606 results match your criteria Atmospheric Environment[Journal]

Exploration of PM mass, source, and component-related factors that might explain heterogeneity in daily PM-mortality associations across the United States.

Atmos Environ (1994) 2021 Oct 31;262. Epub 2021 Jul 31.

U.S. Environmental Protection Agency, Office of Research and Development, Research Triangle Park, NC.

Multi-city epidemiologic studies examining short-term (daily) differences in fine particulate matter (PM) provide evidence of substantial spatial heterogeneity in city-specific mortality risk estimates across the United States. Because PM is a mixture of particles, both directly emitted from sources or formed through atmospheric reactions, some of this heterogeneity may be due to regional variations in PM toxicity. Using inverse variance weighted linear regression, we examined change in percent change in mortality in association with 24 "exposure" determinants representing three basic groupings based on potential explanations for differences in PM toxicity - size, source, and composition. Read More

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October 2021

Insights from Application of a Hierarchical Spatio-Temporal Model to an Intensive Urban Black Carbon Monitoring Dataset.

Atmos Environ (1994) 2022 May 23;277. Epub 2022 Mar 23.

Department of Biostatistics, University of Washington, Seattle, WA.

Existing regulatory pollutant monitoring networks rely on a small number of centrally located measurement sites that are purposefully sited away from major emission sources. While informative of general air quality trends regionally, these networks often do not fully capture the local variability of air pollution exposure within a community. Recent technological advancements have reduced the cost of sensors, allowing air quality monitoring campaigns with high spatial resolution. Read More

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Unexpected rise of atmospheric secondary aerosols from biomass burning during the COVID-19 lockdown period in Hangzhou, China.

Atmos Environ (1994) 2022 Jun 28;278:119076. Epub 2022 Mar 28.

State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, 310027, China.

After the global outbreak of COVID-19, the Chinese government took many measures to control the spread of the virus. The measures led to a reduction in anthropogenic emissions nationwide. Data from a single particle aerosol mass spectrometer in an eastern Chinese megacity (Hangzhou) before, during, and after the COVID-19 lockdown (5 January to February 29, 2020) was used to understand the effect lockdown had on atmospheric particles. Read More

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Evaluation of NOx emissions before, during, and after the COVID-19 lockdowns in China: A comparison of meteorological normalization methods.

Atmos Environ (1994) 2022 Jun 25;278:119083. Epub 2022 Mar 25.

Department of Environmental Science and Engineering, Sichuan University, Chengdu, Sichuan, 610065, China.

Meteorological normalization refers to the removal of meteorological effects on air pollutant concentrations for evaluating emission changes. There currently exist various meteorological normalization methods, yielding inconsistent results. This study aims to identify the state-of-the-art method of meteorological normalization for characterizing the spatiotemporal variation of NOx emissions caused by the COVID-19 pandemic in China. Read More

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Impact of the COVID-19 on the vertical distributions of major pollutants from a tower in the Pearl River Delta.

Atmos Environ (1994) 2022 May 20;276:119068. Epub 2022 Mar 20.

School of Atmospheric Sciences, Sun Yat-Sen University, Zhuhai, 519082, PR China.

The outbreak of the 2019 novel coronavirus (COVID-19) had a large impact on human health and socio-economics worldwide. The lockdown implemented in China beginning from January 23, 2020 led to sharp reductions in human activities and associated emissions. The declines in primary pollution provided a unique opportunity to examine the relationship between anthropogenic emissions and air quality. Read More

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Nonlinear influence of winter meteorology and precursor on PM based on mathematical and numerical models: A COVID-19 and Winter Olympics case study.

Atmos Environ (1994) 2022 Jun 23;278:119072. Epub 2022 Mar 23.

Key Laboratory of Beijing on Regional Air Pollution Control, Faculty of Environment and Life, Beijing University of Technology, Beijing, 100124, China.

