31 results match your criteria Atmosphere[Journal]

Predicting the Nonlinear Response of PM and Ozone to Precursor Emission Changes with a Response Surface Model.

Atmosphere (Basel) 2021 Aug;12(8):1-1044

Center for Environmental Measurement and Modeling, U.S. Environmental Protection Agency, Research Triangle Park, Durham, NC 27711, USA.

Reducing PM and ozone concentrations is important to protect human health and the environment. Chemical transport models, such as the Community Multiscale Air Quality (CMAQ) model, are valuable tools for exploring policy options for improving air quality but are computationally expensive. Here, we statistically fit an efficient polynomial function in a response surface model (pf-RSM) to CMAQ simulations over the eastern U. Read More

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Application of Bayesian Additive Regression Trees for Estimating Daily Concentrations of PM Components.

Atmosphere (Basel) 2020 Nov 16;11(11). Epub 2020 Nov 16.

Department of Biostatistics and Bioinformatics, Emory University, Atlanta, GA 30322, USA.

Bayesian additive regression tree (BART) is a recent statistical method that combines ensemble learning and nonparametric regression. BART is constructed under a probabilistic framework that also allows for model-based prediction uncertainty quantification. We evaluated the application of BART in predicting daily concentrations of four fine particulate matter (PM) components (elemental carbon, organic carbon, nitrate, and sulfate) in California during the period 2005 to 2014. Read More

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November 2020

Source Apportionment of Aerosol at a Coastal Site and Relationships with Precipitation Chemistry: A Case Study over the Southeast United States.

Atmosphere (Basel) 2020 Nov 10;11(11):1212. Epub 2020 Nov 10.

Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85721, USA.

This study focuses on the long-term aerosol and precipitation chemistry measurements from colocated monitoring sites in Southern Florida between 2013 and 2018. A positive matrix factorization (PMF) model identified six potential emission sources impacting the study area. The PMF model solution yielded the following source concentration profiles: (i) combustion; (ii) fresh sea salt; (iii) aged sea salt; (iv) secondary sulfate; (v) shipping emissions; and (vi) dust. Read More

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November 2020

Tidal Wave-Driven Variability in the Mars Ionosphere-Thermosphere System.

Atmosphere (Basel) 2020 May 19;11(5):521. Epub 2020 May 19.

Climate and Space Sciences and Engineering Department, University of Michigan, Ann Arbor, MI 48109, USA.

In order to further evaluate the behavior of ionospheric variations at Mars, we investigate the Martian ionosphere-thermosphere (IT) perturbations associated with non-migrating thermal tides using over four years of Mars Atmosphere and Volatile Evolution (MAVEN) in situ measurements of the IT electron and neutral densities. The results are consistent with those of previous studies, namely strong correlation between the tidal perturbations in electron and neutral densities on the dayside at altitudes ~150-185 km, as expected from photochemical theory. In addition, there are intervals during which this correlation extends to higher altitudes, up to ~270 km, where diffusive transport of plasma plays a dominant role over photochemical processes. Read More

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Variability in Observation-based Onroad Emission Constraints from a Near-road Environment.

Atmosphere (Basel) 2020 Nov;11(11):1243

Center for Environmental Measurement and Modeling, US EPA, RTP, 27711, NC.

This study uses Las Vegas near-road measurements of carbon monoxide (CO) and nitrogen oxides (NO) to test the consistency of onroad emission constraint methodologies. We derive commonly used CO to NO ratios (ΔCO:ΔNO) from cross-road gradients and from linear regression using ordinary least squares (OLS) regression and orthogonal regression. The CO to NO ratios are used to infer NO emission adjustments for a priori emissions estimates from EPA's MOtor Vehicle Emissions Simulator (MOVES) model assuming unbiased CO. Read More

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November 2020

Data assimilation of ambient concentrations of multiple air pollutants using an emission-concentration response modeling framework.

Atmosphere (Basel) 2020 ;11(12)

State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China.

Data assimilation for multiple air pollutant concentrations has become an important need for modeling air quality attainment, human exposure and related health impacts, especially in China that experiences both PM and O pollution. Traditional data assimilation or fusion methods are mainly focused on individual pollutants, and thus cannot support simultaneous assimilation for both PM and O. To fill the gap, this study proposed a novel multipollutant assimilation method by using an emission-concentration response model (noted as RSM-assimilation). Read More

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January 2020

Gas-Phase Reaction of -2-Methyl-2-butenal with Cl: Kinetics, Gaseous Products, and SOA Formation.

Atmosphere (Basel) 2020 Jul 5;11(7):715. Epub 2020 Jul 5.

