@misc{172736,
  author = {Y. Xie and M. Lin and L. W. Horowitz},
  title = {Summer PM2.5 Pollution Extremes Caused by Wildfires Over the Western United States During 2017{\textendash}2018},
  abstract = { Abstract Using observations and model simulations (ESM4.1) during 1988{\textendash}2018, we show large year-to-year variability in western U.S. PM2.5 pollution caused by regional and distant fires. Widespread wildfires, combined with stagnation, caused summer PM2.5 pollution in 2017 and 2018 to exceed 2 standard deviations over long-term averages. ESM4.1 with a fire emission inventory constrained by satellite-derived fire radiative energy and aerosol optical depth captures the observed surface PM2.5 means and extremes above the 35~μg/m3 U.S. air quality standard. However, aerosol emissions from the widely used Global Fire Emissions Database (GFED) must be increased by 5 times for ESM4.1 to match observations. On days when observed PM2.5 reached 35{\textendash}175~μg/m3, wildfire emissions can explain 90\% of total PM2.5, with smoke transported from Canada contributing 25{\textendash}50\% in northern states, according to model sensitivity simulations. Fire emission uncertainties pose challenges to accurately assessing the impacts of fire smoke on air quality, radiation, and climate. },
  year = {2020},
  journal = {Geophysical Research Letters},
  volume = {47},
  pages = {e2020GL089429},
  isbn = {0094-8276},
  url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020GL089429},
  doi = {10.1029/2020GL089429},
  language = {eng},
}