Research Projects

Project at a Glance

Title: Risk of pediatric asthma morbidity from multipollutant exposures

Principal Investigator / Author(s): Delfino, Ralph and Michael Kleeman

Contractor: UC Irvine

Contract Number: 10-319

Research Program Area: Health & Exposure

Topic Areas: Health Effects of Air Pollution, Vulnerable Populations


One of the Air Resources Boardís (ARB) goals is the protection of sensitive populations, such as children, from air pollution impacts. Numerous studies have shown a link between particulate matter (PM) exposure and asthma morbidity outcomes in children. While these studies have contributed to our understanding of the health impacts of particle exposure in children, several issues regarding the biologically active components of PM remain to be addressed. For example, there is limited information on the health effects of two important classes of particles in California, primary organic aerosols (POA) directly emitted from combustion sources; and secondary organic aerosols (SOA), which are largely photochemically-produced. Moreover, these classes of organic aerosols have different spatial and temporal variability and they are minimally correlated with each other in southern California (Delfino et al 2009b, 2010a, 2010b). The proposed study aims to analyze the possible relationship between asthma morbidity using hospital data for 7,954 children with asthma, and both regional and local exposures to PM including POA and SOA. This will be studied using PM predictions (size-resolved mass, speciation and source apportionment) generated by regional air quality models. PM will be estimated for three particle sizes, including ultrafine (UFP), PM2.5, and PM10, along with estimates of the contributions of specific sources of PM (e.g. diesel, gasoline and wood smoke). Other air pollutants such as ozone (O3), nitrogen oxides (NO2 and NOX) and carbon monoxide (CO) will also be estimated. The study will evaluate whether temporal and spatial variations of PM2.5 sources and species affect the association between PM2.5 mass concentrations and emergency department visits and hospital admissions for asthma. It will also evaluate the association between air pollution susceptibility, including asthma recurrence and socioeconomic status and demographic factors. The present study will leverage the daily POA and SOA exposure data from the University of California, Davis/California Institute of Technology (UCD/CIT) Source Oriented Chemical Transport Model. The proposed study is expected to provide new information on the association of asthma morbidity with multiple local and regional air pollutants and general particle composition. Findings will be relevant to efforts by ARB to control PM2.5 by assessing the importance of sources and components that are related to health outcomes.


For questions regarding research reports, contact: Heather Choi at (916) 322-3893

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