Instituto de Investigación en Combustión y Contaminación Atmosférica, Universidad de Castilla-La Mancha, Camino de Moledores s/n, 13071 Ciudad Real, Spain.

The gas-phase reaction between -2-methyl-2-butenal and chlorine (Cl) atoms has been studied in a simulation chamber at 298 ± 2 K and 760 ± 5 Torr of air under free-NO conditions. The rate coefficient of this reaction was determined as = (2.45 ± 0. Read More

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Regional and Urban-Scale Environmental Influences of Oceanic DMS Emissions over Coastal China Seas.

Atmosphere (Basel) 2020 Aug;11(8):1-849

Department of Atmospheric Chemistry and Climate, Institute of Physical Chemistry Rocasolano, CSIC, 28006 Madrid, Spain.

Marine biogenic dimethyl sulfide (DMS) is an important natural source of sulfur in the atmosphere, which may play an important role in air quality. In this study, the WRF-CMAQ model is employed to assess the impact of DMS on the atmospheric environment at the regional scale of eastern coastal China and urban scale of Shanghai in 2017. A national scale database of DMS concentration in seawater is established based on the historical DMS measurements in the Yellow Sea, the Bohai Sea and the East China Sea in different seasons during 2009~2017. Read More

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A New Monitoring Effort for Asia: The Asia Pacific Mercury Monitoring Network (APMMN).

Atmosphere (Basel) 2019 Sep 21;10(9):481. Epub 2019 Aug 21.

Department of Atmospheric Sciences, National Central University, 300 Jhong-Da Rd, Taoyuan 32001, Taiwan.

The Asia Pacific Mercury Monitoring Network (APMMN) cooperatively measures mercury in precipitation in a network of sites operating in Asia and the Western Pacific region. The network addresses significant data gaps in a region where mercury emission estimates are the highest globally, and available measurement data are limited. The reduction of mercury emissions under the Minamata Convention on Mercury also justifies the need for continent-wide and consistent observations that can help determine the magnitude of the problem and assess the efficacy of reductions over time. Read More

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September 2019

Quantifying the Public Health Benefits of Reducing Air Pollution: Critically Assessing the Features and Capabilities of WHO's AirQ+ and U.S. EPA's Environmental Benefits Mapping and Analysis Program - Community Edition (BenMAP - CE).

Atmosphere (Basel) 2020 May;11(5):1-15

European Centre for Environment and Health, World Health Organization Regional Office for Europe, Bonn, Germany.

Scientific evidence spanning experimental and epidemiologic studies has shown that air pollution exposures can lead to a range of health effects. Quantitative approaches that allow for the estimation of the adverse health impacts attributed to air pollution enable researchers and policy analysts to convey the public health impact of poor air quality. Multiple tools are currently available to conduct such analyses, which includes software packages designed by the World Health Organization (WHO): AirQ+, and the U. Read More

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Incorporation of Remote PM Concentrations into the Downscaler Model for Spatially Fused Air Quality Surfaces.

Atmosphere (Basel) 2020 Jan;11(103)

Office of Air Quality Planning and Standards, Environmental Protection Agency, Research Triangle Park, NC 27711, USA.

The United States Environmental Protection Agency (EPA) has implemented a Bayesian spatial data fusion model called the Downscaler (DS) model to generate daily air quality surfaces for PM across the contiguous U.S. Previous implementations of DS relied on monitoring data from EPA's Air Quality System (AQS) network, which is largely concentrated in urban areas. Read More

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January 2020

Fine-Scale Modeling of Individual Exposures to Ambient PM, EC, NO, CO for the Coronary Artery Disease and Environmental Exposure (CADEE) Study.

Atmosphere (Basel) 2020 Jan;11(1):1-65

Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Chapel Hill, NC 27514, USA.

Air pollution epidemiological studies often use outdoor concentrations from central-site monitors as exposure surrogates, which can induce measurement error. The goal of this study was to improve exposure assessments of ambient fine particulate matter (PM), elemental carbon (EC), nitrogen oxides (NO), and carbon monoxide (CO) for a repeated measurements study with 15 individuals with coronary artery disease in central North Carolina called the Coronary Artery Disease and Environmental Exposure (CADEE) Study. We developed a fine-scale exposure modeling approach to determine five tiers of individual-level exposure metrics for PM, EC, NO, CO using outdoor concentrations, on-road vehicle emissions, weather, home building characteristics, time-locations, and time-activities. Read More

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January 2020

The establishment of the Household Air Pollution Consortium (HAPCO).

Atmosphere (Basel) 2019 Jul 23;10(7). Epub 2019 Jul 23.

