Health Impacts of Research on Fine
and Ultrafine PM Exposure

This page updated July 17, 2003.


Southern California Particle Center and Supersite-Ambient Aerosol Concentrator and Exposure Facility
  The Southern California Particle Center and Supersite (SCPCS) has undertaken a five-year research activity to develop and implement transportable exposure facility that provides concentrated coarse, fine and ultrafine real-life particles from Los Angeles air basin. These concentrated particle fractions will be used for studies of biological models and to evaluations of cardiopulmonary responses to PM using human volunteers, sensitive animal models and in vitro assays. The research has thus far focused on the following: 1) investigation of biological mechanisms of PM-related health effects, including assessing relationships among physical and chemical characteristics and measurable effect endpoints; 2) emission sources (e.g., freeways) and related adverse health effects; and 3) varying spatial and temporal patterns of PM, including atmospheric chemistry processes and resulting health effects.
  Results suggest that exposure to ultrafines-while very complex-are greatest in the first 300 meters from a major source, with levels decreasing to ambient upwind concentrations at distances greater than 300 meters. Furthermore, in vitro oxidative stress studies were carried out to determine which PM components induce pulmonary inflammation. The results indicated that ultrafine particles (versus fine and coarse particles) were the most potent towards inducing cellular heme oxygenase, an effect which was directly correlated to high organic carbon and PAH content of the ultrafine fraction. Furthermore, morphological examinations of alveolar cells have shown that ultrafine particles localize in mitochondria, where they induce structural damage and contribute to oxidative stress processes.


Ultrafine Particles at the Children's Health Study Air Monitoring Stations
  We have installed condensation particle counters (CPS's) at the 12 air monitoring stations in the Southern California Children's Health Study (CHS). At this time there has been over one year of monitoring at all sites and almost two years at some sites. Results to date indicate significant site-to-site differences dependant on the types of sources near the station, the distance to sources, the degree of influence of long range transport and atmospheric chemical transformations that occur between the source and the monitoring station. Diurnal patterns of particle number concentrations related to the above influences are evident at each station. Meteorology and seasonality also play significant roles.


Scanning Mobility Particle Sizers Project
  Two scanning mobility particle sizers (SMPS's) are circulating throughout the Southern California Children's Health Study (CHS) air monitoring stations. The size profiles at each station contribute to the knowledge about what sources and processes are influencing the air quality at each site. Results indicate variations in both size profiles and total particle number concentrations related to the sources and influences noted in the CHS ultrafine monitoring paragraph.


Fresno Asthmatic Children's Environment Study Ultrafine Monitoring
  Ultrafine monitoring was included in the ambient air monitoring for the Fresno Asthmatic Children's Environment Study (FACES) project. In FACES, two portable air monitoring trailers outfitted with an extensive suite of monitoring equipment, including CPCs, are located at schools in the Fresno and Clovis school districts. At the First Street, fixed air monitoring station ultrafine particles are monitored with an SMPS. Early results indicate large-scale consistencies between schools, but also differences in particle number concentrations and diurnal patterns.


Ultrafine Request for Proposals
  Recent evidence has indicated that ultrafine particles may be a particular concern due to their higher potential to cause detrimental health effects. A request for pre-proposals for studies to examine the health effects of ultrafine particles was sent to the Universities of California. The objective of the request is to determine the health impacts associated with short-term (one to 24-hour time base) exposure to ultrafine particles and other components of California air pollution. The related objective is how these health impacts may be affected by subject vulnerability factors and issues of environmental justice.