The Experts below are selected from a list of 1890 Experts worldwide ranked by ideXlab platform
Rokjin J Park - One of the best experts on this subject based on the ideXlab platform.
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regional visibility statistics in the united states natural and Transboundary Pollution influences and implications for the regional haze rule
Atmospheric Environment, 2006Co-Authors: Rokjin J Park, Daniel J Jacob, Naresh Kumar, Robert M YantoscaAbstract: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 2004–18 period toward an endpoint of natural visibility conditions by 2064. Linear improvement is to apply to the mean visibility degradation on the statistically 20% worst days, measured as a Haze Index in units of deciviews (log of aerosol extinction). We use a global chemical transport model (GEOS-Chem) with 11 � 11 horizontal resolution to simulate present-day visibility statistics in the USA, compare them to observations from the Interagency Monitoring of Protected Visual Environments (IMPROVE) surface network, and provide natural and background visibility statistics for application of the Regional Haze Rule. Background is defined by suppression of US anthropogenic emissions but allowance for present-day foreign emissions and associated import of Pollution. Our model is highly successful at reproducing the observed variability of visibility statistics for present-day conditions, including the low tail of the frequency distribution that is most representative of natural or background conditions. We find considerable spatial and temporal variability in natural visibility over the USA, especially due to fires in the west. A major uncertainty in estimating natural visibility is the sensitivity of biogenic organic aerosol formation to the availability of preexisting anthropogenic aerosol. Background visibility is more variable than natural visibility and the 20% worst days show large contributions from Canadian and Mexican Pollution. Asian Pollution, while degrading mean background visibility, is relatively less important on the worst days. Recognizing the influence of uncontrollable Transboundary Pollution in the Regional Haze Rule would substantially decrease the schedule of emission reductions required in the 2004–18 implementation phase. Meaningful application of the Rule in the future will require projections of future trends in foreign anthropogenic emissions, wildfire frequency, and climate variables. r 2006 Elsevier Ltd. All rights reserved.
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natural and Transboundary Pollution influences on sulfate nitrate ammonium aerosols in the united states implications for policy
Journal of Geophysical Research, 2004Co-Authors: Rokjin J Park, Daniel J Jacob, Brendan D Field, Robert M Yantosca, Mian ChinAbstract:[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 the United States. This work is motivated in part by the Regional Haze Rule of the U.S. Environmental Protection Agency (EPA), which requires immediate action to improve visibility in U.S. wilderness areas along a linear trajectory toward an endpoint of “natural visibility conditions” by 2064. We present full-year simulations for 1998 and 2001 and evaluate them with nationwide networks of observations in the United States and Europe (Interagency Monitoring of Protected Visual Environments (IMPROVE), Clean Air Status and Trends Network (CASTNET), National Atmospheric Deposition Program (NADP), European Monitoring and Evaluation Programme (EMEP)) and with Asian outflow observations from the NASA Transport and Chemical Evolution over the Pacific (TRACE-P) aircraft mission. Shutting off U.S. anthropogenic emissions in the model defines “background” aerosol concentrations representing contributions from both natural and Transboundary Pollution sources. We find that Transboundary transport of Pollution from Canada, Mexico, and Asia dominates over natural influences for both sulfate and nitrate. Trans-Pacific transport of Asian Pollution accounts for 30% of background sulfate in both the western and eastern United States. Our best estimates of natural concentrations for ammonium sulfate and ammonium nitrate in the United States are either consistent with or lower than the default values recommended by EPA for natural visibility calculations. However, the large Transboundary Pollution influence in our calculation suggests that a natural visibility objective cannot be approached without international emission controls.