Division of Epidemiology and Prevention, Aichi Cancer Center Research Institute; Nagoya, 464-8681, Japan.

Household air pollution (HAP) is of public health concern with ~3 billion people worldwide (including >15 million in the US) exposed. HAP from coal use is a human lung carcinogen, yet the epidemiological evidence on carcinogenicity of HAP from biomass use, primarily wood, is not conclusive. To robustly assess biomass's carcinogenic potential, prospective studies of individuals experiencing a variety of HAP exposures are needed. Read More

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Contribution of Satellite-Derived Aerosol Optical Depth PM Bayesian Concentration Surfaces to Respiratory-Cardiovascular Chronic Disease Hospitalizations in Baltimore, Maryland.

Atmosphere (Basel) 2020 18;11(2):209. Epub 2020 Feb 18.

I. M. Systems Group, 5825 University Research Ct, Suite 3250, College Park, MD 20740, USA.

The fine particulate matter baseline (PMB), which includes PM monitor readings with Community Multiscale Air Quality (CMAQ) model predictions, using the Hierarchical Bayesian Model (HBM), is less accurate in rural areas without monitors. To address this issue, an upgraded HBM was used to form four experimental aerosol optical depth (AOD)-PM concentration surfaces. A case-crossover design and conditional logistic regression evaluated the contribution of the AOD-PM surfaces and PMB to four respiratory-cardiovascular hospital events in all 99 12 km CMAQ grids, and in grids with and without ambient air monitors. Read More

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February 2020

Mapping Modeled Exposure of Wildland Fire Smoke for Human Health Studies in California.

Atmosphere (Basel) 2019 Jun 4;10(6). Epub 2019 Jun 4.

Michigan Tech Research Institute, Michigan Technological University, Ann Arbor, MI, 48105 USA.

Wildland fire smoke exposure affects a broad proportion of the U.S. population and is increasing due to climate change, settlement patterns and fire seclusion. Read More

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Combining Dispersion Modeling and Monitoring Data for Community-Scale Air Quality Characterization.

Atmosphere (Basel) 2019 ;10(10):1-610

Institute for the Environment, University of North Carolina at Chapel Hill, Chapel Hill, NC 27517, USA.

Spatially and temporally resolved air quality characterization is critical for community-scale exposure studies and for developing future air quality mitigation strategies. Monitoring-based assessments can characterize local air quality when enough monitors are deployed. However, modeling plays a vital role in furthering the understanding of the relative contributions of emissions sources impacting the community. Read More

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January 2019

Volatile Organic Compound Emissions from Prescribed Burning in Tallgrass Prairie Ecosystems.

Atmosphere (Basel) 2019 ;10(8):1-464

Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27709, USA.

Prescribed pasture burning plays a critical role in ecosystem maintenance in tallgrass prairie ecosystems and may contribute to agricultural productivity but can also have negative impacts on air quality. Volatile organic compound (VOC) concentrations were measured immediately downwind of prescribed tallgrass prairie fires in the Flint Hills region of Kansas, United States. The VOC mixture is dominated by alkenes and oxygenated VOCs, which are highly reactive and can drive photochemical production of ozone downwind of the fires. Read More

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January 2019

Carbonaceous Particulate Matter Emitted from a Pellet-Fired Biomass Boiler.

Atmosphere (Basel) 2019 Sep;10(9):536

Senior Environmental Employment (SEE) Program, Washington, DC 20460, USA.

Biomass pellets are a source of renewable energy; although, the air pollution and exposure risks posed by the emissions from burning pellets in biomass boilers (BBs) are uncertain. The present study examines the organic species in fine particle matter (PM) emissions from an BB firing switchgrass (SwG) and hardwood (HW) biomass pellets using different test cycles. The organic and elemental carbon (OC and EC) content and select semivolatile organic compounds (SVOCs) in filter-collected PM were identified and quantified using thermal-optical analysis and gas chromatography-mass spectrometry (GC-MS), respectively. Read More

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September 2019

Ambient Mercury Observations near a Coal-Fired Power Plant in a Western U.S. Urban Area.

Atmosphere (Basel) 2019 ;10(4):176

Colorado Department of Public Health and Environment, Air Pollution Control Division, Glendale, CO 80246, USA.

We report on the continuous ambient measurements of total gaseous mercury (TGM) and several ancillary air quality parameters that were collected in Colorado Springs, CO. This urban area, which is located adjacent to the Front Range of the Rocky Mountains, is the second largest metropolitan area in Colorado and has a centrally located coal-fired power plant that installed mercury (Hg) emission controls the year prior to our study. There are few other Hg point sources within the city. Read More

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January 2019

Review of Sunset OC/EC Instrument Measurements During the EPA's Sunset Carbon Evaluation Project.

