Public Health Air Surveillance Evaluation Project Team (PHASE)
: Because of the problems inherent in measuring air quality, particularly the lack of air quality monitors, the Public Health Air Surveillance Evaluation project team developed an innovative strategy to model air quality. Researchers used the model output to estimate peak fine particulate matter and ozone concentrations for each day in the year and, using National Ambient Air Quality Standards, estimate the number of days that the air quality was poor for sensitive populations due to these contaminants.
: Centers for Disease Control and Prevention and Environmental Protection Agency (CDC and EPA)
Data Years Available
: Modeled data.
: Annual number of days that air quality was unhealthy for sensitive populations due to fine particulate matter and ozone concentrations.
: All counties in continental U.S.
: The Environmental Protection Agency's (EPA) first step to address insufficient data collection sites was the creation of an air quality simulation model, the Community Multi-Scale Air Quality Model (CMAQ). To improve upon CMAQ, the PHASE project uses both CMAQ output and monitor data in a hierarchical spatial-temporal model to estimate daily ozone and fine particulate matter concentrations throughout the year
Response rate and sample size
: Data are provided on only two contaminants. Though fine particulate matter and ozone are commonly viewed as two of the pollutants most harmful to health, the PHASE estimates do not provide any measure of cancer risk or respiratory hazard due to other criteria contaminants.