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Natural and Transboundary Pollution influences on sulfate‐nitrate‐ammonium aerosols in the United States: Implications for policy
Journal of Geophysical Research, 2004Co-Authors: Rokjin J Park, Daniel J Jacob, Brendan D Field, Robert M Yantosca, Mian ChinAbstract:[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 the United States. This work is motivated in part by the Regional Haze Rule of the U.S. Environmental Protection Agency (EPA), which requires immediate action to improve visibility in U.S. wilderness areas along a linear trajectory toward an endpoint of “natural visibility conditions” by 2064. We present full-year simulations for 1998 and 2001 and evaluate them with nationwide networks of observations in the United States and Europe (Interagency Monitoring of Protected Visual Environments (IMPROVE), Clean Air Status and Trends Network (CASTNET), National Atmospheric Deposition Program (NADP), European Monitoring and Evaluation Programme (EMEP)) and with Asian outflow observations from the NASA Transport and Chemical Evolution over the Pacific (TRACE-P) aircraft mission. Shutting off U.S. anthropogenic emissions in the model defines “background” aerosol concentrations representing contributions from both natural and Transboundary Pollution sources. We find that Transboundary transport of Pollution from Canada, Mexico, and Asia dominates over natural influences for both sulfate and nitrate. Trans-Pacific transport of Asian Pollution accounts for 30% of background sulfate in both the western and eastern United States. Our best estimates of natural concentrations for ammonium sulfate and ammonium nitrate in the United States are either consistent with or lower than the default values recommended by EPA for natural visibility calculations. However, the large Transboundary Pollution influence in our calculation suggests that a natural visibility objective cannot be approached without international emission controls.
Mian Chin - One of the best experts on this subject based on the ideXlab platform.
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natural and Transboundary Pollution influences on sulfate nitrate ammonium aerosols in the united states implications for policy
Journal of Geophysical Research, 2004Co-Authors: Rokjin J Park, Daniel J Jacob, Brendan D Field, Robert M Yantosca, Mian ChinAbstract:[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 the United States. This work is motivated in part by the Regional Haze Rule of the U.S. Environmental Protection Agency (EPA), which requires immediate action to improve visibility in U.S. wilderness areas along a linear trajectory toward an endpoint of “natural visibility conditions” by 2064. We present full-year simulations for 1998 and 2001 and evaluate them with nationwide networks of observations in the United States and Europe (Interagency Monitoring of Protected Visual Environments (IMPROVE), Clean Air Status and Trends Network (CASTNET), National Atmospheric Deposition Program (NADP), European Monitoring and Evaluation Programme (EMEP)) and with Asian outflow observations from the NASA Transport and Chemical Evolution over the Pacific (TRACE-P) aircraft mission. Shutting off U.S. anthropogenic emissions in the model defines “background” aerosol concentrations representing contributions from both natural and Transboundary Pollution sources. We find that Transboundary transport of Pollution from Canada, Mexico, and Asia dominates over natural influences for both sulfate and nitrate. Trans-Pacific transport of Asian Pollution accounts for 30% of background sulfate in both the western and eastern United States. Our best estimates of natural concentrations for ammonium sulfate and ammonium nitrate in the United States are either consistent with or lower than the default values recommended by EPA for natural visibility calculations. However, the large Transboundary Pollution influence in our calculation suggests that a natural visibility objective cannot be approached without international emission controls.
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Natural and Transboundary Pollution influences on sulfate‐nitrate‐ammonium aerosols in the United States: Implications for policy
Journal of Geophysical Research, 2004Co-Authors: Rokjin J Park, Daniel J Jacob, Brendan D Field, Robert M Yantosca, Mian ChinAbstract:[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 the United States. This work is motivated in part by the Regional Haze Rule of the U.S. Environmental Protection Agency (EPA), which requires immediate action to improve visibility in U.S. wilderness areas along a linear trajectory toward an endpoint of “natural visibility conditions” by 2064. We present full-year simulations for 1998 and 2001 and evaluate them with nationwide networks of observations in the United States and Europe (Interagency Monitoring of Protected Visual Environments (IMPROVE), Clean Air Status and Trends Network (CASTNET), National Atmospheric Deposition Program (NADP), European Monitoring and Evaluation Programme (EMEP)) and with Asian outflow observations from the NASA Transport and Chemical Evolution over the Pacific (TRACE-P) aircraft mission. Shutting off U.S. anthropogenic emissions in the model defines “background” aerosol concentrations representing contributions from both natural and Transboundary Pollution sources. We find that Transboundary transport of Pollution from Canada, Mexico, and Asia dominates over natural influences for both sulfate and nitrate. Trans-Pacific transport of Asian Pollution accounts for 30% of background sulfate in both the western and eastern United States. Our best estimates of natural concentrations for ammonium sulfate and ammonium nitrate in the United States are either consistent with or lower than the default values recommended by EPA for natural visibility calculations. However, the large Transboundary Pollution influence in our calculation suggests that a natural visibility objective cannot be approached without international emission controls.