Atmosphere (Basel) 2019 ;10(5):287

U.S. Environmental Protection Agency, Office of Air Quality Planning and Standards, Ambient Air Monitoring Group, Mail Code C304-06, Research Triangle Park, NC 27711, USA.

To evaluate the feasibility of the Sunset semicontinuous organic and elemental carbon (OC/EC) monitor, the U.S. Environmental Protection Agency (EPA) sponsored the deployment of this monitor at Chemical Speciation Network (CSN) sites with OC and EC measurements via quartz fiber filter collection in Chicago, Illinois; Houston, Texas; Las Vegas, Nevada; St. Read More

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January 2019

The Fire and Smoke Model Evaluation Experiment-A Plan for Integrated, Large Fire-Atmosphere Field Campaigns.

Atmosphere (Basel) 2019 ;10(2):66

Desert Research Institute, 2215 Raggio Parkway, Reno, NV 89512, USA.

The Fire and Smoke Model Evaluation Experiment (FASMEE) is designed to collect integrated observations from large wildland fires and provide evaluation datasets for new models and operational systems. Wildland fire, smoke dispersion, and atmospheric chemistry models have become more sophisticated, and next-generation operational models will require evaluation datasets that are coordinated and comprehensive for their evaluation and advancement. Integrated measurements are required, including ground-based observations of fuels and fire behavior, estimates of fire-emitted heat and emissions fluxes, and observations of near-source micrometeorology, plume properties, smoke dispersion, and atmospheric chemistry. Read More

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January 2019

Impact of snow-darkening by deposition of light-absorbing aerosols on snow cover in the Himalaya-Tibetan-Plateau and influence on the Asian Summer monsoon: A possible mechanism for the Blanford Hypothesis.

Atmosphere (Basel) 2018 Nov 12;9(11):438. Epub 2018 Nov 12.

Climate and Radiation Laboratory, NASA/Goddard Space Flight Center.

The impact of snow darkening by deposition of light absorbing aerosols (LAAs) on snow cover over the Himalaya-Tibetan-Plateau (HTP) and influence on the Asian summer monsoon are investigated using the NASA Goddard Earth Observing System Model Version 5 (GEOS-5). We find that during April-May-June, deposition of LAAs on snow leads to a reduction in surface albedo, initiating a sequence of feedback processes, starting with increased net surface solar radiation, rapid snowmelt in HTP and warming of the surface and upper troposphere, followed by enhanced low-level southwesterlies and increased dust loading over the Himalayas-Indo-Gangetic Plain. The warming is amplified by increased dust aerosol heating, and subsequently amplified by latent heating from enhanced precipitation over the Himalaya foothills and northern India, via the Elevated Heat Pump (EHP) effect during June-July-August. Read More

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November 2018

The Global Precipitation Climatology Project (GPCP) Monthly Analysis (New Version 2.3) and a Review of 2017 Global Precipitation.

Atmosphere (Basel) 2018 7;9(4). Epub 2018 Apr 7.

Yonsei University, Seoul, South Korea.

The new Version 2.3 of the GPCP Monthly analysis is described in terms of changes made to improve the homogeneity of the product, especially after 2002. These changes include corrections to cross calibration of satellite data inputs and updates to the gauge analysis. Read More

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Interpreting Mobile and Handheld Air Sensor Readings in Relation to Air Quality Standards and Health Effect Reference Values: Tackling the Challenges.

Atmosphere (Basel) 2017 21;8(10):182. Epub 2017 Sep 21.

Environmental Protection Agency, Research Triangle Park, NC 27711, USA.

The US Environmental Protection Agency (EPA) and other federal agencies face a number of challenges in interpreting and reconciling short-duration (seconds to minutes) readings from mobile and handheld air sensors with the longer duration averages (hours to days) associated with the National Ambient Air Quality Standards (NAAQS) for the criteria pollutants-particulate matter (PM), ozone, carbon monoxide, lead, nitrogen oxides, and sulfur oxides. Similar issues are equally relevant to the hazardous air pollutants (HAPs) where chemical-specific health effect reference values are the best indicators of exposure limits; values which are often based on a lifetime of continuous exposure. A multi-agency, staff-level Air Sensors Health Group (ASHG) was convened in 2013. Read More

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September 2017

Comparison of Five Modeling Approaches to Quantify and Estimate the Effect of Clouds on the Radiation Amplification Factor (RAF) for Solar Ultraviolet Radiation.

