Receptor modeling assessment of particle total exposure assessment methodology data

Data from the 1991 Particle Total Exposure Assessment Methodology (PTEAM) study in Riverside, CA, were analyzed using a new receptor modeling method. In this study, ambient (outdoor), indoor, and personal particulate matter (PM) concentrations and elemental concentrations of PM2.5 and PM10 were measured for a number of participants. These measurements made it possible to relate the pollution to which people were exposed throughout their daily activities with the outdoor air conditions. Personal daytime concentrations of the PM10 and majority of elements were significantly higher than outdoor or indoor concentrations, suggesting that a significant part of personal aerosol exposure is the result of personal daily activities. Possible sources of additional particulate mass include resuspension of particles that penetrate from the outdoors and formation of new particles during cooking, smoking, etc. Positive matrix factorization analysis was performed to describe the sources of personal exposure. To identify relative contribution of different sources, regression of the particulate matter mass against the factor contributions was performed. Major sources of PM2.5 were oil combustion, nonferrous metal operations, and motor vehicles. The mass contributions of particles from these sources were similar for outdoor air and personal exposure. Personal exposure to particles from these sources can be controlled by changing outdoor sources. The primary source of PM10 was soil. Concentrations of outdoor, indoor, and resuspended soil particles have different time dependencies. Sea-salt was a significant source only of outdoor coarse particles. A source profile of aerosols formed by personal activities such as cooking and smoking was identified. Good agreement was found between reported daily activities (smoking, cooking, vacuuming) and the related source contribution estimates.