Student Research: Eva Dale

, Environmental Toxicology (Tox), 2004
Faculty Advisor: Jane Q. Koenig

Effect of PM2.5 on Exhaled Nitric Oxide: An Intervention Field Study


Adverse health effects consistently are reported to be associated with particulate matter (PM) air pollution. Two research needs in this area are 1) to identity mechanisms of action of particulate matter and 2) to identify exactly whether it is particulate matter or gaseous pollutants hat is the more toxic component of air pollution. Exhaled nitric oxide (eNO) is a reproducible, non-invasive indicator of airway inflammation, thus may offer opportunities to carry out more mechanistic studies in the field. Exposure to PM2.5 (particulate matter less than or equal to 2.5 micrometers in diameter) has been shown to be associated with an increase in eNO levels in children with asthma and adults with respiratory disease. However, an association of increased eNO values with PM2.5 is the responsible agent. The responsible agent may be a pollutant that is highly correlated with PM2.5. It has also been shown that approximately 79% of ambient PM2.5, on average, infiltrates into homes unless an electrostatic precipitator is used. High-Efficiency Particulate Air (HEPA) filters remove an average of 99.7% of air-borne particles equal to 0.3 micrometers in diameter that pass through the device. HEPA devices without charcoal prefilters do not filter out gases. This study attempted to provide improved interpretation of the role of fine particles verses outdoor gaseous pollutants in the up-regulation of airway nitric oxide. The hypothesis of this study was that a decrease in daily exposure to PM2.5, through intermittent use of a HEPA filter, would be associated with a decrease in daily exhaled nitric oxide in elderly subjects with respiratory disease.

Taken from the beginning of thesis.