Extreme Air Quality Events Using a Hierarchy of Models: Present and Future

EPA Grant Number: R835205
Title: Extreme Air Quality Events Using a Hierarchy of Models: Present and Future
Investigators: Hess, Peter , Berner, Judith , Grigoriu, Mircea Dan , Mahowald, Natalie M. , Samorodnitsky, Gennady
Current Investigators: Hess, Peter , Berner, Judith , Grigoriu, Mircea Dan , Mahowald, Natalie M.
Institution: Cornell University , National Center for Atmospheric Research
EPA Project Officer: Chung, Serena
Project Period: June 1, 2012 through May 31, 2015 (Extended to May 31, 2016)
Project Amount: $746,825
RFA: Extreme Event Impacts on Air Quality and Water Quality with a Changing Global Climate (2011) RFA Text |  Recipients Lists
Research Category: Air Quality and Air Toxics , Global Climate Change , Water and Watersheds , Climate Change , Air , Water


The sensitivity of mean and extreme pollutant concentrations to changes in emissions and climate is likely to differ. Here we will focus on an evaluation of understanding extreme pollution events under a changing climate. The specific objectives are: (i) develop extreme value models based on measurements and model simulations of the past few decades where frequent measurements are available; (ii) apply extreme value theory to simulations of future climate conditions and future emission scenarios; (iii) investigate the relationship and feedbacks between extreme pollution events and heat waves, and the importance of biomass burning to extreme pollution events; (iv) evaluate the impact of adding stochastic parameterizations to improve model simulations of extreme events; (v) develop surrogate models of extreme events.


The overall analysis approach is grounded in using extreme value theory in conjunction with measurements and models of ozone and aerosols over the U.S. The proposed research is interdisciplinary and innovative, combining extreme value theory, stochastic modeling and state-of-the-art atmospheric chemistry climate and earth system modeling. Extreme value theory will be applied to (i) measurements; (ii) simulations using a chemical transport model (CTM) based on analyzed meteorological winds and (iii) simulations using the Community Earth System Model (CESM) based on predicted winds. The CTM and CESM will aJso be used: (i) to interpret the impacts of changing emissions and meteorology on the application of extreme value theory to the measurements in the current climate; (ii) to extend the results so as to apply extreme value theory to future emission and climate change scenarios.

Expected Results:

The outcome of this work will provide insights to the air-quality planning community on the probability, frequency, duration, and severity of high pollution episodes over the U.S. in relation to changes in emissions and climate. In particular, we will: (i) provide information on the geographic, meteorological, climatological, and chemical conditions that contribute to extreme pollution episodes in the U.S.; (ii) enhance current air quality models to better capture changes in extreme pollution events in different regions of the country.

Publications and Presentations:

Publications have been submitted on this project: View all 22 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 10 journal articles for this project

Supplemental Keywords:

Global climate, CASTNET, Environmental Chemistry, Statistics, General circulation models,

Progress and Final Reports:

  • 2012 Progress Report
  • 2013 Progress Report
  • 2014 Progress Report
  • Final Report