Research Projects

Current National Ambient Air Quality Standards for particulate matter regulate the mass concentration of particles in the atmosphere. There is growing evidence that different sources of these particles have different levels of toxicity. In this work, a system was developed for collecting source oriented particles from the atmosphere suitable for toxicity testing, as described in Chapter 2 of this report. Briefly a single particle mass spectrometer identified particle sources in real time; the mass spectrometer selected a ChemVol associated with each source category to collect size-selected PM while those particles were being observed. This system was operated in Fresno, CA during the summer of 2008 and winter of 2009. The toxicity of the collected samples was assessed in a mouse model. Samples were chemically analyzed to associate them with sources prevalent in Fresno, CA. Most of the toxicity was associated with automobile and cooking sources in both seasons while in the winter toxicity was also associated with secondary compounds.