Robert M Yantosca - One of the best experts on this subject based on the ideXlab platform.
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regional visibility statistics in the united states natural and Transboundary Pollution influences and implications for the regional haze rule
Atmospheric Environment, 2006Co-Authors: Rokjin J Park, Daniel J Jacob, Naresh Kumar, Robert M YantoscaAbstract: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 2004–18 period toward an endpoint of natural visibility conditions by 2064. Linear improvement is to apply to the mean visibility degradation on the statistically 20% worst days, measured as a Haze Index in units of deciviews (log of aerosol extinction). We use a global chemical transport model (GEOS-Chem) with 11 � 11 horizontal resolution to simulate present-day visibility statistics in the USA, compare them to observations from the Interagency Monitoring of Protected Visual Environments (IMPROVE) surface network, and provide natural and background visibility statistics for application of the Regional Haze Rule. Background is defined by suppression of US anthropogenic emissions but allowance for present-day foreign emissions and associated import of Pollution. Our model is highly successful at reproducing the observed variability of visibility statistics for present-day conditions, including the low tail of the frequency distribution that is most representative of natural or background conditions. We find considerable spatial and temporal variability in natural visibility over the USA, especially due to fires in the west. A major uncertainty in estimating natural visibility is the sensitivity of biogenic organic aerosol formation to the availability of preexisting anthropogenic aerosol. Background visibility is more variable than natural visibility and the 20% worst days show large contributions from Canadian and Mexican Pollution. Asian Pollution, while degrading mean background visibility, is relatively less important on the worst days. Recognizing the influence of uncontrollable Transboundary Pollution in the Regional Haze Rule would substantially decrease the schedule of emission reductions required in the 2004–18 implementation phase. Meaningful application of the Rule in the future will require projections of future trends in foreign anthropogenic emissions, wildfire frequency, and climate variables. r 2006 Elsevier Ltd. All rights reserved.
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natural and Transboundary Pollution influences on sulfate nitrate ammonium aerosols in the united states implications for policy
Journal of Geophysical Research, 2004Co-Authors: Rokjin J Park, Daniel J Jacob, Brendan D Field, Robert M Yantosca, Mian ChinAbstract:[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 the United States. This work is motivated in part by the Regional Haze Rule of the U.S. Environmental Protection Agency (EPA), which requires immediate action to improve visibility in U.S. wilderness areas along a linear trajectory toward an endpoint of “natural visibility conditions” by 2064. We present full-year simulations for 1998 and 2001 and evaluate them with nationwide networks of observations in the United States and Europe (Interagency Monitoring of Protected Visual Environments (IMPROVE), Clean Air Status and Trends Network (CASTNET), National Atmospheric Deposition Program (NADP), European Monitoring and Evaluation Programme (EMEP)) and with Asian outflow observations from the NASA Transport and Chemical Evolution over the Pacific (TRACE-P) aircraft mission. Shutting off U.S. anthropogenic emissions in the model defines “background” aerosol concentrations representing contributions from both natural and Transboundary Pollution sources. We find that Transboundary transport of Pollution from Canada, Mexico, and Asia dominates over natural influences for both sulfate and nitrate. Trans-Pacific transport of Asian Pollution accounts for 30% of background sulfate in both the western and eastern United States. Our best estimates of natural concentrations for ammonium sulfate and ammonium nitrate in the United States are either consistent with or lower than the default values recommended by EPA for natural visibility calculations. However, the large Transboundary Pollution influence in our calculation suggests that a natural visibility objective cannot be approached without international emission controls.
