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Background: Environmental epidemiologists strive to conduct research that will lead to actions that improve public health outcomes. The risk assessment process is the bridge between scientific research and policies that can impact public health. Historically, epidemiologic studie...

Epidemiologic studies of ambient fine particulate matter (PM2.5) and ozone (O3) often use outdoor concentrations from central-site monitors or air quality model estimates as exposure surrogates, which can result in exposure errors. We previously developed an exposure model called...

The importance of nitrate radicals (NO3) as anatmospheric oxidant is well-established. For decades, laboratorystudies of multiphase NO3 chemistry have used the same methods− either NO2 + O3 reactions or N2O5 thermal decomposition − togenerate NO3 as it occurs in the a...

Numerical simulation studies of the dispersion of dimethyl sulfide (DMS) in the air have increased over the last two decades in parallel with the interest in understanding its role as a precursor of non-sea salt aerosols in the lower to middle levels of the troposphere. Here, we ...

We implement particulate nitrate (pNO3-) photolysis into the Community Multiscale Air Quality (CMAQv5.5) model and examine the impact of pNO3- photolysis on air quality over the contiguous U.S. using 12-km horizontal grids for May-September 2018. Model results show that pNO3- pho...

This paper compared simulation results from different model constructions of a Storm Water Management Model (SWMM) after radiological contamination from a hypothetical dirty bomb scenario. The model constructions included a utility-provided combined sewer stormwater model, a high...

Social cohesion can reduce stress, increase social interaction, and improve cognitive reserve. These social mechanisms may modify the effects of air pollution on dementia risk. This cohort study examines the potential moderating effect of social cohesion on associations between j...

Formaldehyde (HCHO) is an important air pollutant with direct cancer risk and ozone-forming potential. HCHO sources are complex because HCHO is both directly emitted and produced from oxidation of most gas-phase reactive organic carbon. We update the secondary production of HCHO ...

The R-LINE model, which was released in 2013 as a stand-alone model for roadway-type applications and was based on a set of newly developed dispersion curves, exhibited favorable model performance in a limited set of evaluations. In 2019, the R-LINE model was incorporated as the ...

The presence of volatile organic compounds (VOCs) can increase the air pollution burden in fenceline communities. Technological advancements in instrumentation and methodologies have made mobile air toxics monitoring a high-resolution, portable, and adaptable approach to quantify...

Subsurface contamination can migrate upward into overlying buildings, exposing the buildings’ inhabitants to contaminants that can cause detrimental health effects. This phenomenon is known as vapor intrusion (VI). When evaluating a building for VI, one must understand that...

Per- and polyfluoroalkyl substances (PFAS) migrate into the environment through various means, e.g., soil-amendment impurities and ambient atmospheric deposition, potentially resulting in vegetative uptake and migration to groundwater. Existing approaches for modeling sorption of...

The resuspension of radioactively contaminated particles in a built environment, such as from urban surfaces like foliage, building exteriors, and roadways, is described empirically by current plume and dosimetry models used for hazard assessment and long-term risk purposes. When...

From July 2019 until January 2021, six models of PM2.5 air sensors were operated collocated at seven air quality monitoring sites across the United States in Arizona, Colorado, Delaware, Georgia, North Carolina, Oklahoma, and Wisconsin. Air sensors suffered from common failure po...

Despite decades of emission control measuresaimed at improving air quality, Los Angeles (LA) continues toexperience severe ozone pollution during the summertime. Weincorporate cooking volatile organic compound (VOC) emissionsin a chemical transport model and evaluate it against o...

A portion of Alaska’s Fairbanks North Star Borough was designated as nonattainment for the 2006 24 h fine particulate matter 2.5 µm or less in diameter (PM2.5) National Ambient Air Quality Standards (NAAQS) in 2009. PM2.5 NAAQS exceedances in Fairbanks mainly occur du...

Pellet-fueled cookstoves are a potentially valuable technology for people lacking access to gas or electric energy sources. This study examines three representative semi-gasifier cookstove models each burning four types of pelletized-biomass fuel (hardwood, peanut hull, risk husk...

Near-transportation source environments can be impacted by higher concentrations of particulate matter (PM) and other pollutants. Populations living in these environments may experience adverse health effects including cardiovascular and respiratory incidences. While there are ma...

Lagrangian tracer simulations are deployed to investigate processes influencing vertical and horizontal dispersion of anthropogenic pollution in Fairbanks, Alaska, during the Alaskan Layered Pollution and Chemical Analysis (ALPACA) 2022 field campaign. Simulated concentrations of...

This study investigated the effect of relative humidity (RH) on the chemical composition of gas and particle phases formed from the photooxidation of 1,3-butadiene (13BD) in the presence of NOx under acidified andnon-acidified seed aerosol. The experiments were conducted in a 14....

Exceedances of critical loads for deposition of sulphur and nitrogen to different ecosystems were estimated using European and North American ensembles of air quality models, under Phase 4 of the Air Quality Model Evaluation International Initiative (AQMEII4), to identify where r...

The spatiotemporal variations of fine particulate matter (PM2.5) chemical composition have changed over time in the U.S. and increasing evidence indicated differential toxicity of PM2.5 chemical composition. Thus, comprehensive explanation of PM2.5-related adverse ...

In the early days of the Coronavirus Disease 2019 (COVID-19) pandemic, the virus was spreading rapidly, the main routes of transmission were uncertain, little was known about how to attenuate its spread, and mortality rates were climbing. The U.S. EPA’s Office of Research and Dev...

Electrifying on-road trucking is a strategy for decarbonizing the transportation sector. While battery-electric trucks have zero tailpipe emissions, the associated increase in electric sector grid emissions would offset a portion of on-road emission reductions. We utilize a techn...

 Chlorine radicals (Cl) play a crucial role in atmospheric chemistry. The COVID-19 (coronavirus disease 2019) pandemic significantly increased the use of chlorine containing disinfectants in China, leading to enhanced emissions of chlorine gas (Cl2) and hypochlorous acid (HO...