Abstract
Abstract. The effect of climate change on population-weighted concentrations of particulate matter (PM) during extreme pollution events was studied using the Parallel Climate Model (PCM), the Weather Research and Forecasting (WRF) model and the UCD/CIT 3-D photochemical air quality model. A "business as usual" (B06.44) global emissions scenario was dynamically downscaled for the entire state of California between the years 2000–2006 and 2047–2053. Air quality simulations were carried out for 1008 days in each of the present-day and future climate conditions using year-2000 emissions. Population-weighted concentrations of PM0.1, PM2.5, and PM10 total mass, components species, and primary source contributions were calculated for California and three air basins: the Sacramento Valley air basin (SV), the San Joaquin Valley air basin (SJV) and the South Coast Air Basin (SoCAB). Results over annual-average periods were contrasted with extreme events. The current study found that the change in annual-average population-weighted PM2.5 mass concentrations due to climate change between 2000 vs. 2050 within any major sub-region in California was not statistically significant. However, climate change did alter the annual-average composition of the airborne particles in the SoCAB, with notable reductions of elemental carbon (EC; −3%) and organic carbon (OC; −3%) due to increased annual-average wind speeds that diluted primary concentrations from gasoline combustion (−3%) and food cooking (−4%). In contrast, climate change caused significant increases in population-weighted PM2.5 mass concentrations in central California during extreme events. The maximum 24-h average PM2.5 concentration experienced by an average person during a ten-yr period in the SJV increased by 21% due to enhanced production of secondary particulate matter (manifested as NH4NO3). In general, climate change caused increased stagnation during future extreme pollution events, leading to higher exposure to diesel engines particles (+32%) and wood combustion particles (+14%) when averaging across the population of the entire state. Enhanced stagnation also isolated populations from distant sources such as shipping (−61%) during extreme events. The combination of these factors altered the statewide population-averaged composition of particles during extreme events, with EC increasing by 23 %, nitrate increasing by 58%, and sulfate decreasing by 46%.
Highlights
Air pollution is a persistent public health problem in the United States with over 158 million people living in regions that violate the National Ambient Air Quality Standards (NAAQS) (USEPA, 2008)
The current study found that the change in annual-average population-weighted PM2.5 mass concentrations due to climate change between 2000 vs. 2050 within any major subregion in California was not statistically significant
Epidemiological studies have estimated rates of mortality and morbidity associated with PM2.5 yielding predictions that an average of 24000 people die from exposure to particulate matter each year in the United States (Mokdad et al, 2005)
Summary
Air pollution is a persistent public health problem in the United States with over 158 million people living in regions that violate the National Ambient Air Quality Standards (NAAQS) (USEPA, 2008). Epidemiological studies have estimated rates of mortality and morbidity associated with PM2.5 (see for example, Samet et al, 2000; Dockery et al, 1993; Pope III et al, 1995) yielding predictions that an average of 24000 people die from exposure to particulate matter each year in the United States (Mokdad et al, 2005). The South Coast Air Basin (SoCAB) has ∼15 million residents that experience 24-h average PM2.5 concentrations that are up to ∼2.3 times higher. The San Joaquin Valley (SJV) has ∼3 million residents that experience 24-h average PM2.5 concentrations that exceed the NAAQS by a factor of ∼2.3
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
