Impact of the 2008 Global Recession on air quality over the United States: Implications for surface ozone levels from changes in NO_x emissions

Authors

Daniel Tong, University of MarylandFollow
Li Pan, George Mason University
Weiwei Chen, NOAA Air Resources Laboratory
Lok Lamsal, Universities Space Research Association
Pius Lee, NOAA Air Resources Laboratory
Youhua Tang, George Mason University
Hyuncheol Kim, George Mason University
Shobha Kondragunta, NOAA Satellite and Information Service
Ivanka Stajner, NOAA National Weather Service

Date of this Version

2016

Citation

Tong, D., L. Pan, W. Chen, L. Lamsal, P. Lee, Y. Tang, H. Kim, S. Kondragunta, and I. Stajner (2016), Impact of the 2008 Global Recession on air quality over the United States: Implications for surface ozone levels from changes in NO_x emissions, Geophys. Res. Lett., 43, 9280–9288, doi:10.1002/2016GL069885.

Comments

U.S. government work.

Abstract

Satellite and ground observations detected large variability in nitrogen oxides (NO_x) during the 2008 economic recession, but the impact of the recession on air quality has not been quantified. This study combines observed NO_x trends and a regional chemical transport model to quantify the impact of the recession on surface ozone (O₃) levels over the continental United States. The impact is quantified by simulating O₃ concentrations under two emission scenarios: business-as-usual (BAU) and recession. In the BAU case, the emission projection from the Cross-State Air Pollution Rule is used to estimate the “would-be” NO_x emission level in 2011. In the recession case, the actual NO₂ trends observed from Air Quality System ground monitors and the Ozone Monitoring Instrument on the Aura satellite are used to obtain “realistic” changes in NO_x emissions. The model prediction with the recession effect agrees better with ground O₃ observations over time and space than the prediction with the BAU emission. The results show that the recession caused a 1–2 ppbv decrease in surface O₃ concentration over the eastern United States, a slight increase (0.5–1 ppbv) over the Rocky Mountain region, and mixed changes in the Pacific West. The gain in air quality benefits during the recession, however, could be quickly offset by the much slower emission reduction rate during the post-recession period.