scholarly journals Incorporation of volcanic SO<sub>2</sub> emissions in the Hemispheric CMAQ (H-CMAQ) version 5.2 modeling system and assessing their impacts on sulfate aerosol over the Northern Hemisphere

2021 ◽  
Vol 14 (9) ◽  
pp. 5751-5768
Author(s):  
Syuichi Itahashi ◽  
Rohit Mathur ◽  
Christian Hogrefe ◽  
Sergey L. Napelenok ◽  
Yang Zhang
Keyword(s):  
United States ◽  
Air Quality ◽  
Northern Hemisphere ◽  
The United States ◽  
Sulfate Aerosol ◽  
Free Troposphere ◽  
So2 Emissions ◽  
Central Pacific ◽  
Model Simulations ◽  
Volcanic Source

Abstract. The state-of-the-science Community Multiscale Air Quality (CMAQ) Modeling System has recently been extended for hemispheric-scale modeling applications (referred to as H-CMAQ). In this study, satellite-constrained estimation of the degassing SO2 emissions from 50 volcanoes over the Northern Hemisphere is incorporated into H-CMAQ, and their impact on tropospheric sulfate aerosol (SO42-) levels is assessed for 2010. The volcanic degassing improves predictions of observations from the Acid Deposition Monitoring Network in East Asia (EANET), the United States Clean Air Status and Trends Network (CASTNET), and the United States Integrated Monitoring of Protected Visual Environments (IMPROVE). Over Asia, the increased SO42- concentrations were seen to correspond to the locations of volcanoes, especially over Japan and Indonesia. Over the USA, the largest impacts that occurred over the central Pacific were caused by including the Hawaiian Kilauea volcano, while the impacts on the continental USA were limited to the western portion during summertime. The emissions of the Soufrière Hills volcano located on the island of Montserrat in the Caribbean Sea affected the southeastern USA during the winter season. The analysis at specific sites in Hawaii and Florida also confirmed improvements in regional performance for modeled SO42- by including volcanoes SO2 emissions. At the edge of the western USA, monthly averaged SO42- enhancements greater than 0.1 µg m−3 were noted within the boundary layer (defined as surface to 750 hPa) during June–September. Investigating the change on SO42- concentration throughout the free troposphere revealed that although the considered volcanic SO2 emissions occurred at or below the middle of free troposphere (500 hPa), compared to the simulation without the volcanic source, SO42- enhancements of more than 10 % were detected up to the top of the free troposphere (250 hPa). Our model simulations and comparisons with measurements across the Northern Hemisphere indicate that the degassing volcanic SO2 emissions are an important source and should be considered in air quality model simulations assessing background SO42- levels and their source attribution.

scholarly journals Incorporation of volcanic SO<sub>2</sub> emissions in the Hemispheric CMAQ (H-CMAQ) version 5.2 modeling system and assessing their impacts on sulfate aerosol over Northern Hemisphere

2021 ◽  
Author(s):  
Syuichi Itahashi ◽  
Rohit Mathur ◽  
Christian Hogrefe ◽  
Sergey L. Napelenok ◽  
Yang Zhang
Keyword(s):  
United States ◽  
Air Quality ◽  
Northern Hemisphere ◽  
The United States ◽  
Sulfate Aerosol ◽  
Free Troposphere ◽  
So2 Emissions ◽  
Central Pacific ◽  
Model Simulations ◽  
Volcanic Source

