Mar 1, 2017

US surface ozone trends and extremes from 1980 to 2014: quantifying the roles of rising Asian emissions, domestic controls, wildfires, and climate

Lin, Meiyun, Horowitz, Larry W., Payton, Richard, Fiore, Arlene M., Tonnesen, Gail
Atmospheric Chemistry and Physics
  • States that US surface ozone (O3) responds to varying global-to-regional precursor emissions, climate, and extreme weather, with implications for designing effective air quality control policies
  • Examines these conjoined processes with observations and global chemistry-climate model hindcasts over 1980–2014
  • Finds that Asian emissions of nitrogen oxides (NOx) have tripled since 1990, contributing as much as 65 % to modeled springtime background O3 increases (0.3–0.5 ppb yr−1) over the western US (WUS), outpacing O3 decreases attained via 50 % US NOx emission controls
  • Finds that during summer, increasing Asian emissions roughly offset the benefits of US emission reductions
  • Concludes that high temperatures and the associated buildup of O3 produced from regional anthropogenic emissions contribute most to elevating observed summertime O3 throughout the USA