Measuring the effectiveness of the Air Quality Index: Two web-based studies

Governments and other organizations provide information about environmental risks to the public to help people avoid exposure to pollutants. The Air Quality Index (AQI) is one such program, providing air pollution forecasts (primarily ozone and particulate matter) and advice on avoiding exposure and reducing emissions through media outlets in large cities on a daily basis. This study provides evidence on the effectiveness of the AQI warnings from two surveys conducted using web panels – a survey of children with asthma and a survey of adults age 55 and older. Both studies use activity diaries administered on high and low ozone pollution days to assess whether the children or older adults change their behavior on high ozone days. A debriefing survey collects additional data on awareness of the AQI, risk perceptions about air pollution, and reported behavior on high ozone days. The study of children (funded by an EPA grant and conducted in the summer of 2002) found that children with asthma did reduce their time outdoors on high ozone days and the reductions were correlated with risk perceptions, but not with general awareness of the AQI or parents' reports that they kept their child indoors. EPA's Office of Air Quality Planning and Standards will administer the National-Scale Activity Survey (N-SAS) to study older adults' behavior during summer 2008. N-SAS will be compared with the findings from the children's study. Both studies provide data needed to assess and improve information programs for accountability initiatives, regulatory analysis and successful outreach.