Abstract. The state-of-the-science Community Multiscale Air Quality (CMAQ) Modeling System has recently been extended for hemispheric-scale modeling applications (referred to as H-CMAQ). In this study, satellite-constrained estimation of the degassing SO2 emissions from 50 volcanos over the northern hemisphere is incorporated into H-CMAQ, and their impact on tropospheric sulfate aerosol (SO42−) levels is assessed for 2010. The volcanic degassing improves predictions of observations from the Acid Deposition Monitoring Network in East Asia (EANET), the United States Clean Air Status and Trends Network (CASTNET), and the United States Integrated Monitoring of Protected Visual Environments (IMPROVE). Over Asia, the increased SO42− concentrations were seen to correspond to the locations of volcanoes, especially over Japan and Indonesia. Over the U.S.A., the largest impacts occurred over the central Pacific caused by including the Hawaiian Kilauea volcano while the impacts on the continental U.S.A. were limited to the western portion during summertime. The emissions of the Soufriere Hills volcano located on Montserrat Island in the Caribbean Ocean affected the southeastern U.S.A. during the winter season. The analysis at specific sites in Hawaii and Florida also confirmed improvements in regional performance for modeled SO42− by including volcanoes SO2 emissions. At the edge of the western U.S.A., monthly-averaged SO42− enhancements greater than 0.1 μg/m3 were noted within the boundary layer (defined as surface to 750 hPa) during June–September. Investigating the change on SO42− concentration throughout the free troposphere revealed that although the considered volcanic SO2 emissions occurred at or below the middle of free troposphere (500 hPa), compared to the simulation without the volcanic source, SO42− enhancements of more than 10 % were detected up to the top of the free troposphere (250 hPa). Our model simulations and comparisons with measurements across the Northern Hemisphere indicate that the degassing volcanic SO2 emissions are an important source impacting airborne sulfur budgets and should be considered in air quality model simulations assessing background SO42− levels and their source attribution.

scholarly journals Impact of northern hemisphere mid-latitude anthropogenic sulfur dioxide emissions on local and remote tropospheric oxidants

2021 ◽  
Author(s):  
Daniel M. Westervelt ◽  
Arlene M. Fiore ◽  
Colleen B. Baublitz ◽  
Gustavo Correa
Keyword(s):  
Sulfur Dioxide ◽  
Northern Hemisphere ◽  
Surface Ozone ◽  
Sulfate Aerosol ◽  
The Arctic ◽  
Free Troposphere ◽  
So2 Emissions ◽  
Photolysis Rates ◽  
The Us ◽  
The Future

Abstract. The unintended consequences of reductions in regional anthropogenic sulfur dioxide (SO2) emissions implemented to protect human health are poorly understood. SO2 decreases began in the 1970s in the US and Europe and are expected to continue into the future, while recent emissions decreases in China are also projected to continue. In addition to the well documented climate effects (warming) from reducing aerosols, tropospheric oxidation is impacted via aerosol modification of photolysis rates and radical sinks. Impacts on the hydroxyl radical and other trace constituents directly affect climate and air quality metrics such as surface ozone levels. We use the Geophysical Fluid Dynamics Laboratory Atmospheric Model version 3 nudged towards National Centers for Environmental Prediction (NCEP) reanalysis wind velocities to estimate the impact of SO2 emissions from the United States, Europe, and China by differencing a control simulation with an otherwise identical simulation in which 2015 anthropogenic SO2 emissions are set to zero over one of the regions. Springtime sulfate aerosol changes occur both locally to the emission region and also throughout the Northern Hemispheric troposphere, including remote oceanic regions and the Arctic. The presence of sulfate aerosol strongly reduces hydroxyl (OH) and hydroperoxy (HO2) radicals by up to 10 % year-round throughout most of the troposphere north of 30° N latitude, the latter of which is directly removed via heterogeneous chemistry on aerosol surfaces, including sulfate, in the model. Regional SO2 emissions significantly increase nitrogen oxides (NOx) by about 5–8 % throughout most of the free troposphere in the Northern hemisphere by increasing the NOx lifetime as the heterogeneous sink on sulfate aerosol declines. Despite the NOx increases, tropospheric ozone decreases at northern mid-latitudes by 1–4 % zonally averaged and by up to 5 ppbv in surface air over China, as its response is dominated by the larger decreases (up to 2x) in HO2 and OH. Since 2015 anthropogenic SO2 emissions in China exceed those in the US or Europe, the oxidative response is greatest for the China perturbation simulation. Chemical effects of aerosols on oxidation (reactive uptake) dominate over radiative effects (photolysis rates), the latter of which are only statistically significant locally for the large perturbation over China. We find that the emissions decrease in China, which has yet to be fully realized, will have the largest impact on oxidants and related species in the Northern Hemisphere free troposphere compared to changes in Europe or the USA. Our results bolster previous calls for a multipollutant strategy for air pollution mitigation, to avoid the unintended consequence of aerosol removal leading to surface ozone increases that offset or mask surface ozone gains achieved by regulation of other pollutants, especially in countries where current usage of high-sulfur emitting fuels may be phased out in the future.

scholarly journals Observations and modeling of air quality trends over 1990–2010 across the Northern Hemisphere: China, the United States and Europe

