The potential effects of climate change on air quality across the conterminous US at 2030 under three Representative Concentration Pathways

Abstract

Abstract. The potential impacts of climate change on regional ozone (O3) and fine particulate (PM2.5) air quality in the United States (US) are investigated by linking global climate simulations with regional-scale meteorological and chemical transport models. Regional climate at 2000 and at 2030 under three Representative Concentration Pathways (RCPs) is simulated by using the Weather Research and Forecasting (WRF) model to downscale 11-year time slices from the Community Earth System Model (CESM). The downscaled meteorology is then used with the Community Multiscale Air Quality (CMAQ) model to simulate air quality during each of these 11-year periods. The analysis isolates the future air quality differences arising from climate-driven changes in meteorological parameters and specific natural emissions sources that are strongly influenced by meteorology. Other factors that will affect future air quality, such as anthropogenic air pollutant emissions and chemical boundary conditions, are unchanged across the simulations. The regional climate fields represent historical daily maximum and daily minimum temperatures well, with mean biases of less than 2 K for most regions of the US and most seasons of the year and good representation of variability. Precipitation in the central and eastern US is well simulated for the historical period, with seasonal and annual biases generally less than 25 %, with positive biases exceeding 25 % in the western US throughout the year and in part of the eastern US during summer. Maximum daily 8 h ozone (MDA8 O3) is projected to increase during summer and autumn in the central and eastern US. The increase in summer mean MDA8 O3 is largest under RCP8.5, exceeding 4 ppb in some locations, with smaller seasonal mean increases of up to 2 ppb simulated during autumn and changes during spring generally less than 1 ppb. Increases are magnified at the upper end of the O3 distribution, particularly where projected increases in temperature are greater. Annual average PM2.5 concentration changes range from −1.0 to 1.0 µg m−3. Organic PM2.5 concentrations increase during summer and autumn due to increased biogenic emissions. Aerosol nitrate decreases during winter, accompanied by lesser decreases in ammonium and sulfate, due to warmer temperatures causing increased partitioning to the gas phase. Among meteorological factors examined to account for modeled changes in pollution, temperature and isoprene emissions are found to have the largest changes and the greatest impact on O3 concentrations.

Climate change penalty and benefit on surface ozone: a global perspective based on CMIP6 earth system models

“…Hence, compensating effects from these processes and model differences in parameterizations of BVOC and lightning NO x emissions, and STE lead to low sensitivity of surface ozone to climate change and lack of model agreement for the sign of changes under global warming. The above mentioned heterogeneity in model results is also found in previous regional studies focusing on North America (Gonzalez-Abraham et al 2015, Val Martin et al 2015, Schnell et al 2016, He et al 2018, Nolte et al 2018, Rieder et al 2018 or Europe (Katragkou et al 2011, Colette et al 2015, Lacressonnière et al 2016, Schnell et al 2016, Fortems-Cheiney et al 2017. For European land areas, previous studies have estimated a summertime average ozone climate penalty as a function of the average European surface temperature anomaly of +0.17 ppbv • C −1 (Colette et al 2015), which is consistent with the estimated range of 0 to +0.2 ppbv • C −1 inferred by the multi-model mean of CMIP6 models over parts of Europe.…”

“…The above-mentioned IPCC AR5 assessment is also supported by several recent studies based on model projections either with global or regional models. The majority of the regional studies are focusing on North America (Gonzalez-Abraham et al 2015, Val Martin et al 2015, Schnell et al 2016, He et al 2018, Nolte et al 2018, Rieder et al 2018, Gao et al 2020 or Europe (Colette et al 2015, Lacressonnière et al 2016, Schnell et al 2016, Fortems-Cheiney et al 2017, but there are also a few studies focused on East Asia (Lee et al 2015, Schnell et al 2016 and India (Pommier et al 2018). Over polluted regions of the world, such as in North America, Europe, and East Asia, model studies project a general increase of surface ozone levels in a future warmer climate, particularly during summertime as has been recently reviewed (Fu and Tian 2019).…”

Estimating PM2.5-related premature mortality and morbidity associated with future wildfire emissions in the western US

“…Regarding time-varying meteorology, in our study running GEOS-Chem with future meteorology was not possible since the model was not configured to use outputs from global climate models. Recent evidence suggests, however, that our use of present-day meteorological fields when simulating wildfire emissions effects on PM 2.5 concentrations likely leads to underestimated impacts on wildfire-related PM 2.5 due to a shorter lifetime of PM 2.5 than might be expected in the future in areas projected to experience reductions in precipitation [ 29 , 43 , 44 ]. The net effects of climate change on meteorology remain important for estimating PM 2.5 concentrations.…”

Review on Polymeric, Inorganic, and Composite Materials for Air Filters: From Processing to Properties

“…[23] In addition, climate change is expected to exacerbate further human health impacts by increasing weather conditions that enhance air pollution exposure, mainly to PM 2.5 and ozone. [24,25] To break the cycle of air pollution and climate change, air pollution needs to be restricted more drastically. In this regard, air filters provide a suitable method for air purification.…”