Projecting Future Air Quality Under Energy Transition Scenarios over the U.S. using Online-Coupled Models

2021 ◽  
Author(s):  
Yang Zhang ◽  
Kai Wang ◽  
Daniel Schuch
Keyword(s):  
Air Quality ◽  
Linear Regression ◽  
Surface Ozone ◽  
Energy Transition ◽  
Air Pollutant ◽  
Atmospheric Composition ◽  
Atmospheric Conditions ◽  
Coupled Models ◽  
Ensemble Mean ◽  
Multi Linear Regression

<p> </p><p>Online-coupled meteorology-chemistry models provide powerful tools for more realistically simulation of current and future air quality with feedbacks between atmospheric composition and meteorology that cannot be considered in offline-coupled models. In this work, several state-of-science online-coupled models are applied to generate the best possible predictions of surface ozone (O<sub>3</sub>) and fine particulate matter (PM<sub>2.5</sub>) concentrations under current emission and climate conditions. Two ensemble methods are used to further reduce the model biases and errors including a simple ensemble mean based on an average of ensemble members, and a weighted ensemble mean based on the multi-linear regression. The skills of individual models and their ensembles are evaluated using available surface network data.  Compared to individual models and the simple ensemble mean, the weighted ensemble predictions based on the multi-linear regression perform the best overall for both O<sub>3</sub> and PM<sub>2.5</sub>. The model with best performance is selected to apply for future years to project the changes in air quality under various energy transition scenarios to support the development of emission control strategies. These results illustrate the current capability of the online-coupled models and the potential of weighted ensemble in generating the best possible estimates of air pollutant concentrations under current and future atmospheric conditions. </p>

scholarly journals Impacts of aerosol-cloud interactions on past and future changes in tropospheric composition

2009 ◽  
Vol 9 (12) ◽  
pp. 4115-4129 ◽  
Author(s):  
N. Unger ◽  
S. Menon ◽  
D. M. Koch ◽  
D. T. Shindell
Keyword(s):  
Air Quality ◽  
Wet Deposition ◽  
Wide Spectrum ◽  
Surface Ozone ◽  
Tropospheric Chemistry ◽  
Atmospheric Composition ◽  
Sulfate Production ◽  
Aerosol Cloud ◽  
Aerosol Cloud Interactions ◽  
The Impact

Abstract. The development of effective emissions control policies that are beneficial to both climate and air quality requires a detailed understanding of all the feedbacks in the atmospheric composition and climate system. We perform sensitivity studies with a global atmospheric composition-climate model to assess the impact of aerosols on tropospheric chemistry through their modification on clouds, aerosol-cloud interactions (ACI). The model includes coupling between both tropospheric gas-phase and aerosol chemistry and aerosols and liquid-phase clouds. We investigate past impacts from preindustrial (PI) to present day (PD) and future impacts from PD to 2050 (for the moderate IPCC A1B scenario) that embrace a wide spectrum of precursor emission changes and consequential ACI. The aerosol indirect effect (AIE) is estimated to be −2.0 Wm−2 for PD-PI and −0.6 Wm−2 for 2050-PD, at the high end of current estimates. Inclusion of ACI substantially impacts changes in global mean methane lifetime across both time periods, enhancing the past and future increases by 10% and 30%, respectively. In regions where pollution emissions increase, inclusion of ACI leads to 20% enhancements in in-cloud sulfate production and ~10% enhancements in sulfate wet deposition that is displaced away from the immediate source regions. The enhanced in-cloud sulfate formation leads to larger increases in surface sulfate across polluted regions (~10–30%). Nitric acid wet deposition is dampened by 15–20% across the industrialized regions due to ACI allowing additional re-release of reactive nitrogen that contributes to 1–2 ppbv increases in surface ozone in outflow regions. Our model findings indicate that ACI must be considered in studies of methane trends and projections of future changes to particulate matter air quality.

scholarly journals Stratospheric ozone changes under solar geoengineering: implications for UV exposure and air quality

