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1.
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
2.
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
3.
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
4.
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
5.
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
6.
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
7.
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
8.
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
9.
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
10.
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
11.
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
12.
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
13.
Environ Sci Technol ; 55(9): 5752-5762, 2021 05 04.
Artículo en Inglés | MEDLINE | ID: mdl-33890767

RESUMEN

Effective mitigation of surface ozone pollution entails detailed knowledge of the contributing precursors' sources. We use the GEOS-Chem adjoint model to analyze the precursors contributing to surface ozone in the Beijing-Tianjin-Hebei area (BTH) of China on days of different ozone pollution severities in June 2019. We find that BTH ozone on heavily polluted days is sensitive to local emissions, as well as to precursors emitted from the provinces south of BTH (Shandong, Henan, and Jiangsu, collectively the SHJ area). Heavy ozone pollution in BTH can be mitigated effectively by reducing NOx (from industrial processes and transportation), ≥C3 alkenes (from on-road gasoline vehicles and industrial processes), and xylenes (from paint use) emitted from both BTH and SHJ, as well as by reducing CO (from industrial processes, transportation, and power generation) and ≥C4 alkanes (from industrial processes, paint and solvent use, and on-road gasoline vehicles) emissions from SHJ. In addition, reduction of NOx, xylene, and ≥C3 alkene emissions within BTH would effectively decrease the number of BTH ozone-exceedance days. Our analysis pinpoint the key areas and activities for locally and regionally coordinated emission control efforts to improve surface ozone air quality in BTH.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire , Ozono , Contaminantes Atmosféricos/análisis , Contaminación del Aire/análisis , Beijing , China , Monitoreo del Ambiente , Material Particulado/análisis
14.
Water Sci Technol ; 83(8): 2012-2024, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33905369

RESUMEN

The distribution and ecological risks of 11 phenolic compounds were studied in Weihe River, Northwest China. The concentrations of phenolic compounds were determined by ultra-high performance liquid chromatography (UPLC). The total concentration of 11 phenolic compounds (∑PC11) ranged from 0.06 to 14.12 µg/L with an average of 5.22 µg/L in water, from 0.92 to 34,885 µg/g with an average of 4,446 µg/g in suspended particulate matter (SPM), and from 3.54 to 34.09 µg/g with an average of 11.09 µg/g in sediment. For individual phenolic compound, the mean concentration of pentachlorophenol was the highest in water (2.65 µg/L) and in SPM (3,865 µg/g), while in sediment the mean concentration of 2,4,6-trichlorophenol was the highest (3.05 µg/g). The total concentration of 5 chlorophenols (∑CP5) was significantly higher than that of 6 non-chlorophenols (∑NCP6) in all three studied compartments. The phenolic compounds in Weihe River were at moderate levels in water and at high levels in sediment. The ecological risk assessment results indicated that phenolic compounds exhibited a high ecological risk in Weihe River water. In most sites, the distribution coefficient (Kd) (SPM) was much higher than Kd (sediment), which probably suggested fresh phenolic compounds input in Weihe River.


Asunto(s)
Ríos , Contaminantes Químicos del Agua , China , Monitoreo del Ambiente , Sedimentos Geológicos , Material Particulado/análisis , Agua/análisis , Contaminantes Químicos del Agua/análisis
15.
Front Public Health ; 9: 642630, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33842423

RESUMEN

Meteorology and long-term trends in air pollutant concentrations may obscure the results from short-term policies implemented to improve air quality. This study presents changes in CO, NO2, O3, SO2, PM10, and PM2.5 based on their anomalies during the COVID-19 partial (Phase 2) and total (Phase 3) lockdowns in Mexico City (MCMA). To minimise the impact of the air pollutant long-term trends, pollutant anomalies were calculated using as baseline truncated Fourier series, fitted with data from 2016 to 2019, and then compared with those from the lockdown. Additionally, days with stagnant conditions and heavy rain were excluded to reduce the impact of extreme weather changes. Satellite observations for NO2 and CO were used to contrast the ground-based derived results. During the lockdown Phase 2, only NO2 exhibited significant decreases (p < 0.05) of between 10 and 23% due to reductions in motor vehicle emissions. By contrast, O3 increased (p < 0.05) between 16 and 40% at the same sites where NO2 decreased. During Phase 3, significant decreases (p < 0.05) were observed for NO2 (43%), PM10 (20%), and PM2.5 (32%) in response to the total lockdown. Although O3 concentrations were lower in Phase 3 than during Phase 2, those did not decrease (p < 0.05) from the baseline at any site despite the total lockdown. SO2 decreased only during Phase 3 in a near-road environment. Satellite observations confirmed that NO2 decreased and CO stabilised during the total lockdown. Air pollutant changes during the lockdown could be overestimated between 2 and 10-fold without accounting for the influences of meteorology and long-term trends in pollutant concentrations. Air quality improved significantly during the lockdown driven by reduced NO2 and PM2.5 emissions despite increases in O3, resulting in health benefits for the MCMA population. A health assessment conducted suggested that around 588 deaths related to air pollution exposure were averted during the lockdown. Our results show that to reduce O3 within the MCMA, policies must focus on reducing VOCs emissions from non-mobile sources. The measures implemented during the COVID-19 lockdowns provide valuable information to reduce air pollution through a range of abatement strategies for emissions other than from motor vehicles.


