Changes in future air quality, deposition, and aerosol-cloud interactions under future climate and emission scenarios

Journal Article · Mon Aug 01 04:00:00 EDT 2016 · Atmospheric Environment (1994)

DOI:https://doi.org/10.1016/j.atmosenv.2016.05.008· OSTI ID:1338197

Glotfelty, Timothy; Zhang, Yang; Karamchandani, Prakash; Streets, David G.

The prospect of global climate change will have wide scale impacts, such as ecological stress and human health hazards. One aspect of concern is future changes in air quality that will result from changes in both meteorological forcing and air pollutant emissions. In this study, the GU-WRF/Chem model is employed to simulate the impact of changing climate and emissions following the IPCC AR4 SRES A1B scenario. An average of 4 future years (2020, 2030, 2040, and 2050) is compared against an average of 2 current years (2001 and 2010). Under this scenario, by the Mid-21st century global air quality is projected to degrade with a global average increase of 2.5 ppb in the maximum 8-hr O₃ level and of 0.3 mg m³ in 24-hr average PM2.5. However, PM2.5 changes are more regional due to regional variations in primary aerosol emissions and emissions of gaseous precursor for secondary PM2.5. Increasing NOx emissions in this scenario combines with a wetter climate elevating levels of OH, HO₂, H₂O₂, and the nitrate radical and increasing the atmosphere’s near surface oxidation state. This differs from findings under the RCP scenarios that experience declines in OH from reduced NOx emissions, stratospheric recovery of O₃, and increases in CH₄ and VOCs. Increasing NO_x and O₃ levels enhances the nitrogen and O₃ deposition, indicating potentially enhanced crop damage and ecosystem stress under this scenario. The enhanced global aerosol level results in enhancements in aerosol optical depth, cloud droplet number concentration, and cloud optical thickness. This leads to dimming at the Earth’s surface with a global average reduction in shortwave radiation of 1.2 W m² . This enhanced dimming leads to a more moderate warming trend and different trends in radiation than those found in NCAR’s CCSM simulation, which does not include the advanced chemistry and aerosol treatment of GU-WRF/Chem and cannot simulate the impacts of changing climate and emissions with the same level of detailed treatments. This study indicates that effective climate mitigation and emission control strategies are needed to prevent future health impact and ecosystem stress. Further, studies that are used to develop these strategies should use fully coupled models with sophisticated chemical and aerosol-interaction treatments that can provide a more realistic representation of the atmosphere.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE; U.S. Environmental Protection Agency (EPA); National Science Foundation (NSF); U.S. Department of Agriculture (USDA)
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 1338197
• Journal Information: Atmospheric Environment (1994), Journal Name: Atmospheric Environment (1994) Journal Issue: C Vol. 139; ISSN 1352-2310
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
Aerosol direct effect
Aerosol indirect effects
Future air quality
GU_WRF/Chem
Global climate and emissions change
Online-coupled model