2016 ◽  
Vol 16 (6) ◽  
pp. 4191-4203 ◽  
Author(s):  
Peer Johannes Nowack ◽  
Nathan Luke Abraham ◽  
Peter Braesicke ◽  
John Adrian Pyle
Keyword(s):  
Air Quality ◽  
Atmospheric Carbon Dioxide ◽  
Climate Model ◽  
Stratospheric Ozone ◽  
Surface Ozone ◽  
Atmospheric Composition ◽  
Specific Humidity ◽  
Uv Exposure ◽  
Solar Radiation Management ◽  
Global Mean

Abstract. Various forms of geoengineering have been proposed to counter anthropogenic climate change. Methods which aim to modify the Earth's energy balance by reducing insolation are often subsumed under the term solar radiation management (SRM). Here, we present results of a standard SRM modelling experiment in which the incoming solar irradiance is reduced to offset the global mean warming induced by a quadrupling of atmospheric carbon dioxide. For the first time in an atmosphere–ocean coupled climate model, we include atmospheric composition feedbacks for this experiment. While the SRM scheme considered here could offset greenhouse gas induced global mean surface warming, it leads to important changes in atmospheric composition. We find large stratospheric ozone increases that induce significant reductions in surface UV-B irradiance, which would have implications for vitamin D production. In addition, the higher stratospheric ozone levels lead to decreased ozone photolysis in the troposphere. In combination with lower atmospheric specific humidity under SRM, this results in overall surface ozone concentration increases in the idealized G1 experiment. Both UV-B and surface ozone changes are important for human health. We therefore highlight that both stratospheric and tropospheric ozone changes must be considered in the assessment of any SRM scheme, due to their important roles in regulating UV exposure and air quality.

scholarly journals Adverse Effects of Increasing Drought on Air Quality via Natural Processes

2017 ◽  
Author(s):  
Yuxuan Wang ◽  
Yuanyu Xie ◽  
Wenhao Dong ◽  
Yi Ming ◽  
Jun Wang ◽  
...  
Keyword(s):  
Air Quality ◽  
Climate Model ◽  
Surface Ozone ◽  
Ground Level ◽  
Atmospheric Composition ◽  
Drought Severity ◽  
Severe Drought ◽  
Dust Deposition ◽  
Natural Processes ◽  
The Us

Abstract. Drought is a recurring extreme of the climate system with well-documented impacts on agriculture and water resources. The strong perturbation of drought to the land biosphere and atmospheric water cycle will affect atmospheric composition, the nature and extent of which are not well understood. Here we present observational evidence that surface ozone and PM2.5 in the US are significantly correlated with drought severity, with 3.5 ppbv (8 %) and 1.6 μg m−3 (17 %) increases respectively under severe drought. These enhancements show little sensitivity to the decreasing trend of US anthropogenic emissions, indicating natural processes as the primary cause. Elevated ozone and PM2.5 are attributed to the combined effects of drought on natural emissions (wildfires, biogenic VOCs and dust), deposition, and chemistry. Most climate-chemistry models are not able to reproduce the observed responses of ozone and PM2.5 to drought severity, suggesting a lack of mechanistic understanding of drought effects on atmospheric composition. The model deficiencies are partly attributed to the lack of drought-induced changes in land-atmosphere exchanges of reactive gases and particles and misrepresentation of cloud changes under drought conditions. By applying the observed relationships between drought and air pollutants to climate model projected drought occurrences, we estimate an increase of 1–6 % for ground-level O3 and 1–16 % for PM2.5 in the US by 2100 compared to the 2000s due to increasing drought alone. Drought thus poses another aspect of climate change penalty on air quality not recognized before. Improvements in the models are imperative to facilitate better prediction of air quality challenges due to changing hydroclimate and atmospheric composition feedback to climate.

scholarly journals Evaluation of Downscaled CMIP5 Coupled with VIC Model for Flash Drought Simulation in a Humid Subtropical Basin, China

