Publications by authors named "Heather A Holmes"

Many current gridded surface meteorological datasets are inadequate for quantifying near-surface spatiotemporal variability because they do not fully represent the impacts of land surface heterogeneity. Of note, explicit representation of the spatial structure and magnitude of local urban warming are usually lacking. Here we enhance the representation of spatial meteorological variability over urban areas in the conterminous United States (CONUS) by employing the High-Resolution Land Data Assimilation System (HRLDAS), which accounts for the fine-scale impacts of spatiotemporally varying land surfaces on weather.

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  • Heat waves are becoming more common and intense, potentially impacting pregnancy outcomes such as preterm and early-term births.
  • A nationwide study analyzed over 53 million births in the U.S. from 1993 to 2017 to assess the effect of heat waves on birth rates, focusing on specific temperature data and timing related to births.
  • The results indicated that heat waves are linked to increased rates of both preterm and early-term births, especially when temperatures are extreme for four consecutive days, highlighting a concerning trend for maternal and infant health.
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Extreme heat events are occurring more frequently and with greater intensity due to climate change. They result in increased heat stress to populations causing human health impacts and heat-related deaths. The urban environment can also exacerbate heat stress because of man-made materials and increased population density.

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  • * It highlights the lack of validation datasets for these inventories and utilizes satellite data for fire radiative power to evaluate their accuracy.
  • * Findings suggest FINN and GFED may underestimate emissions, while MFLEI could overestimate them; none perfectly match the external data's emission timing, and the paper discusses the differences and methodologies behind the inventories.
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  • Accelerated urbanization leads to more frequent and intense heatwaves (HW) and urban heat islands (UHIs), as demonstrated by a significant HW event in summer 2012, where temperatures in Chicago exceeded 40°C.
  • A study used advanced numerical models like HRLDAS and WRF to simulate and evaluate the impacts of HW and UHI, finding that incorporating a multi-layer urban canopy model improved WRF's performance.
  • The analysis revealed that rural areas saw larger temperature increases (∼4°C) compared to urban Chicago (∼2-3°C), and strong nighttime UHI effects were noted, suggesting high heat stress risk in both urban and rural areas during heat events.
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Air pollutant accumulations during wintertime persistent cold air pool (PCAP) events in mountain valleys are of great concern for public health worldwide. Uncertainties associated with the simulated meteorology under stable conditions over complex terrain hinder realistic simulations of air quality using chemical transport models. We use the Community Multiscale Air Quality (CMAQ) model to simulate the gaseous and particulate species for 1 month in January 2011 during the Persistent Cold Air Pool Study (PCAPS) in the Salt Lake Valley (SLV), Utah (USA).

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Wintertime episodes of high aerosol concentrations occur frequently in urban and agricultural basins and valleys worldwide. These episodes often arise following development of persistent cold-air pools (PCAPs) that limit mixing and modify chemistry. While field campaigns targeting either basin meteorology or wintertime pollution chemistry have been conducted, coupling between interconnected chemical and meteorological processes remains an insufficiently studied research area.

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Background: The effect of heatwaves on adverse birth outcomes is not well understood and may vary by how heatwaves are defined. The study aims to examine acute associations between various heatwave definitions and preterm and early-term birth.

Methods: Using national vital records from 50 metropolitan statistical areas (MSAs) between 1982 and 1988, singleton preterm (< 37 weeks) and early-term births (37-38 weeks) were matched (1:1) to controls who completed at least 37 weeks or 39 weeks of gestation, respectively.

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  • A hybrid chemical transport model and receptor model (CTM-RM) was developed to analyze the impact of various sources of particulate matter (PM) on pediatric respiratory diseases in Georgia during 2005 and 2007.
  • The study focused on 12 specific PM sources, linking short-term changes in PM concentrations to emergency department visits among children with asthma, pneumonia, and acute upper respiratory infections.
  • Findings indicated positive associations between certain PM sources—particularly dust, metals, and natural gas—and increases in ED visits for respiratory conditions, emphasizing the health impacts of these pollutants.
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Ambient fine particulate matter less than 2.5 μm in aerodynamic diameter (PM) has been linked to various adverse health outcomes. PM arises from both natural and anthropogenic sources, and PM concentrations can vary over space and time.

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Motor vehicles are major sources of fine particulate matter (PM), and the PM from mobile vehicles is associated with adverse health effects. Traditional methods for estimating source impacts that employ receptor models are limited by the availability of observational data. To better estimate temporally and spatially resolved mobile source impacts on PM, we developed an approach based on a method that uses elemental carbon (EC), carbon monoxide (CO), and nitrogen oxide (NO) measurements as an indicator of mobile source impacts.

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The use of solid biomass fuels in cookstoves has been associated with chronic health impacts that disproportionately affect women worldwide. Solid fuel stoves that use wood, plant matter, and cow dung are commonly used for household cooking in rural Bangladesh. This study investigates the immediate effects of acute elevated cookstove emission exposures on pulmonary function.

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The spatial distribution of chemical compounds and concentration of reactive mercury (RM), defined as the sum of gaseous oxidized mercury (GOM) and <3 μm particulate bound mercury (PBM), are poorly characterized. The objective of this study was to understand the chemistry, concentration, and spatial and temporal distribution of GOM at adjacent locations (12 km apart) with a difference in elevation of ∼1000 m. Atmospheric GOM measurements were made with passive and active samplers using membranes, and at one location, a Tekran mercury measurement system was used.

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Investigations of ambient air pollution health effects rely on complete and accurate spatiotemporal air pollutant estimates. Three methods are developed for fusing ambient monitor measurements and 12 km resolution chemical transport model (CMAQ) simulations to estimate daily air pollutant concentrations across Georgia. Temporal variance is determined by observations in one method, with the annual mean CMAQ field providing spatial structure.

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Background: Previous epidemiologic studies suggest associations between preterm birth and ambient air pollution.

Objective: We investigated associations between 11 ambient air pollutants, estimated by combining Community Multiscale Air Quality model (CMAQ) simulations with measurements from stationary monitors, and risk of preterm birth (< 37 weeks of gestation) in the U.S.

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Cold air pools (CAPs) are stagnant stable air masses that form in valleys and basins in the winter. Low wintertime insolation limits convective mixing, such that pollutant concentrations can build up within the CAP when pollutant sources are present. In the western United States, wintertime CAPs often persist for days or weeks.

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This paper reports findings from a case study designed to investigate indoor and outdoor air quality in homes near the United States-Mexico border During the field study, size-resolved continuous particulate matter (PM) concentrations were measured in six homes, while outdoor PM was simultaneously monitored at the same location in Nogales, Sonora, Mexico, during March 14-30, 2009. The purpose of the experiment was to compare PM in homes using different fuels for cooking, gas versus biomass, and to obtain a spatial distribution of outdoor PM in a region where local sources vary significantly (e.g.

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A Bayesian source apportionment (SA) method is developed to provide source impact estimates and associated uncertainties. Bayesian-based ensemble averaging of multiple models provides new source profiles for use in a chemical mass balance (CMB) SA of fine particulate matter (PM2.5).

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