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Natural and Transboundary Pollution influences on sulfate‐nitrate‐ammonium aerosols in the United States: Implications for policy
Journal of Geophysical Research, 2004Co-Authors: Rokjin J Park, Daniel J Jacob, Brendan D Field, Robert M Yantosca, Mian ChinAbstract:[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 the United States. This work is motivated in part by the Regional Haze Rule of the U.S. Environmental Protection Agency (EPA), which requires immediate action to improve visibility in U.S. wilderness areas along a linear trajectory toward an endpoint of “natural visibility conditions” by 2064. We present full-year simulations for 1998 and 2001 and evaluate them with nationwide networks of observations in the United States and Europe (Interagency Monitoring of Protected Visual Environments (IMPROVE), Clean Air Status and Trends Network (CASTNET), National Atmospheric Deposition Program (NADP), European Monitoring and Evaluation Programme (EMEP)) and with Asian outflow observations from the NASA Transport and Chemical Evolution over the Pacific (TRACE-P) aircraft mission. Shutting off U.S. anthropogenic emissions in the model defines “background” aerosol concentrations representing contributions from both natural and Transboundary Pollution sources. We find that Transboundary transport of Pollution from Canada, Mexico, and Asia dominates over natural influences for both sulfate and nitrate. Trans-Pacific transport of Asian Pollution accounts for 30% of background sulfate in both the western and eastern United States. Our best estimates of natural concentrations for ammonium sulfate and ammonium nitrate in the United States are either consistent with or lower than the default values recommended by EPA for natural visibility calculations. However, the large Transboundary Pollution influence in our calculation suggests that a natural visibility objective cannot be approached without international emission controls.
B. R. Copeland - One of the best experts on this subject based on the ideXlab platform.
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Trade and Transboundary Pollution
American Economic Review, 1995Co-Authors: B. R. Copeland, M.s. TaylorAbstract:This paper examines how national income and trading opportunities interact to determine the level and incidence of world Pollution. We find that (i) free trade raises world Pollution if incomes differ substantially across countries; (ii) if trade equalizes factor prices, human-capital-abundant countries lose from trade, while human-capital-scarce countries gain; (iii) international trade in Pollution permits can lower world Pollution even when governments' supply of permits is unrestricted; (iv) international income transfers may not affect world Pollution or welfare; and (v) attempts to manipulate the terms of trade with Pollution policy leave world Pollution unaffected.
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trade and Transboundary Pollution
The American Economic Review, 1995Co-Authors: B. R. Copeland, Scott M TaylorAbstract:This paper examines how national income and trading opportunities interact to determine the level and incidence of world Pollution. The authors find that free trade raises world Pollution if incomes differ substantially across countries; if trade equalizes factor prices, human-capital-abundant countries lose from trade, while human-capital-scarce countries gain; international trade in Pollution permits can lower world Pollution even when governments' supply of permits is unrestricted; international income transfers may not affect world Pollution or welfare; and attempts to manipulate the terms of trade with Pollution policy leave world Pollution unaffected. Copyright 1995 by American Economic Association.
Daniel J Jacob - One of the best experts on this subject based on the ideXlab platform.
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regional visibility statistics in the united states natural and Transboundary Pollution influences and implications for the regional haze rule
Atmospheric Environment, 2006Co-Authors: Rokjin J Park, Daniel J Jacob, Naresh Kumar, Robert M YantoscaAbstract: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 2004–18 period toward an endpoint of natural visibility conditions by 2064. Linear improvement is to apply to the mean visibility degradation on the statistically 20% worst days, measured as a Haze Index in units of deciviews (log of aerosol extinction). We use a global chemical transport model (GEOS-Chem) with 11 � 11 horizontal resolution to simulate present-day visibility statistics in the USA, compare them to observations from the Interagency Monitoring of Protected Visual Environments (IMPROVE) surface network, and provide natural and background visibility statistics for application of the Regional Haze Rule. Background is defined by suppression of US anthropogenic emissions but allowance for present-day foreign emissions and associated import of Pollution. Our model is highly successful at reproducing the observed variability of visibility statistics for present-day conditions, including the low tail of the frequency distribution that is most representative of natural or background conditions. We find considerable spatial and temporal variability in natural visibility over the USA, especially due to fires in the west. A major uncertainty in estimating natural visibility is the sensitivity of biogenic organic aerosol formation to the availability of preexisting anthropogenic aerosol. Background visibility is more variable than natural visibility and the 20% worst days show large contributions from Canadian and Mexican Pollution. Asian Pollution, while degrading mean background visibility, is relatively less important on the worst days. Recognizing the influence of uncontrollable Transboundary Pollution in the Regional Haze Rule would substantially decrease the schedule of emission reductions required in the 2004–18 implementation phase. Meaningful application of the Rule in the future will require projections of future trends in foreign anthropogenic emissions, wildfire frequency, and climate variables. r 2006 Elsevier Ltd. All rights reserved.
