Fine and Ultrafine Particulate Matter Research

This page updated July 17, 2003.

Particulate Matter (PM) is currently regulated as a criteria pollutant under both California and Federal Ambient Air Quality Standards (AAQS). However, recent concerns of known or potential adverse health effects associated with exposure to the smaller size fractions of PM-especially the fine (0   2.5 micrometers aerodynamic diameter) and ultrafine (less than 0.1 micrometers aerodynamic diameter) size ranges-have generated considerable activity in the research community. The Research Division is involved with numerous projects related to this important area of ongoing research.

Health Effects Related PM Research

As health effect research continues to explore the relationships between exposure to PM and adverse health outcomes, the question inevitably arises as to the what aspects of PM are inherently more toxic. Research activity has increased due to the need to address this issue, and researchers are focusing on studies designed to look at PM size, composition and toxicological mechanisms of effect. The ARB's Research Division sponsors multiple studies that contain aspects related to fine and ultrafine PM and associated toxic effects or related adverse health effects. These studies are summarized below:

Summaries of Research for Fine and Ultrafine PM.

Physical-Chemical Characteristics Related Research

Understanding the physical and chemical characteristics of PM-including fine and ultrafine sub-fractions is of considerable interest from a health effects and air pollution control perspective. In addition, identifying sources and improving methods of measurement and analysis of the smallest size fractions is extremely important as research focuses on the toxicity and associated adverse health effects related to composition and size of PM. The Research Division sponsors multiple studies that contain aspects related to the physical and chemical characteristics of fine and ultrafine PM, their sources in California, and their methods of analysis. These studies are summarized below:

Physical and Chemical Summaries for Fine and Ultrafine PM.

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