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Natural and transboundary pollution influences on sulfate‐nitrate‐ammonium aerosols in the United States: Implications for policy
[1] We use a global three-dimensional coupled oxidant-aerosol model (GEOS-CHEM) to estimate natural and transboundary pollution influences on sulfate-nitrate-ammonium aerosol concentrations in theExpand
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A Large Organic Aerosol Source in the Free Troposphere Missing from Current Models
average 4 m gs m 3 in the 2–6.5 km column with little vertical gradient. These values are 10–100 times higher than computed with a global chemical transport model (CTM) including a standard 2-productExpand
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Chemical cycling and deposition of atmospheric mercury : Global constraints from observations
[1] We use a global 3-D model of atmospheric mercury (GEOS-Chem) to interpret worldwide observations of total gaseous mercury (TGM) and reactive gaseous mercury (RGM) in terms of the constraints theyExpand
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The impact of transpacific transport of mineral dust in the United States
Abstract We use a global chemical transport model (GEOS-Chem) to estimate the impact of transpacific transport of mineral dust on aerosol concentrations in North America during 2001. We haveExpand
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Mapping annual mean ground‐level PM2.5 concentrations using Multiangle Imaging Spectroradiometer aerosol optical thickness over the contiguous United States
[1] We present a simple approach to estimating ground-level fine particulate matter (PM2.5, particles smaller than 2.5 mm in diameter) concentrations by applying local scaling factors from a globalExpand
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Sources of carbonaceous aerosols over the United States and implications for natural visibility
emissions, captures most of the variance in the observations (R 2 = 0.84 for EC, 0.67 for OC) with a low bias of 15% for EC and 26% for OC. Multiple linear regression to fit the IMPROVE data yieldsExpand
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Transpacific Transport of Asian Anthropogenic Aerosols and its Impact on Surface Air Quality in the United States
[1] We use satellite (MODIS) observations of aerosol optical depths (AODs) over the North Pacific, together with surface aerosol measurements at a network of remote U.S. sites (IMPROVE), to improveExpand
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Modeling of gas and aerosol with WRF/Chem over Europe: Evaluation and sensitivity study
shows mean bias of about � 4.0 mg/m 3 (� 7.3%), mainly attributable to the carbonaceous fraction. The model underpredicts particulate sulphate by a factor of 2, and overpredicts ammonium and nitrateExpand
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Regional Visibility Statistics in the United States: Natural and Transboundary Pollution Influences, and Implications for the Regional Haze Rule
The Regional Haze Rule of the US Environmental Protection Agency mandates reduction in US anthropogenic emissions to achieve linear improvement of visibility in wilderness areas over the 2004–18Expand
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Observations of reactive gaseous mercury in the free troposphere at the Mount Bachelor Observatory
August 2005. The mean mercury concentrations (at standard conditions) were 1.54 ng/m 3 (GEM), 5.2 pg/m 3 (PHg), and 43 pg/m 3 (RGM). RGM enhancements, up to 600 pg/m 3 , occurred at night and wereExpand
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