Eric S Hall

Atmosphere (Basel) 2017 ;8(8):153

National Exposure Research Laboratory, Office of Research and Development, US Environmental Protection Agency, Mail Drop E205-03, 109 T. W. Alexander Drive, Research Triangle Park, NC 27711, USA.

A generally accepted value for the Radiation Amplification Factor (RAF), with respect to the erythemal action spectrum for sunburn of human skin, is -1.1, indicating that a 1.0% increase in stratospheric ozone leads to a 1. Read More

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January 2017

Frequency and Character of Extreme Aerosol Events in the Southwestern United States: A Case Study Analysis in Arizona.

Atmosphere (Basel) 2016 Jan 23;7(1). Epub 2015 Dec 23.

Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ 85721, USA; Department of Hydrology and Atmospheric Sciences, University of Arizona, Tucson, AZ 85721, USA.

This study uses more than a decade's worth of data across Arizona to characterize the spatiotemporal distribution, frequency, and source of extreme aerosol events, defined as when the concentration of a species on a particular day exceeds that of the average plus two standard deviations for that given month. Depending on which of eight sites studied, between 5% and 7% of the total days exhibited an extreme aerosol event due to either extreme levels of PM, PM, and/or fine soil. Grand Canyon exhibited the most extreme event days (120, , 7% of its total days). Read More

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January 2016

Windblown Dust Deposition Forecasting and Spread of Contamination around Mine Tailings.

Atmosphere (Basel) 2016 Feb 28;7(2). Epub 2016 Jan 28.

Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ 85721, USA.

Wind erosion, transport and deposition of windblown dust from anthropogenic sources, such as mine tailings impoundments, can have significant effects on the surrounding environment. The lack of vegetation and the vertical protrusion of the mine tailings above the neighboring terrain make the tailings susceptible to wind erosion. Modeling the erosion, transport and deposition of particulate matter from mine tailings is a challenge for many reasons, including heterogeneity of the soil surface, vegetative canopy coverage, dynamic meteorological conditions and topographic influences. Read More

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February 2016

Decreasing Aerosol Loading in the North American Monsoon Region.

Atmosphere (Basel) 2016 Feb 5;7(2). Epub 2016 Feb 5.

Department of Hydrology and Atmospheric Sciences, Tucson, AZ 85721, USA.

We examine the spatio-temporal variability of aerosol loading in the recent decade (2005-2014) over the North American Monsoon (NAM) region. Emerging patterns are characterized using aerosol optical depth (AOD) retrievals from the NASA Terra/Moderate Resolution Imaging Spectroradiometer (MODIS) instrument along with a suite of satellite retrievals of atmospheric and land-surface properties. We selected 20 aerosol hotspots and classified them into fire, anthropogenic, dust, and NAM alley clusters based on the dominant driver influencing aerosol variability. Read More

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February 2016

A Multi-Year Aerosol Characterization for the Greater Tehran Area Using Satellite, Surface, and Modeling Data.

Atmosphere (Basel) 2014 Apr;5(2):178-197

Department of Civil & Environmental Engineering, University of California, Irvine, Irvine, CA 92697, USA.

This study reports a multi-year (2000-2009) aerosol characterization for metropolitan Tehran and surrounding areas using multiple datasets (Moderate Resolution Imaging Spectroradiometer (MODIS), Multi-angle Imaging Spectroradiometer (MISR), Total Ozone Mapping Spectrometer (TOMS), Goddard Ozone Chemistry Aerosol Radiation and Transport (GOCART), and surface and upper air data from local stations). Monthly trends in aerosol characteristics are examined in the context of the local meteorology, regional and local emission sources, and air mass back-trajectory data. Dust strongly affects the region during the late spring and summer months (May-August) when aerosol optical depth (AOD) is at its peak and precipitation accumulation is at a minimum. Read More

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Emission Ratios for Ammonia and Formic Acid and Observations of Peroxy Acetyl Nitrate (PAN) and Ethylene in Biomass Burning Smoke as Seen by the Tropospheric Emission Spectrometer (TES).

Atmosphere (Basel) 2011 Dec 9;2(4):633-654. Epub 2011 Nov 9.

Atmospheric and Environmental Research (AER), Lexington, MA 02421, USA.

We use the Tropospheric Emission Spectrometer (TES) aboard the NASA Aura satellite to determine the concentrations of the trace gases ammonia (NH) and formic acid (HCOOH) within boreal biomass burning plumes, and present the first detection of peroxy acetyl nitrate (PAN) and ethylene (CH) by TES. We focus on two fresh Canadian plumes observed by TES in the summer of 2008 as part of the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS-B) campaign. We use TES retrievals of NH and HCOOH within the smoke plumes to calculate their emission ratios (1. Read More

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December 2011