Air pollution during the COVID-19 epidemic in Beijing and its surrounding regions has received substantial attention. We collected observational data, including air pollutant concentrations and meteorological parameters, during January and February from 2018 to 2021. A statistical and a numerical model were applied to identify the formation of air pollution and the impact of emission reduction on air quality. Read More

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Evaluation of small form factor, filter-based PM samplers for temporary non-regulatory monitoring during wildland fire smoke events.

Atmos Environ (1994) 2021 Nov;265:1-8

US EPA, Office of Research and Development, Research Triangle Park, NC, USA.

Wildland fire activity and associated emission of particulate matter air pollution is increasing in the United States over the last two decades due primarily to a combination of increased temperature, drought, and historically high forest fuel loading. The regulatory monitoring networks in the Unites States are mostly concentrated in larger population centers where anthropogenic air pollution sources are concentrated. Smaller population centers in areas more likely to be impacted by wildland fire smoke in many instances lack adequate observational air quality data. Read More

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November 2021

Characteristic changes of ozone and its precursors in London during COVID-19 lockdown and the ozone surge reason analysis.

Atmos Environ (1994) 2022 Mar 4;273:118980. Epub 2022 Feb 4.

School of Geosciences, The University of Edinburgh, Edinburgh, EH9 3FF, United Kingdom.

The London COVID-19 lockdown reduced emissions from anthropogenic sources, providing unique conditions for air contamination research. This research uses tropospheric ozone (O), volatile organic compounds (VOCs) and NOx (NO+NO) hourly monitoring data at the London Marylebone Road station from 2001 to 2020 to investigate the effects of lockdown on (O) and its precursors. Both NOx and VOCs pollution showed a decreasing trend between 2001 and 2021, with a gradual increase in O in contrast. Read More

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A comprehensive study of the COVID-19 impact on PM levels over the contiguous United States: A deep learning approach.

Atmos Environ (1994) 2022 Mar 14;272:118944. Epub 2022 Jan 14.

Oak Ridge Associated Universities, Oak Ridge, TN, 37830, USA.

We investigate the impact of the COVID-19 outbreak on PM levels in eleven urban environments across the United States: Washington DC, New York, Boston, Chicago, Los Angeles, Houston, Dallas, Philadelphia, Detroit, Phoenix, and Seattle. We estimate daily PM levels over the contiguous U.S. Read More

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Per- and Polyfluoroalkyl Substances (PFASs) in Airborne Particulate Matter (PM) Emitted During Floor Waxing: A Pilot Study.

Atmos Environ (1994) 2022 Jan 10;268. Epub 2021 Nov 10.

Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.

Per- and polyfluoroalkyl substances (PFASs), with their water- and heat-resistant properties, have been widely used in industrial and consumer products, including floor waxes. Adverse health effects are associated with PFAS exposures (e.g. Read More

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January 2022

The effect of the 2020 COVID-19 lockdown on atmospheric black carbon levels in northeastern Greenland.

Atmos Environ (1994) 2022 Jan 15;269:118853. Epub 2021 Nov 15.

Department of Environmental Science, iClimate, Arctic Research Center, Aarhus University, Roskilde, Denmark.

The outbreak of SARS-CoV-2 and subsequent spread of the disease COVID-19 became classified as a pandemic in March of 2020, leading to global safety measures introduced to limit the impact of the virus. This combination of safety measures has become commonly referred to as "lockdown". The associated industry and lifestyle changes led to reductions in the anthropogenic emission of atmospheric pollutants such as black carbon (BC), which is transported from the mid-latitudes into the Arctic during the winter and spring. Read More

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January 2022

Impact of near-surface turbulence on PM concentration in Chengdu during the COVID-19 pandemic.

Atmos Environ (1994) 2022 Jan 11;268:118848. Epub 2021 Nov 11.

State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing, China.

