Detection of metals in ambient particulate matter with aerosol mass spectrometry

Exposure to ambient particulate matter (PM) contributes to about 100,000 premature deaths in the U.S. each year. While the dose-response relationship is well characterized, the component(s) of PM that drive ill health effects are unknown. One hypothesis is that metals present in PM induce oxidative stress that harms health.

The aerosol mass spectrometer (AMS) is an instrument that characterizes PM size and composition in real time. It uses a heated surface to evaporate PM; vapors are ionized by electron impact and characterized with a high-resolution mass spectrometer. The mass spectrometer is capable of separating isobaric ions (ions with the same nominal atomic weight), which means that ions with a variety of elemental compositions can be separated and identified.

This project will identify the presence and concentration of several metals in PM samples collected by AMS in Pittsburgh. The student will start with data collected on CMU campus. If metals are present in detectable concentrations, the analysis will progress to consider AMS data collected with a mobile laboratory. The project will develop data analysis skills and expose students to mass spectrometry and atmospheric chemistry.