2018 ◽  
Vol 31 (3) ◽  
pp. 1075-1090 ◽  
Author(s):  
Yuqing Zhang ◽  
Qinglong You ◽  
Changchun Chen ◽  
Jing Ge ◽  
Muhammad Adnan
Keyword(s):  
Heat Waves ◽  
Coupled Model ◽  
Cmip5 Models ◽  
Atmospheric Conditions ◽  
Multimodel Ensemble ◽  
Infiltration Capacity ◽  
Coupled Models ◽  
Vic Model ◽  
Ensemble Mean ◽  
Meteorological Observations

Abstract Compared to traditional drought events, flash droughts evolve rapidly during short-term extreme atmospheric conditions, with a lasting period of one pentad to several weeks. There are two main categories of flash droughts: the heat wave flash drought (HWFD), which is mainly caused by persistent high temperatures (heat waves), and the precipitation deficit flash drought (PDFD), which is mainly triggered by precipitation deficits. The authors’ previous research focused on the characteristics and causes of flash drought based on meteorological observations and Variable Infiltration Capacity (VIC) model simulations in a humid subtropical basin (Gan River basin, China). In this study, the authors evaluated the downscaled phase 5 of the Coupled Model Intercomparison Project (CMIP5) models’ simulations, coupled with the VIC model (CMIP5–VIC) in reproducing flash droughts in a humid subtropical basin in China. Most downscaled CMIP5–VIC simulations can reproduce the spatial patterns of flash droughts with respect to the benchmarks. The coupled models fail to readily replicate interannual variation (interannual pentad change), but most models can reflect the interannual variability (temporal standard deviation) and long-term average pentads of flash droughts. It is difficult to simultaneously depict both the spatial and temporal features of flash droughts within only one coupled model. The climatological patterns of the best multimodel ensemble mean are close to those of the all-model ensemble mean, but the best multimodel ensemble mean has a minimal bias range and relatively low computational burden.

scholarly journals Ozone changes under solar geoengineering: implications for UV exposure and air quality

2015 ◽  
Vol 15 (21) ◽  
pp. 31973-32004 ◽  
Author(s):  
P. J. Nowack ◽  
N. L. Abraham ◽  
P. Braesicke ◽  
J. A. Pyle
Keyword(s):  
Air Quality ◽  
Atmospheric Carbon Dioxide ◽  
Climate Model ◽  
Stratospheric Ozone ◽  
Surface Ozone ◽  
Atmospheric Composition ◽  
Uv Exposure ◽  
Solar Radiation Management ◽  
Solar Geoengineering ◽  
Radiation Management

Abstract. Various forms of geoengineering have been proposed to counter anthropogenic climate change. Methods which aim to modify the Earth's energy balance by reducing insolation are often subsumed under the term Solar Radiation Management (SRM). Here, we present results of a standard SRM modelling experiment in which the incoming solar irradiance is reduced to offset the global mean warming induced by a quadrupling of atmospheric carbon dioxide. For the first time in an atmosphere–ocean coupled climate model, we include atmospheric composition feedbacks such as ozone changes under this scenario. Including the composition changes, we find large reductions in surface UV-B irradiance, with implications for vitamin D production, and increases in surface ozone concentrations, both of which could be important for human health. We highlight that both tropospheric and stratospheric ozone changes should be considered in the assessment of any SRM scheme, due to their important roles in regulating UV exposure and air quality.

scholarly journals Adverse effects of increasing drought on air quality via natural processes

2017 ◽  
Vol 17 (20) ◽  
pp. 12827-12843 ◽  
Author(s):  
Yuxuan Wang ◽  
Yuanyu Xie ◽  
Wenhao Dong ◽  
Yi Ming ◽  
Jun Wang ◽  
...  
Keyword(s):  
Air Quality ◽  
Climate Model ◽  
Water Cycle ◽  
Surface Ozone ◽  
Ground Level ◽  
Atmospheric Composition ◽  
Drought Severity ◽  
Natural Processes ◽  
Elevated Ozone ◽  
Effects Of Drought