The role of meteorological conditions has long been recognized in modulating regional air quality. The impact of near-surface turbulence, nevertheless, remains poorly understood. To curb the spread of COVID-19, a variety of lockdown measures were implemented, providing us an unprecedented opportunity to examine the joint impact of emission control and meteorology on regional air quality. Read More

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January 2022

Particle composition, sources and evolution during the COVID-19 lockdown period in Chengdu, southwest China: Insights from single particle aerosol mass spectrometer data.

Atmos Environ (1994) 2022 Jan 9;268:118844. Epub 2021 Nov 9.

Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu, 611756, China.

In order to investigate the effects of the Coronavirus Disease 2019 (COVID-19) lockdown on air quality in cities in southwest China, a single particle aerosol mass spectrometer (SPAMS) and other online equipments were used to measure the air pollution in Chengdu, one of the megacities in this area, before and during the lockdown period. It was found that the concentrations of fine particulate matter (PM), nitric oxide (NO), nitrogen dioxide (NO), sulfur dioxide (SO) and carbon monoxide (CO) decreased by 38.6%, 77. Read More

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January 2022

Impacts of COVID-19 on air quality in mid-eastern China: An insight into meteorology and emissions.

Atmos Environ (1994) 2021 Dec 24;266:118750. Epub 2021 Sep 24.

Department of Environmental Art Engineering, Nanjing Technical Vocational College, Nanjing 210019, China.

The coronavirus disease (COVID-19) spread rapidly worldwide in the first half of 2020. Stringent national lockdown policies imposed by China to prevent the spread of the virus reduced anthropogenic emissions and improved air quality. A weather research and forecasting model coupled with chemistry was applied to evaluate the impact of meteorology and emissions on air quality during the COVID-19 outbreak (from January 23 to February 29, 2020) in mid-eastern China. Read More

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December 2021

Nonlinear response of nitrate to NO reduction in China during the COVID-19 pandemic.

Atmos Environ (1994) 2021 Nov 8;264:118715. Epub 2021 Sep 8.

Joint International Research Laboratory of Atmospheric and Earth System Sciences, School of Atmospheric Sciences, Nanjing University, Nanjing, 210023, China.

In recent years, nitrate plays an increasingly important role in haze pollution and strict emission control seems ineffective in reducing nitrate pollution in China. In this study, observations of gaseous and particulate pollutants during the COVID-19 lockdown, as well as numerical modelling were integrated to explore the underlying causes of the nonlinear response of nitrate mitigation to nitric oxides (NO) reduction. We found that, due to less NO titration effect and the transition of ozone (O) formation regime caused by NO emissions reduction, a significant increase of O (by ∼ 69%) was observed during the lockdown period, leading to higher atmospheric oxidizing capacity and facilitating the conversion from NO to oxidation products like nitric acid (HNO). Read More

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November 2021

High-volume sampler for size-selective sampling of bioaerosols including viruses.

Atmos Environ (1994) 2021 Nov 12;265:118720. Epub 2021 Sep 12.

School of Mechanical Engineering, Hanyang University, Seoul, 04763, South Korea.

Owing to the recent global spread of the new coronavirus SARS-CoV-2, the development of technology to effectively detect viruses in crowded public places is urgently needed. In this study, a three-stage high-volume bioaerosol sampler was developed for the size-selective sampling of bioaerosols through the suction of air at a high flow rate of 1000 L/min. In stage 1, an omnidirectional inlet cyclone separator that can draw air from all directions was applied to collect bioaerosols larger than 10 μm in the collection fluid. Read More

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November 2021

Simulations of dispersion through an irregular urban building array.

Atmos Environ (1994) 2021 Aug;258

Jacobs Technology, Inc. (JTI), Research Triangle Park, NC, USA.

Following the release of a harmful substance within an urban environment, buildings and street canyons create complex flow regimes that affect dispersion and localized effluent concentrations. While some fast-response dispersion models can capture the effects caused by individual buildings, further research is required to refine urban characterizations such as plume channeling and spreading, and initial dispersion, especially within the presence of a nonhomogeneous array of structures. Field, laboratory, and modeling experiments that simulate urban or industrial releases are critical in advancing current dispersion models. Read More

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Impacts of the COVID-19 economic slowdown on ozone pollution in the U.S.