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natural and Transboundary Pollution influences on sulfate nitrate ammonium aerosols in the united states implications for policy
Journal of Geophysical Research, 2004Co-Authors: Rokjin J Park, Daniel J Jacob, Brendan D Field, Robert M Yantosca, Mian ChinAbstract:[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 the United States. This work is motivated in part by the Regional Haze Rule of the U.S. Environmental Protection Agency (EPA), which requires immediate action to improve visibility in U.S. wilderness areas along a linear trajectory toward an endpoint of “natural visibility conditions” by 2064. We present full-year simulations for 1998 and 2001 and evaluate them with nationwide networks of observations in the United States and Europe (Interagency Monitoring of Protected Visual Environments (IMPROVE), Clean Air Status and Trends Network (CASTNET), National Atmospheric Deposition Program (NADP), European Monitoring and Evaluation Programme (EMEP)) and with Asian outflow observations from the NASA Transport and Chemical Evolution over the Pacific (TRACE-P) aircraft mission. Shutting off U.S. anthropogenic emissions in the model defines “background” aerosol concentrations representing contributions from both natural and Transboundary Pollution sources. We find that Transboundary transport of Pollution from Canada, Mexico, and Asia dominates over natural influences for both sulfate and nitrate. Trans-Pacific transport of Asian Pollution accounts for 30% of background sulfate in both the western and eastern United States. Our best estimates of natural concentrations for ammonium sulfate and ammonium nitrate in the United States are either consistent with or lower than the default values recommended by EPA for natural visibility calculations. However, the large Transboundary Pollution influence in our calculation suggests that a natural visibility objective cannot be approached without international emission controls.
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Natural and Transboundary Pollution influences on sulfate‐nitrate‐ammonium aerosols in the United States: Implications for policy
Journal of Geophysical Research, 2004Co-Authors: Rokjin J Park, Daniel J Jacob, Brendan D Field, Robert M Yantosca, Mian ChinAbstract:[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 the United States. This work is motivated in part by the Regional Haze Rule of the U.S. Environmental Protection Agency (EPA), which requires immediate action to improve visibility in U.S. wilderness areas along a linear trajectory toward an endpoint of “natural visibility conditions” by 2064. We present full-year simulations for 1998 and 2001 and evaluate them with nationwide networks of observations in the United States and Europe (Interagency Monitoring of Protected Visual Environments (IMPROVE), Clean Air Status and Trends Network (CASTNET), National Atmospheric Deposition Program (NADP), European Monitoring and Evaluation Programme (EMEP)) and with Asian outflow observations from the NASA Transport and Chemical Evolution over the Pacific (TRACE-P) aircraft mission. Shutting off U.S. anthropogenic emissions in the model defines “background” aerosol concentrations representing contributions from both natural and Transboundary Pollution sources. We find that Transboundary transport of Pollution from Canada, Mexico, and Asia dominates over natural influences for both sulfate and nitrate. Trans-Pacific transport of Asian Pollution accounts for 30% of background sulfate in both the western and eastern United States. Our best estimates of natural concentrations for ammonium sulfate and ammonium nitrate in the United States are either consistent with or lower than the default values recommended by EPA for natural visibility calculations. However, the large Transboundary Pollution influence in our calculation suggests that a natural visibility objective cannot be approached without international emission controls.
