes Atmosféricos/análisis , Contaminación del Aire Interior/análisis , Monitoreo del Ambiente , Humanos , Tamaño de la Partícula , Material Particulado/análisis
20.
Environ Sci Technol ; 55(9): 5657-5667, 2021 05 04.
Artículo en Inglés | MEDLINE | ID: mdl-33881834

RESUMEN

A new airborne system, the Whole Air Sampling Pilotless Platform (WASPP), is described for the collection of whole air samples and in situ meteorological measurements onboard a commercial hexacopter. Rapid sample collection enables the collection ≤15 air samples per flight in positively pressurized miniature canisters, subsequently analyzed on a mated analytical system for up to 80 nonmethane volatile organic compounds (VOCs). The WASPP is well suited to investigate VOC gradients in urban environments impacted by traffic, industry, and oil and natural gas (O&NG) development, but has the sensitivity to characterize continental background conditions, as shown here using a subset of >40 species. We document empirical tests to minimize the influence of rotor wash and other sampling artifacts and report favorable results of laboratory-based calibrations of the WASPP's meteorological sensors and field-based comparisons of WASPP's VOC measurements and horizontal wind velocity measurements. Airborne WASPP measurements can complement and enhance ground-based VOC monitoring efforts by providing substantial meteorological and VOC measurement capability across vertical and horizontal spatial scales. These measurements reveal strong vertical gradients in VOC mixing ratios, depending on local meteorology and sources. WASPP has wide applicability for pollution source identification and quantification of hazardous air pollutants and precursors of criteria pollutants, including monitoring O&NG emissions or industry fenceline monitoring.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire , Compuestos Orgánicos Volátiles , Contaminantes Atmosféricos/análisis , Contaminación del Aire/análisis , Aeronaves , Monitoreo del Ambiente , Compuestos Orgánicos Volátiles/análisis
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