Asunto(s)
Contaminación del Aire/análisis , Control de Enfermedades Transmisibles , Monitoreo del Ambiente , Ciudades , Humanos , México/epidemiología , Material Particulado/análisis , Salud Pública
16.
Environ Monit Assess ; 193(5): 251, 2021 Apr 08.
Artículo en Inglés | MEDLINE | ID: mdl-33834306

RESUMEN

Field calibrations of NO2, NO, and PM10 from AQMesh Air Quality Monitors (AQMs) were conducted during a summer and an autumn period in a busy street in a midsize Swedish city. All the three linear calibration procedures studied (postscaled, bisquare, and orthogonal data) significantly reduced the ranges and magnitudes of the performance indicators to yield more reliable results than the raw data. The improvements were sufficient to satisfy the European Union (EU) Data Quality Objective (DQO) for indicative measurements as compared to reference data only for NO2 (above 50 µg m-3) and NO (above 30 µg m-3) during the autumn calibration period. The relatively simple bisquare procedure had the best performance overall. The bisquare procedure improved the root mean square error by the same amount as other studies using complex multivariate calibration methods. Low concentrations of pollutants were measured, far below the EU Environmental Quality Standard thresholds and even satisfying the future goals for the Environmental Quality Objectives. Cleaning the raw data by removing data points in the reference data that were below the reference station limit of detections (and the synchronous data points in the AQM prescaled data) was found to improve the performances of the calibration procedures appreciably. Many NO2 and almost all PM10 data points in this study fell below the AQM limit of detection. These low concentrations will probably be a common problem in many field studies, at least in areas with relatively low air pollution. However, the relative errors were sufficiently low for these data points that they could be interpreted as accurately representing low concentrations and did not need to be removed from the datasets. For the NO2 measurements, a slight periodic error correlated with sunlight and increased ambient temperature was noted. NO measurements correlated strongly with increased traffic.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire , Contaminantes Atmosféricos/análisis , Contaminación del Aire/análisis , Calibración , Monitoreo del Ambiente , Material Particulado/análisis , Estaciones del Año
17.
Sensors (Basel) ; 21(5)2021 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-33800192

RESUMEN

The World Health Organization has estimated that air pollution is a major threat to health, causing approximately nine million premature deaths every year. Each individual has, over their lifetime, a unique exposure to air pollution through their habits, working and living conditions. Medical research requires dedicated tools to assess and understand individual exposure to air pollution in view of investigating its health effects. This paper presents portable sensors produced by the Canarin Project that provides accessible, real time personal exposure data to particulate matter. Our primary results demonstrate the use of portable sensors for the assessment of personal exposure to the different micro-environments attended by individuals, and for inspecting the short-term effects of air pollution through the example of sleep apnea. These findings underscore the necessity of obtaining contextual data in determining environmental exposure and give perspectives for the future of air pollution sensors dedicated to medical research.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire Interior , Contaminación del Aire , Contaminantes Atmosféricos/análisis , Contaminantes Atmosféricos/toxicidad , Contaminación del Aire/análisis , Contaminación del Aire Interior/análisis , Exposición a Riesgos Ambientales/efectos adversos , Monitoreo del Ambiente , Humanos , Material Particulado/análisis , Material Particulado/toxicidad
18.
Artículo en Inglés | MEDLINE | ID: mdl-33805155