Abstract. Drought is a recurring extreme of the climate system with well-documented impacts on agriculture and water resources. The strong perturbation of drought to the land biosphere and atmospheric water cycle will affect atmospheric composition, the nature and extent of which are not well understood. Here we present observational evidence that US air quality is significantly correlated with drought severity. Severe droughts during the period of 1990–2014 were found associated with growth-season (March–October) mean enhancements in surface ozone and PM2.5 of 3.5 ppbv (8 %) and 1.6 µg m−3 (17 %), respectively. The pollutant enhancements associated with droughts do not appear to be affected by the decreasing trend of US anthropogenic emissions, indicating natural processes as the primary cause. Elevated ozone and PM2.5 are attributed to the combined effects of drought on deposition, natural emissions (wildfires, biogenic volatile organic compounds (BVOCs), and dust), and chemistry. Most climate–chemistry models are not able to reproduce the observed correlations of ozone and PM2.5 to drought severity. The model deficiencies are partly attributed to the lack of drought-induced changes in land–atmosphere exchanges of reactive gases and particles and misrepresentation of cloud changes under drought conditions. By applying the observed relationships between drought and air pollutants to climate model projected drought occurrences, we estimate an increase of 1–6 % for ground-level O3 and 1–16 % for PM2.5 in the US by 2100 compared to the 2000s due to increasing drought alone. Drought thus poses an important aspect of climate change penalty on air quality, and a better prediction of such effects would require improvements in model processes.

scholarly journals Comprehensive isoprene and terpene gas-phase chemistry improves simulated surface ozone in the southeastern US

2020 ◽  
Vol 20 (6) ◽  
pp. 3739-3776 ◽  
Author(s):  
Rebecca H. Schwantes ◽  
Louisa K. Emmons ◽  
John J. Orlando ◽  
Mary C. Barth ◽  
Geoffrey S. Tyndall ◽  
...  
Keyword(s):  
Surface Ozone ◽  
Air Pollutant ◽  
Atmospheric Composition ◽  
Daily Maximum ◽  
Global Models ◽  
Field Campaign ◽  
Southeastern Us ◽  
Simulated Surface ◽  
Terpene Oxidation ◽  
The Impact

Abstract. Ozone is a greenhouse gas and air pollutant that is harmful to human health and plants. During the summer in the southeastern US, many regional and global models are biased high for surface ozone compared to observations. Past studies have suggested different solutions including the need for updates to model representation of clouds, chemistry, ozone deposition, and emissions of nitrogen oxides (NOx) or biogenic hydrocarbons. Here, due to the high biogenic emissions in the southeastern US, more comprehensive and updated isoprene and terpene chemistry is added into CESM/CAM-chem (Community Earth System Model/Community Atmosphere Model with full chemistry) to evaluate the impact of chemistry on simulated ozone. Comparisons of the model results with data collected during the Studies of Emissions Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) field campaign and from the US EPA (Environmental Protection Agency) CASTNET (Clean Air Status and Trends Network) monitoring stations confirm the updated chemistry improves simulated surface ozone, ozone precursors, and NOx reservoir compounds. The isoprene and terpene chemistry updates reduce the bias in the daily maximum 8 h average (MDA8) surface ozone by up to 7 ppb. In the past, terpene oxidation in particular has been ignored or heavily reduced in chemical schemes used in many regional and global models, and this study demonstrates that comprehensive isoprene and terpene chemistry is needed to reduce surface ozone model biases. Sensitivity tests were performed in order to evaluate the impact of lingering uncertainties in isoprene and terpene oxidation on ozone. Results suggest that even though isoprene emissions are higher than terpene emissions in the southeastern US, remaining uncertainties in isoprene and terpene oxidation have similar impacts on ozone due to lower uncertainties in isoprene oxidation. Additionally, this study identifies the need for further constraints on the aerosol uptake of organic nitrates derived from isoprene and terpenes in order to reduce uncertainty in simulated ozone. Although the updates to isoprene and terpene chemistry greatly reduce the ozone bias in CAM-chem, a large bias remains. Evaluation against SEAC4RS field campaign results suggests future improvements to horizontal resolution and cloud parameterizations in CAM-chem may be particularly important for further reducing this bias.

