The objective of the Children's Health Study is to determine whether long-term exposure to ambient ozone, PM, NO2, and strong acid vapor is responsible for chronic respiratory problems in children in Southern California. STI scientists are co-principal investigators in the study. We are responsible for the exposure assessment element of the study and are involved in all phases of this 11-year project in 12 communities, in collaboration with the USC Keck School of Medicine. STI staff helped design the study and implement the air monitoring network. The children's exposure to air pollution is assessed through ambient monitoring, personal sampling, residential monitoring, school-based monitoring, time-activity surveys, housing questionnaires, and exposure modeling. Special projects include neighborhood-scale modeling of the children's exposure to on-road mobile source emissions. STI staff quality assure all of the exposure-related data used in the study and perform statistical analysis of the temporal and spatial characteristics of the ambient pollution levels in the 12 communities. STI staff have co-authored many of the 27 peer-reviewed publications generated from this ongoing study. This study is sponsored by the California Air Resources Board.
The Fresno Asthmatic Children's Environment Study (FACES), sponsored by the California Air Resources Board and the U.S. EPA, is designed to analyze the effects of air pollution on asthmatic children aged 6 to 14 years living in Fresno, California. A group of 450 asthmatic children are being monitored from 2001 to 2005 to evaluate the effects of daily air pollution levels on short-term asthma, to assess the influence of short-term asthma exacerbation on the progression of childhood asthma over the course of several years, and to evaluate the extent to which other environmental factors, such as tobacco smoke, allergens and other bioaerosols, and housing characteristics influence asthmatic children's response to air pollution. STI scientists are co-investigators of the study and are primarily responsible for the exposure assessment element. We are involved in the study design, ambient air quality measurements, housing and time-activity surveys, residential and school air pollution sampling, exposure data quality assurance, and exposure modeling. In addition to providing oversight for all of the exposure-related measurements, we conducted a one-year intensive sampling program where indoor and outdoor measurements of particulate matter mass and chemical constituents, nitrogen dioxide, ozone, polycyclic aromatic hydrocarbons, endotoxins, pollens, spores, and environmental tobacco smoke will be measured in the participants' homes. Mobile vans will provide detailed exposure information for schools. Exposure models will be developed to estimate the daily exposure of children in the study.
The study assessed the relationship between air pollution and the occurrence of acute respiratory and chronic cardiovascular morbidity and mortality among members of a California managed care organization. STI scientists were co-investigators of the study, with primary responsibility for the retrospective exposure assessment. Ambient ozone, NO2, CO, and PM10 air quality data and meteorological data were spatially mapped to estimate the daily exposures of the members for 1988 through 1999. Missing HiVOL-equivalent PM10 values were estimated from regression models utilizing continuous coefficient of haze data, PM10 TEOM data, and PM10 BAM data. A case-crossover approach was used to estimate the risk of cardiovascular related hospitalization associated with exposure to ambient air pollution. Cases were defined as members of the base population who were hospitalized with a discharge diagnosis of selected cardiovascular conditions (n=20,900). Exposure was assigned to each individual based on his or her residential address. A significant trend was observed between PM10 and cardiovascular disease (CVD) hospitalizations where the risk increased with increasing exposure level. The results also suggest having no prior hospitalization history with CVD had more risk than having such a history.