Specifications include, but are not limited to: The objective of this research is to evaluate the health impacts associated with particulate matter (PM) 2.5 exposure, and shall include heath endpoints that evaluate work loss days and/or days of restricted activity or asthma exacerbations. Proposals that evaluate work loss days and/or restricted activity days are preferred over studies on asthma exacerbations. The outcome from this study will inform the California Air Resources Board’s (CARB and State) health impacts calculations for PM2.5, which are used to quantitatively evaluate the benefits of proposed regulations. New research on work loss days and asthma exacerbations associated with PM2.5 will improve CARB’s capacity to capture the projected health benefits of public policies.