2014 ◽  
Vol 14 (18) ◽  
pp. 25453-25501 ◽  
Author(s):  
J. Xing ◽  
R. Mathur ◽  
J. Pleim ◽  
C. Hogrefe ◽  
C.-M. Gan ◽  
...  
Keyword(s):  
United States ◽  
Air Quality ◽  
Northern Hemisphere ◽  
Linear Response ◽  
Eastern China ◽  
The United States ◽  
Nox Emissions ◽  
Voc Emissions ◽  
The Past ◽  
The Us

Abstract. Trends in air quality across the Northern Hemisphere over a 21 year period (1990–2010) were simulated using the CMAQ multiscale chemical transport model driven by meteorology from WRF simulations and internally consistent historical emission inventories obtained from EDGAR. Thorough comparison with several ground observation networks mostly over Europe and North America was conducted to evaluate the model performance as well as the ability of CMAQ to reproduce the observed trends in air quality over the past two decades in three regions: eastern China, the continental United States and Europe. The model successfully reproduced the observed decreasing trends in SO2, NO2, maxima 8 h O3, SO42− and EC in the US and Europe. However, the model fails to reproduce the decreasing trends in NO3− in the US, potentially pointing to uncertainties of NH3 emissions. The model failed to capture the 6 year trends of SO2 and NO2 in CN-API from 2005–2010, but reproduced the observed pattern of O3 trends shown in three WDCGG sites over eastern Asia. Due to the coarse spatial resolution employed in these calculations, predicted SO2 and NO2 concentrations are underestimated relative to all urban networks, i.e., US-AQS (NMB = −46 and −54%), EU-AIRBASE (NMB = −12 and −57%) and CN-API (NMB = −36 and −68%). Conversely, at the rural network EU-EMEP SO2 is overestimated (NMB from 4 to 150%) while NO2 is simulated well (NMB within ±15%) in all seasons. Correlations between simulated and observed winter time daily maxima 8 h (DM8) O3 are poor compared to other seasons for all networks. Better correlation between simulated and observed SO42− was found compared to that for SO2. Underestimation of summer SO42− in the US may be associated with the uncertainty in precipitation and associated wet scavenging representation in the model. The model exhibits worse performance for NO3− predictions, particularly in summer, due to high uncertainties in the gas/particle partitioning of NO3− as well as seasonal variations of NH3 emissions. There are high correlations (R > 0.5) between observed and simulated EC, although the model underestimates the EC concentration by 65% due to the coarse grid resolution as well as uncertainties in the PM speciation profile associated with EC emissions. The almost linear response seen in the trajectory of modeled O3 changes in the eastern China over the past two decades, suggests that control strategies that focus on combined control of NOx and VOC emissions with a ratio of 0.46 may provide the most effective means for O3 reductions for the region devoid of non-linear response potentially associated with NOx or VOC limitation resulting from alternate strategies. The response of O3 is more sensitive to changes in NOx emissions in the eastern US because the relative abundance of biogenic VOC emissions tends to reduce the effectiveness of VOC controls. Increasing NH3 levels offset the relative effectiveness of NOx controls in reducing the relative fraction of aerosol NO3− formed from declining NOx emissions in the eastern US, while the control effectiveness was assured by the simultaneous control of NH3 emission in Europe.

scholarly journals Observations and modeling of air quality trends over 1990–2010 across the Northern Hemisphere: China, the United States and Europe

2015 ◽  
Vol 15 (5) ◽  
pp. 2723-2747 ◽  
Author(s):  
J. Xing ◽  
R. Mathur ◽  
J. Pleim ◽  
C. Hogrefe ◽  
C.-M. Gan ◽  
...  
Keyword(s):  
United States ◽  
Air Quality ◽  
Northern Hemisphere ◽  
Eastern China ◽  
The United States ◽  
Quality Data ◽  
Nox Emissions ◽  
Voc Emissions ◽  
The Past ◽  
The Us

