Research Projects

Epidemiological studies have demonstrated that respiratory and cardiovascular health effects are most associated with particulate matter (PM) levels one to three days prior to the advent of adverse health responses. However, the temporal patterns for development of pulmonary and cardiovascular responses appear to differ. Little is understood as to whether adverse changes in respiratory and cardiovascular endpoints represent independent effects that have different time courses for development, or whether they represent a continuum of effects that share common biological pathways and are inter-related. In addition, past studies have evaluated all endpoints at the same time post-exposure. Because of this, little is known about the time course for development of respiratory and cardiovascular effects. This project will involve a series of experiments in the Central Valley of California designed to investigate how time lags in exposure increase or diminish pulmonary and cardiovascular responses in a species of mouse model that has similar pulmonary and systemic responses to PM as are observed in humans. The hypothesis of this project is that local pulmonary inflammatory responses in the airways of the lung precedes, and then initiates vascular inflammation and subsequent platelet activation. Platelet activation is a key factor in formation of thrombi (clots) in the systemic circulation, leading to heart attacks and stroke, which are the among the leading causes of premature death that have been associated with PM exposure. The results of this project will provide critical data on the biological mechanisms through which PM adversely impacts health, and will specifically address the key question of the lack of concordance between respiratory and cardiovascular endpoints. This study will provide important information that will help to explain the biological basis of epidemiological associations between adverse health outcomes and PM, and provide needed biological support for state and national ambient air quality standards for PM.