scholarly journals Impacts of near-future cultivation of biofuel feedstocks on atmospheric composition and local air quality

2012 ◽  
Vol 12 (2) ◽  
pp. 919-939 ◽  
Author(s):  
K. Ashworth ◽  
G. Folberth ◽  
C. N. Hewitt ◽  
O. Wild
Keyword(s):  
Land Use ◽  
Air Quality ◽  
Oil Palm ◽  
Large Scale ◽  
Global Climate ◽  
Surface Ozone ◽  
Regional Scale ◽  
Atmospheric Composition ◽  
Scale Production ◽  
Reactive Trace Gases

Abstract. Large-scale production of feedstock crops for biofuels will lead to land use changes. We quantify the effects of realistic land use change scenarios for biofuel feedstock production on isoprene emissions and hence atmospheric composition and chemistry using the HadGEM2 model. Two feedstocks are considered: oil palm for biodiesel in the tropics and short rotation coppice (SRC) in the mid-latitudes. In total, 69 Mha of oil palm and 9 Mha of SRC are planted, each sufficient to replace just over 1% of projected global fossil fuel demand in 2020. Both planting scenarios result in increases in total global annual isoprene emissions of about 1%. In each case, changes in surface concentrations of ozone and biogenic secondary organic aerosol (bSOA) are substantial at the regional scale, with implications for air quality standards. However, the changes in tropospheric burden of ozone and the OH radical, and hence effects on global climate, are negligible. Over SE Asia, one region of oil palm planting, increases in annual mean surface ozone and bSOA concentrations reach over 3 ppbv (+11%) and 0.4 μg m−3 (+10%) respectively for parts of Borneo, with monthly mean increases of up to 6.5 ppbv (+25%) and 0.5 μg m−3 (+12%). Under the SRC scenario, Europe experiences monthly mean changes of over 0.6 ppbv (+1%) and 0.1 μg m−3 (+5%) in June and July, with peak increases of over 2 ppbv (+3%) and 0.5 μg m−3 (+8 %). That appreciable regional atmospheric impacts result from low level planting scenarios demonstrates the need to include changes in emissions of reactive trace gases such as isoprene in life cycle assessments performed on potential biofuel feedstocks.

scholarly journals Impacts of future land use and land cover change on mid-21st-century surface ozone air quality: distinguishing between the biogeophysical and biogeochemical effects

2020 ◽  
Vol 20 (19) ◽  
pp. 11349-11369
Author(s):  
Lang Wang ◽  
Amos P. K. Tai ◽  
Chi-Yung Tam ◽  
Mehliyar Sadiq ◽  
Peng Wang ◽  
...  
Keyword(s):  
Land Use ◽  
Air Quality ◽  
Land Cover ◽  
Land Cover Change ◽  
Dry Deposition ◽  
Large Scale ◽  
Surface Ozone ◽  
Air Pollutant ◽  
Boreal Summer ◽  
Ozone Pollution

