2017 Progress Report: Effects of Changes in Climate and Land Use on U.S. Dust and Wildfire Particulate Matter

EPA Grant Number: R835875
Title: Effects of Changes in Climate and Land Use on U.S. Dust and Wildfire Particulate Matter
Investigators: Mickley, Loretta J. , Jacob, Daniel J. , Kaplan, Jed
Institution: Harvard University , ARVE Research Sarl
EPA Project Officer: Chung, Serena
Project Period: January 1, 2016 through December 31, 2018 (Extended to December 31, 2020)
Project Period Covered by this Report: January 1, 2017 through December 31,2017
Project Amount: $719,780
RFA: Particulate Matter and Related Pollutants in a Changing World (2014) RFA Text |  Recipients Lists
Research Category: Air , Climate Change


The project goals are to: (1) quantify the effects of climate change and land use on dust mobilization and transport within the western United States, (2) quantify the impact of climate change on Asian dust influence over the western United States, and (3) provide fine-scale projections of wildfire smoke for the future climate in the West.

Progress Summary:


We wrapped up our investigation of the dominant spatial patterns of observed fine dust interannual variability in the western United States and the meteorological factors that control these patterns for each of the spring months (March–May) during 2002–2015. For this project, we developed a prediction model to explore what may have caused the observed increase in March monthly mean fine dust concentrations in the Southwest over this time period. We then investigated the present-day sensitivity of fine dust levels in the U.S. Southwest to regional drought conditions and used the observed relationships to estimate future drought-driven changes in fine dust levels and associated health impacts in the Southwest. We also contributed to a project at Yale that seeks to understand the health impacts of wildfire smoke in the western United States.


Project 1. Consistent with previous studies, we found that March monthly mean fine dust concentrations have increased from 2002 to 2015 in the Southern California and Southwest regions by 0.09 ± 0.07 μg m-3 y-1. Using multiple linear regression analysis, we found that 76 percent of the variance in observed March fine dust concentrations averaged over the Southwest can be explained by a combination of two predictors: (1) the January–March Pacific Decadal Oscillation index and (2) long-term regional drought. For Southern California, the following predictors capture 81 percent of the temporal variability: (1) regional monthly mean relative humidity, (2) variability in the strength of trans-Pacific transport of Asian dust during March and (3) regional JFM SPEI48.

Project 2. Empirical Orthogonal Function analysis reveals that the dominant mode of fine dust interannual variability for each season in the Southwest consists of a pattern of large-scale covariability. This mode is correlated to the Standardized Precipitation-Evapotranspiration Index (SPEI) accumulated over 1–12 months in local and surrounding regions spanning the major North American deserts. Across the seasons, a unit decrease in SPEI02 averaged over different domains within the U.S. Southwest and northern Mexico is associated with increases in Southwest fine dust of 0.22–0.43 μg/m3. We applied these sensitivities to meteorological output from 23 climate models, and estimated future drought-driven increases in seasonal mean fine dust of 0.06–0.14 μg/m3 (9–23%) under RCP2.6 and 0.24-0.83 μg/m3 (43–70%) under RCP8.5 by the end of this century, relative to the present-day. Our results highlight a climate penalty that has important socioeconomic and policy implications for the U.S. Southwest but is not yet widely recognized.

Project 3. With collaborators at Yale University, we estimated exposure to PM2.5 specifically from wildfires and associations between wildfire-specific PM2.5 and respiratory hospital admissions for subpopulations ≥65 years of age in the western United States (2004–2009). We found that compared to other populations, higher fractions of blacks and people in urban counties and in California are exposed to more than one smoke wave per year, where smoke waves are defined as high-pollution episodes from wildfire smoke. Our study raised important environmental justice issues that can inform public health programs and wildfire management.

Future Activities:

In Year 3 we will focus on the following activities:

  1. Using LPJ-LMfire, we will quantify the effects of near-term climate change and trends in land use on vegetation and soil variables in the western United States.
  2. We will use the nested-grid version of GEOS-Chem to quantify the effects of regional changes in climate and land use on dust concentrations in the western United States. Our approach will involve implementing LPJ land cover variables into the fine-scale GEOS-Chem and diagnosing the trends in dust mobilization and concentration in the 2000–2050 timeframe.
  3. We will update present-day fire emissions at fine-scale resolution across the western United States and also investigate future fire activity following Yue, et al. (2013, 2014, 2015).

Journal Articles on this Report : 3 Displayed | Download in RIS Format

Other project views: All 10 publications 7 publications in selected types All 7 journal articles
Type Citation Project Document Sources
Journal Article Achakulwisut P, Shen L, Mickley LJ. What controls springtime fine dust variability in the western United States? Investigating the 2002–2015 increase in fine dust in the U.S. Southwest. Journal of Geophysical Research: Atmospheres 2017;122(22):12449-12467.
abstract available   full text available
R835875 (2017)
R835875 (2018)
R835875 (2019)
R835875 (Final)
  • Full-text: SemanticScholar-Full Text PDF
  • Abstract: Wiley-Abstract
  • Journal Article Lin M, Horowitz LW, Payton R, Fiore AM, Tonnesen G. US surface ozone trends and extremes from 1980 to 2014: quantifying the roles of rising Asian emissions, domestic controls, wildfires, and climate. Atmospheric Chemistry and Physics 2017;17(4):2943-2970.
    abstract available   full text available
    R835875 (2017)
    R835875 (2019)
    R835875 (Final)
    R835878 (2016)
    R835878 (2017)
    R835878 (2018)
    R835878 (2019)
    R835878 (Final)
  • Abstract: AOS-Abstract
  • Other: ACP-Full Text PDF
  • Journal Article Liu JC, Wilson A, Mickley LJ, Ebisu K, Sulprizio MP, Wang Y, Peng RD, Yue X, Dominici F, Bell ML. Who among the elderly is most vulnerable to exposure to and health risks of fine particulate matter from wildfire smoke? American Journal of Epidemiology 2017;186(6):730-735.
    abstract available   full text available
    R835875 (2017)
    R835875 (2018)
    R835875 (2019)
    R835875 (Final)
    R834798 (Final)
    R835871 (2017)
    R835871 (2018)
    R835871 (2020)
  • Full-text from PubMed
  • Abstract from PubMed
  • Associated PubMed link
  • Full-text: OUP-Full Text HTML
  • Other: OUP-Full Text PDF
  • Supplemental Keywords:

    intercontinental transport, climate change

    Progress and Final Reports:

    Original Abstract
  • 2016 Progress Report
  • 2018 Progress Report
  • 2019 Progress Report
  • Final Report