Publications by authors named "Melanie S Hammer"

Prescribed fires (fires intentionally set for mitigation purposes) produce pollutants, which have negative effects on human and animal health. One of the pollutants produced from fires is fine particulate matter (PM). The Flint Hills (FH) region of Kansas experiences extensive prescribed burning each spring (March-May).

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Ambient fine particulate matter (PM) is the world's leading environmental health risk factor. Quantification is needed of regional contributions to changes in global PM exposure. Here we interpret satellite-derived PM estimates over 1998-2019 and find a reversal of previous growth in global PM air pollution, which is quantitatively attributed to contributions from 13 regions.

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Article Synopsis
  • Fine particulate matter (PM) is a major cause of premature deaths in South Asia, with approximately 1.02 million deaths linked to PM exposure in 2019.
  • The main contributors to PM-related mortality are residential combustion (28%), industry (15%), and power generation (12%), with solid biofuels being the largest fuel source (31%).
  • The study highlights the significant health benefits that could result from reducing emissions from traditional energy sources, particularly in high PM states like Delhi and Uttar-Pradesh.
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Low haemoglobin (Hb) concentrations and anaemia in children have adverse effects on development and functioning, some of which may have consequences in later life. Exposure to ambient air pollution is reported to be associated with anaemia, but there is little evidence specific to low- and middle-income countries (LMICs), where childhood anaemia prevalence is greatest. We aimed to determine if long-term ambient fine particulate matter (≤2.

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Exposure to ambient air pollution may affect cognitive functioning and development in children. Unfortunately, there is little evidence available for low- and middle-income countries (LMICs), where air pollution levels are highest. We analysed the association between exposure to ambient fine particulate matter (≤2.

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We investigate socioeconomic disparities in air quality at public schools in the contiguous US using high resolution estimates of fine particulate matter (PM) and nitrogen dioxide (NO) concentrations. We find that schools with higher proportions of people of color (POC) and students eligible for the federal free or reduced lunch program, a proxy for poverty level, are associated with higher pollutant concentrations. For example, we find that the median annual NO concentration for White students, nationally, was 7.

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Studies examining long-term effects of ambient air pollution exposure, measured as annual averages, on pulmonary tuberculosis (TB) incidence are scarce, particularly in endemic, rural settings. We performed a small-area study in Ningxia Hui Autonomous Region (NHAR), a high TB-burden area in rural China, using township-level (n = 358 non-overlapping townships) annual TB notification data (2005-2017). We aimed to determine if annual average concentrations of ambient air pollution (particulate matter <2·5 μm [PM], nitrogen dioxide [NO] ozone [O]) were associated with TB notification rates (as a proxy for incidence).

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Nitrogen dioxide (NO) is an important contributor to air pollution and can adversely affect human health. A decrease in NO concentrations has been reported as a result of lockdown measures to reduce the spread of COVID-19. Questions remain, however, regarding the relationship of satellite-derived atmospheric column NO data with health-relevant ambient ground-level concentrations, and the representativeness of limited ground-based monitoring data for global assessment.

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Background: With much of the world's population residing in urban areas, an understanding of air pollution exposures at the city level can inform mitigation approaches. Previous studies of global urban air pollution have not considered trends in air pollutant concentrations nor corresponding attributable mortality burdens. We aimed to estimate trends in fine particulate matter (PM) concentrations and associated mortality for cities globally.

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Background: Fine particulate matter (PM) exposure has been reported to adversely affect birth outcomes, but the evidence is limited, particularly in low- and middle-income countries (LMICs). We assessed the associations between maternal PM exposure and low birth weight (LBW) and preterm birth (PTB) in Africa.

Methods: We used standard Demographic and Health Surveys (DHS) data (2005-2015) from 15 countries in Africa to conduct a cross-sectional study.

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Background: Evidence from developed countries suggests that fine particulate matter (≤2.5 µm [PM]) contributes to childhood respiratory morbidity and mortality. However, few analyses have focused on resource-limited settings, where much of this burden occurs.

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Annual global satellite-based estimates of fine particulate matter (PM) are widely relied upon for air-quality assessment. Here, we develop and apply a methodology for monthly estimates and uncertainties during the period 1998-2019, which combines satellite retrievals of aerosol optical depth, chemical transport modeling, and ground-based measurements to allow for the characterization of seasonal and episodic exposure, as well as aid air-quality management. Many densely populated regions have their highest PM concentrations in winter, exceeding summertime concentrations by factors of 1.

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Emission regulations of the power and industry sectors have been identified as the major driver of PM mitigation over China during 2013-2017. In this study, we use ground-based observations of four air pollutants (CO, NO, SO, and PM) to show that additional stringent emission policies on the industrial, transportation, and residential sectors during the new 3-year protection plan (2018-2020) have accelerated the improvement of China's air quality. Based on regional (North and South China) trends of annual mean measurements, significant reductions are observed for all four pollutants during 2017-2020.

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Background: Few studies have investigated the association between exposure to fine particulate matter (PM) and infant mortality in developing countries, especially for the health effects of specific PM constituents.

Objective: We aimed to examine the association of long-term exposure to specific PM constituents with infant mortality in 15 African countries from 2005 to 2015.

Methods: Based on the Demographic and Health Surveys (DHS) dataset, we included birth history records from 15 countries in Africa and conducted a multicountry cross-sectional study to examine the associations between specific PM constituents and infant mortality.

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Lockdowns during the COVID-19 pandemic provide an unprecedented opportunity to examine the effects of human activity on air quality. The effects on fine particulate matter (PM) are of particular interest, as PM is the leading environmental risk factor for mortality globally. We map global PM concentrations for January to April 2020 with a focus on China, Europe, and North America using a combination of satellite data, simulation, and ground-based observations.

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Article Synopsis
  • Ambient fine particulate matter is the leading environmental health risk, with specific strategies needed to reduce its disease impact on a global scale.
  • The analysis evaluated contributions to PM-related health issues in 21 regions and found that eliminating fossil fuel use could have prevented over 1 million deaths in 2017, particularly from coal.
  • Other major sources included residential, industrial, and energy sectors, indicating significant health improvements could be achieved by shifting away from traditional energy sources.
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Exposure to outdoor fine particulate matter (PM) is a leading risk factor for mortality. We develop global estimates of annual PM concentrations and trends for 1998-2018 using advances in satellite observations, chemical transport modeling, and ground-based monitoring. Aerosol optical depths (AODs) from advanced satellite products including finer resolution, increased global coverage, and improved long-term stability are combined and related to surface PM concentrations using geophysical relationships between surface PM and AOD simulated by the GEOS-Chem chemical transport model with updated algorithms.

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We interpret in situ and satellite observations with a chemical transport model (GEOS-Chem, downscaled to 0.1° × 0.1°) to understand global trends in population-weighted mean chemical composition of fine particulate matter (PM).

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