RESUMEN

Good quality and completeness of ambient air quality monitoring data is central in supporting actions towards mitigating the impact of ambient air pollution. In South Africa, however, availability of continuous ground-level air pollution monitoring data is scarce and incomplete. To address this issue, we developed and compared different modeling approaches to impute missing daily average particulate matter (PM10) data between 2010 and 2017 using spatiotemporal predictor variables. The random forest (RF) machine learning method was used to explore the relationship between average daily PM10 concentrations and spatiotemporal predictors like meteorological, land use and source-related variables. National (8 models), provincial (32) and site-specific (44) RF models were developed to impute missing daily PM10 data. The annual national, provincial and site-specific RF cross-validation (CV) models explained on average 78%, 70% and 55% of ground-level PM10 concentrations, respectively. The spatial components of the national and provincial CV RF models explained on average 22% and 48%, while the temporal components of the national, provincial and site-specific CV RF models explained on average 78%, 68% and 57% of ground-level PM10 concentrations, respectively. This study demonstrates a feasible approach based on RF to impute missing measurement data in areas where data collection is sparse and incomplete.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire , Contaminantes Atmosféricos/análisis , Contaminación del Aire/análisis , Monitoreo del Ambiente , Material Particulado/análisis , Sudáfrica
19.
Environ Monit Assess ; 193(5): 284, 2021 Apr 19.
Artículo en Inglés | MEDLINE | ID: mdl-33876293

RESUMEN

Approximately 1 billion tons of phosphogypsum (PG), a by-product of the fertilizer industry, are currently stacked in Florida. PG emits radon gas, which is a risk factor for lung cancer and can also increase particulate matter (PM) associated non-cancer mortality in exposed individuals. We measured concentrations of atmospheric radon and particulate matter near PG stacks and their short-term variations at different distances to estimate exposures in nearby communities. Specifically, we measured atmospheric levels of radon, and mass concentrations of PM1, PM2.5, and PM10, and number concentrations of PM0.3, PM0.5, PM1, PM2.5, PM5, and PM10 near three large PG stacks in Florida. Atmospheric radon was collected at distances of 2.5, 5.0, and 7.5 miles downwind from three large PG stacks using charcoal-based kits and measured by liquid scintillation counting. A professional radon monitor was used to take 24-h-average radon reading at 5.0 miles from each stack for comparison purposes. The median (IQR) radon levels were 0.325 (0.150, 0.675), 0.150 (0.150, 0.650), and 0.500 (0.150, 0.700) pCi/L at 2.5, 5, and 7.5 miles, respectively. The median (IQR) PM2.5 levels were 5 (4, 6), 5 (3, 7), and 5 (2, 9) µg/m3 at 2.5, 5, and 7.5 miles, respectively. Non-parametric Kruskal-Wallis test could not detect any association between radon or PM levels and distances (2.5-7 miles) from PG stacks. With scintillation counting, median radon levels detected were above the US Environmental Protection Agency (EPA) recommended standard in some of the sites; however, much higher levels were detected through the more advanced digital monitor. PM2.5 levels were below the US-EPA 24-h average national ambient air quality standard in the study area. We conclude that ambient radon levels near PG stacks could exceed US EPA recommended outdoor standards and do not vary within a short distance from the sources, implying similar exposures in nearby communities.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire , Radón , Contaminantes Atmosféricos/análisis , Contaminación del Aire/análisis , Sulfato de Calcio , Exposición a Riesgos Ambientales/análisis , Monitoreo del Ambiente , Florida , Humanos , Material Particulado/análisis , Fósforo , Radón/análisis
20.
Artículo en Inglés | MEDLINE | ID: mdl-33807925

RESUMEN

We aimed to assess a possible interaction effect between physical activity and particulate air pollution exposure on recurrence of ischemic heart disease (IHD) and stroke. We followed 2221 adult participants comprising first time IHD (1403) and stroke (818) cases from the Västerbotten Intervention Program between 1 January 1990 to 31 December 2013. During mean follow-up times of 5.5 years, 428 and 156 participants developed IHD and stroke recurrence, respectively. PM2.5 concentrations above the median (5.48 µg/m3) were associated with increased risk of IHD and stroke recurrence by 13% (95% CI -17-45%) and 21% (95% CI -19-80%), respectively. These risk increases were however only observed among those that exercised at most once a week at 21% (95% CI -5-50%) and 25% (95% CI -19-90%) for IHD and stroke recurrence, respectively. Higher frequency of exercise at recruitment was positively associated with IHD and stroke recurrence but only the association with IHD recurrence among participants with low residential PM2.5 was statistically significant (96% increased risk (95%-CI 22-215%)). However, no interaction effect between physical activity and PM2.5 exposure was found. Our findings suggest that physical activity may reduce the air pollution exposure associated risk for recurrent cardiovascular disease, likely by reducing the inflammatory response.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire , Enfermedades Cardiovasculares , Adulto , Contaminantes Atmosféricos/análisis , Contaminación del Aire/efectos adversos , Contaminación del Aire/análisis , Enfermedades Cardiovasculares/epidemiología , Exposición a Riesgos Ambientales , Ejercicio Físico , Humanos , Material Particulado/efectos adversos , Material Particulado/análisis
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