Atmos Environ (1994) 2021 Nov 4;264:118713. Epub 2021 Sep 4.

Harvard University, Department of Engineering and Applied Science, Cambridge, MA, USA.

In this work, we use observations and experimental emissions in a version of NOAA's National Air Quality Forecasting Capability to show that the COVID-19 economic slowdown led to disproportionate impacts on near-surface ozone concentrations across the contiguous U.S. (CONUS). Read More

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November 2021

Atmospheric nitrogen deposition in the Chesapeake Bay watershed: A history of change.

Atmos Environ (1994) 2021 Apr;251(15):1-118277

U.S. Geological Survey, Annapolis, MD, USA.

The Chesapeake Bay watershed has been the focus of pioneering studies of the role of atmospheric nitrogen (N) deposition as a nutrient source and driver of estuarine trophic status. Here, we review the history and evolution of scientific investigations of the role of atmospheric N deposition, examine trends from wet and dry deposition networks, and present century-long (1950-2050) atmospheric N deposition estimates. Early investigations demonstrated the importance of atmospheric deposition as an N source to the Bay, providing 25%-40% among all major N sources. Read More

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Quantifying wintertime O and NO formation with relevance vector machines.

Atmos Environ (1994) 2021 Aug;259:1-118538

Office of Research and Development, United States Environmental Protection Agency, 109 T.W. Alexander Drive, Research Triangle Park, NC 27711, United States.

This paper uses a machine learning model called a relevance vector machine (RVM) to quantify ozone (O) and nitrogen oxides (NO) formation under wintertime conditions. Field study measurements were based on previous work described by Olson et al. (2019), where continuous measurements were reported from a wintertime field study in Utah. Read More

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Improving Estimates of PM Concentration and Chemical Composition by Application of High Spectral Resolution Lidar (HSRL) and Creating Aerosol Types from Chemistry (CATCH) Algorithm.

Atmos Environ (1994) 2021 Apr;250

NASA Langley Research Center, Hampton, VA.

Improved characterization of ambient PM mass concentration and chemical speciation is a topic of interest in air quality and climate sciences. Over the past decades, considerable efforts have been made to improve ground-level PM using remotely sensed data. Here we present two new approaches for estimating atmospheric PM and chemical composition based on the High Spectral Resolution Lidar (HSRL)-retrieved aerosol extinction values and types and Creating Aerosol Types from Chemistry (CATCH)-derived aerosol chemical composition. Read More

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Wildland Fire Emission Sampling at Fishlake National Forest, Utah Using an Unmanned Aircraft System.

Atmos Environ (1994) 2021 Feb;247:118193

U.S. Forest Service, Pacific Wildland Forest Service Laboratory, 400 North 34 Street, Seattle, WA 98103, USA.

Emissions from a stand replacement prescribed burn were sampled using an unmanned aircraft system (UAS, or "drone") in Fishlake National Forest, Utah, U.S.A. Read More

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February 2021

Impact of the first induced COVID-19 lockdown on air quality in Israel.

Atmos Environ (1994) 2021 Oct 24;262:118627. Epub 2021 Jul 24.

Department of Geography, The Hebrew University, Jerusalem, Israel.

The coronavirus disease 2019 (COVID-19) induced a lockdown that has resulted in a sharp reduction in air and motor traffic and industrial activities. This in turn led to a reduction in air pollution around the world. It is important to quantify the extent of that reduction in order to estimate the weight of the impact of air and motor traffic and industrial activities over the total variation of air quality. Read More

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October 2021

Source Apportionment of Environmental Combustion Sources using Excitation Emission Matrix Fluorescence Spectroscopy and Machine Learning.

Atmos Environ (1994) 2021 Aug 31;259. Epub 2021 May 31.

Department of Chemical Engineering, University of Washington, Seattle WA, United States.