Abstract. Trends in air quality across the Northern Hemisphere over a 21-year period (1990–2010) were simulated using the Community Multiscale Air Quality (CMAQ) multiscale chemical transport model driven by meteorology from Weather Research and Forecasting (WRF) simulations and internally consistent historical emission inventories obtained from EDGAR. Thorough comparison with several ground observation networks mostly over Europe and North America was conducted to evaluate the model performance as well as the ability of CMAQ to reproduce the observed trends in air quality over the past 2 decades in three regions: eastern China, the continental United States and Europe. The model successfully reproduced the observed decreasing trends in SO2, NO2, 8 h O3 maxima, SO42− and elemental carbon (EC) in the US and Europe. However, the model fails to reproduce the decreasing trends in NO3− in the US, potentially pointing to uncertainties of NH3 emissions. The model failed to capture the 6-year trends of SO2 and NO2 in CN-API (China – Air Pollution Index) from 2005 to 2010, but reproduced the observed pattern of O3 trends shown in three World Data Centre for Greenhouse Gases (WDCGG) sites over eastern Asia. Due to the coarse spatial resolution employed in these calculations, predicted SO2 and NO2 concentrations are underestimated relative to all urban networks, i.e., US-AQS (US – Air Quality System; normalized mean bias (NMB) = −38% and −48%), EU-AIRBASE (European Air quality data Base; NMB = −18 and −54%) and CN-API (NMB = −36 and −68%). Conversely, at the rural network EU-EMEP (European Monitoring and Evaluation Programme), SO2 is overestimated (NMB from 4 to 150%) while NO2 is simulated well (NMB within ±15%) in all seasons. Correlations between simulated and observed O3 wintertime daily 8 h maxima (DM8) are poor compared to other seasons for all networks. Better correlation between simulated and observed SO42− was found compared to that for SO2. Underestimation of summer SO42− in the US may be associated with the uncertainty in precipitation and associated wet scavenging representation in the model. The model exhibits worse performance for NO3− predictions, particularly in summer, due to high uncertainties in the gas/particle partitioning of NO3− as well as seasonal variations of NH3 emissions. There are high correlations (R > 0.5) between observed and simulated EC, although the model underestimates the EC concentration by 65% due to the coarse grid resolution as well as uncertainties in the PM speciation profile associated with EC emissions. The almost linear response seen in the trajectory of modeled O3 changes in eastern China over the past 2 decades suggests that control strategies that focus on combined control of NOx and volatile organic compound (VOC) emissions with a ratio of 0.46 may provide the most effective means for O3 reductions for the region devoid of nonlinear response potentially associated with NOx or VOC limitation resulting from alternate strategies. The response of O3 is more sensitive to changes in NOx emissions in the eastern US because the relative abundance of biogenic VOC emissions tends to reduce the effectiveness of VOC controls. Increasing NH3 levels offset the relative effectiveness of NOx controls in reducing the relative fraction of aerosol NO3− formed from declining NOx emissions in the eastern US, while the control effectiveness was assured by the simultaneous control of NH3 emission in Europe.

Urban form and air quality in the United States

2015 ◽  
Vol 139 ◽  
pp. 168-179 ◽  
Author(s):  
Joshua McCarty ◽  
Nikhil Kaza
Keyword(s):  
United States ◽  
Air Quality ◽  
Urban Form ◽  
The United States

Mechanisms Contributing to the Warming Hole and the Consequent U.S. East–West Differential of Heat Extremes

2012 ◽  
Vol 25 (18) ◽  
pp. 6394-6408 ◽  
Author(s):  
Gerald A. Meehl ◽  
Julie M. Arblaster ◽  
Grant Branstator
Keyword(s):  
United States ◽  
Twentieth Century ◽  
Linear Trend ◽  
Coupled Model ◽  
The United States ◽  
Convective Heating ◽  
Central Pacific ◽  
Southeastern Part ◽  
Climate System Model ◽  
East West

Abstract A linear trend calculated for observed annual mean surface air temperatures over the United States for the second-half of the twentieth century shows a slight cooling over the southeastern part of the country, the so-called warming hole, while temperatures over the rest of the country rose significantly. This east–west gradient of average temperature change has contributed to the observed pattern of changes of record temperatures as given by the ratio of daily record high temperatures to record low temperatures with a comparable east–west gradient. Ensemble averages of twentieth-century climate simulations in the Community Climate System Model, version 3 (CCSM3), show a slight west–east warming gradient but no warming hole. A warming hole appears in only several ensemble members in the Coupled Model Intercomparison Project phase 3 (CMIP3) multimodel dataset and in one ensemble member of simulated twentieth-century climate in CCSM3. In this model the warming hole is produced mostly from internal decadal time-scale variability originating mainly from the equatorial central Pacific associated with the Interdecadal Pacific Oscillation (IPO). Analyses of a long control run of the coupled model, and specified convective heating anomaly experiments in the atmosphere-only version of the model, trace the forcing of the warming hole to positive convective heating anomalies in the central equatorial Pacific Ocean near the date line. Cold-air advection into the southeastern United States in winter, and low-level moisture convergence in that region in summer, contribute most to the warming hole in those seasons. Projections show a disappearance of the warming hole, but ongoing greater surface temperature increases in the western United States compared to the eastern United States.