Abstract. Surface ozone (O3) is an important air pollutant and greenhouse gas. Land use and land cover is one of the critical factors influencing ozone, in addition to anthropogenic emissions and climate. Land use and land cover change (LULCC) can on the one hand affect ozone “biogeochemically”, i.e., via dry deposition and biogenic emissions of volatile organic compounds (VOCs). LULCC can on the other hand alter regional- to large-scale climate through modifying albedo and evapotranspiration, which can lead to changes in surface temperature, hydrometeorology, and atmospheric circulation that can ultimately impact ozone “biogeophysically”. Such biogeophysical effects of LULCC on ozone are largely understudied. This study investigates the individual and combined biogeophysical and biogeochemical effects of LULCC on ozone and explicitly examines the critical pathway for how LULCC impacts ozone pollution. A global coupled atmosphere–chemistry–land model is driven by projected LULCC from the present day (2000) to the future (2050) under RCP4.5 and RCP8.5 scenarios, focusing on the boreal summer. Results reveal that when considering biogeochemical effects only, surface ozone is predicted to have slight changes by up to 2 ppbv maximum in some areas due to LULCC. It is primarily driven by changes in isoprene emission and dry deposition counteracting each other in shaping ozone. In contrast, when considering the combined effect of LULCC, ozone is more substantially altered by up to 5 ppbv over several regions in North America and Europe under RCP4.5, reflecting the importance of biogeophysical effects on ozone changes. In boreal and temperate mixed forests with intensive reforestation, enhanced net radiation and sensible heat induce a cascade of hydrometeorological feedbacks that generate warmer and drier conditions favorable for higher ozone levels. In contrast, reforestation in subtropical broadleaf forests has minimal impacts on boundary-layer meteorology and ozone air quality. Furthermore, significant ozone changes are also found in regions with only modest LULCC, which can only be explained by “remote” biogeophysical effects. A likely mechanism is that reforestation induces a circulation response, leading to reduced moisture transport and ultimately warmer and drier conditions in the surrounding regions with limited LULCC. We conclude that the biogeophysical effects of LULCC are important pathways through which LULCC influences ozone air quality both locally and in remote regions even without significant LULCC. Overlooking the effects of hydrometeorological changes on ozone air quality may cause underestimation of the impacts of LULCC on ozone pollution.

scholarly journals Comprehensive isoprene and terpene chemistry improves simulated surface ozone in the southeastern U.S.

2019 ◽  
Author(s):  
Rebecca H. Schwantes ◽  
Louisa K. Emmons ◽  
John J. Orlando ◽  
Mary C. Barth ◽  
Geoffrey S. Tyndall ◽  
...  
Keyword(s):  
Surface Ozone ◽  
Air Pollutant ◽  
Atmospheric Composition ◽  
Daily Maximum ◽  
Organic Nitrates ◽  
Global Models ◽  
Model Community ◽  
Simulated Surface ◽  
Terpene Oxidation ◽  
The Impact

Abstract. Ozone is a greenhouse gas and air pollutant that is harmful to human health and plants. During the summer in the southeastern U.S., many regional and global models are biased high for surface ozone compared to observations. Past studies have suggested different solutions including the need for updates to model representation of clouds, chemistry, ozone deposition, and emissions of nitrogen oxides (NOx) or biogenic hydrocarbons. Here due to the high biogenic emissions in the southeastern U.S., more comprehensive and updated isoprene and terpene chemistry is added into CESMTM/CAM-chem (Community Earth System Model/Community Atmosphere Model with chemistry) to evaluate the impact of chemistry on simulated ozone. Comparisons of the model results with data collected during the Studies of Emissions Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) field campaign and U.S. EPA CASTNET monitoring stations confirm the updated chemistry improves simulated surface ozone, ozone precursors, and NOx reservoir compounds. The isoprene and terpene chemistry updates reduce the bias in the daily maximum 8-hr average (MDA8) surface ozone by up to 7 ppb. In the past, terpene oxidation in particular has been ignored or heavily reduced in chemical schemes used in many regional and global models, and this study demonstrates comprehensive isoprene and terpene chemistry is needed to reduce surface ozone model biases. Sensitivity tests were performed in order to evaluate the impact of lingering uncertainties in isoprene and terpene oxidation on ozone. Results suggest that even though isoprene emissions are higher than terpene emissions in the southeastern U.S., remaining uncertainties in isoprene and terpene oxidation have similar impacts on ozone due to lower uncertainties in isoprene oxidation. Additionally, this study identifies the need for further constraints on aerosol uptake of organic nitrates derived from isoprene and terpenes in order to reduce uncertainty in simulated ozone.

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