The link between particulate matter (PM) air pollution and negative health effects is well-established. Air pollution was estimated to cause 4.9 million deaths in 2017 and PM was responsible for 94% of these deaths. Read More

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An observation approach in evaluation of ozone production to precursor changes during the COVID-19 lockdown.

Atmos Environ (1994) 2021 Oct 14;262:118618. Epub 2021 Jul 14.

Institute for Environmental and Climate Research, Jinan University, Guangzhou, 511443, China.

The increase of surface ozone during the Corona Virus Disease 2019 (COVID-19) lockdown in China has aroused great concern. In this study, we combine 1.5 years of measurements for ozone, volatile organic compounds (VOCs), and nitrogen oxide (NO) at four sites to investigate the effect of COVID-19 lockdown on surface ozone in Dongguan, an industrial city in southern China. Read More

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October 2021

Using Gas-Phase Air Quality Sensors to Disentangle Potential Sources in a Los Angeles Neighborhood.

Atmos Environ (1994) 2020 Jul 6;233. Epub 2020 May 6.

Mechanical Engineering University of Colorado Boulder.

In the late summer of 2016, our team deployed a network of low-cost air quality sensing systems in partnership with community-based organizations in a neighborhood in South Los Angeles, California. Residents of this community were concerned about possible emissions from local oil and gas activity, however in addition to these potential emissions, the neighborhood is also subject to a complex mixture of pollutants from other nearby sources including major highways. For this deployment, metal-oxide VOC sensors were quantified to provide methane (CH) and total non-methane hydrocarbon (TNMHCs) concentration estimates. Read More

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Impact of various air mass types on cloud condensation nuclei concentrations along coastal southeast Florida.

Atmos Environ (1994) 2021 Jun 29;254. Epub 2021 Mar 29.

Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, USA.

Coastal southeast Florida experiences a wide range of aerosol conditions, including African dust, biomass burning (BB) aerosols, as well as sea salt and other locally-emitted aerosols. These aerosols are important sources of cloud condensation nuclei (CCN), which play an essential role in governing cloud radiative properties. As marine environments dominate the surface of Earth, CCN characteristics in coastal southeast Florida have broad implications for other regions with the added feature that this site is perturbed by both natural and anthropogenic emissions. Read More

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On the airborne transmission of SARS-CoV-2 and relationship with indoor conditions at a hospital.

Atmos Environ (1994) 2021 Sep 21;261:118563. Epub 2021 Jun 21.

Air Pollution and Respiratory Diseases Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.

The limited knowledge about the mechanism of SARS-CoV-2 transmission is a current challenge on a global scale. Among possible transmission routes, air transfer of the virus is thought to be prominent. To investigate this further, measurements were conducted at Razi hospital in Ahvaz, Iran, which was selected to treat COVID-19 severe cases in the Khuzestan province. Read More

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September 2021

An investigation of the impacts of a successful COVID-19 response and meteorology on air quality in New Zealand.

Atmos Environ (1994) 2021 Jun 11;254:118322. Epub 2021 Mar 11.

Ministry for the Environment, Auckland, New Zealand.

The COVID-19 pandemic brought about national restrictions on people's movements, in effect commencing a socially engineered transport emission reduction experiment. In New Zealand during the most restrictive alert level (Level 4), roadside concentrations of nitrogen dioxide (NO) were reduced 48-54% compared to Business-as-usual (BAU) values. NO concentrations rapidly returned to near mean levels as the alert levels decreased and restrictions eased. Read More

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Data mining approaches to understanding the formation of secondary organic aerosol.

Atmos Environ (1994) 2021 May;252

Office of Research and Development, United States Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States.

This research used data mining approaches to better understand factors affecting the formation of secondary organic aerosol (SOA). Although numerous laboratory and computational studies have been completed on SOA formation, it is still challenging to determine factors that most influence SOA formation. Experimental data were based on previous work described by Offenberg et al. Read More

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