scholarly journals Life cycle air quality impacts on human health from potential switchgrass production in the United States

2018 ◽  
Vol 114 ◽  
pp. 73-82 ◽  
Author(s):  
Sumil K. Thakrar ◽  
Andrew L. Goodkind ◽  
Christopher W. Tessum ◽  
Julian D. Marshall ◽  
Jason D. Hill
Keyword(s):  
United States ◽  
Life Cycle ◽  
Air Quality ◽  
Human Health ◽  
The United States

scholarly journals Air Pollution Increases Influenza Hospitalizations

2020 ◽  
Author(s):  
Gregor Singer ◽  
Joshua Graff Zivin ◽  
Matthew Neidell ◽  
Nicholas Sanders
Keyword(s):  
United States ◽  
Air Pollution ◽  
Air Quality ◽  
Seasonal Influenza ◽  
Hospital Admissions ◽  
The United States ◽  
Inpatient Hospitalization ◽  
Vaccination Rates ◽  
Health Burden ◽  
Severe Influenza

AbstractSeasonal influenza is a recurring health burden shared widely across the globe. We study whether air quality affects the occurrence of severe influenza cases that require inpatient hospitalization. Using longitudinal information on local air quality and hospital admissions across the United States, we find that poor air quality increases the incidence of significant influenza hospital admissions. Effects diminish in years with greater influenza vaccine effectiveness. Apart from increasing vaccination rates, improving air quality may help reduce the spread and severity of influenza.

scholarly journals Source-receptor relationships between East Asian sulfur dioxide emissions and Northern Hemisphere sulfate concentrations

2008 ◽  
Vol 8 (2) ◽  
pp. 5537-5561 ◽  
Author(s):  
J. Liu ◽  
D. L. Mauzerall ◽  
L. W. Horowitz
Keyword(s):  
Northern Hemisphere ◽  
North Pacific ◽  
East Asian ◽  
Source Region ◽  
The United States ◽  
So2 Emissions ◽  
Aerosol Model ◽  
The North ◽  
The North Pacific ◽  
Sulfur Emissions

Abstract. We analyze the effect of varying East Asian (EA) sulfur emissions on sulfate concentrations in the Northern Hemisphere, using a global coupled oxidant-aerosol model (MOZART-2). We conduct a base and five sensitivity simulations, in which sulfur emissions from each continent are tagged, to establish the source-receptor (S-R) relationship between EA sulfur emissions and sulfate concentrations over source and downwind regions. We find that from west to east across the North Pacific, EA sulfate contributes approximately 80%–20% of sulfate at the surface, but at least 50% at 500 hPa. In addition, EA SO2 emissions account for approximately 30%–50% and 10%–20% of North American background sulfate over the western and eastern US, respectively. The contribution of EA sulfate to the western US at the surface is highest in MAM and JJA, but is lowest in DJF. Reducing EA SO2 emissions will significantly decrease the spatial extent of the EA sulfate influence over the North Pacific both at the surface and at 500 mb in all seasons, but the extent of influence is insensitive to emission increases, particularly in DJF and JJA. We find that EA sulfate concentrations over most downwind regions respond nearly linearly to changes in EA SO2 emissions, but sulfate concentrations over the EA source region increase more slowly than SO2 emissions, particularly at the surface and in winter, due to limited availability of oxidants (mostly H2O2). We find that similar estimates of the S-R relationship for trans-Pacific transport of EA sulfate would be obtained using either sensitivity or tagging techniques. Our findings suggest that future changes in EA sulfur emissions may cause little change in the sulfate induced health impact over downwind continents but SO2 emission reductions may significantly reduce the sulfate related climate cooling over the North Pacific and the United States.

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