How effective are air quality alerts in reducing adverse effects in the real world?

For air quality advisories to have a positive effect on public health, they must be widely available and well-understood. Evidence indicates the AQI may indeed be helpful. Data from the 2005 Behavioral Risk Factor Surveillance System (BRFSS) conducted in six states (Colorado, Florida, Indiana, Kansas, Massachusetts, and Wisconsin) were analyzed to assess reductions or changes in outdoor activities because of media alerts on AQI and health professional advice to reduce or change outdoor activity levels (Wen et al., 2009). BRFSS is a standardized state-based telephone survey system designed to collect data on health risk behaviors and health conditions from adults aged 18 and older. About 31% (95% CI: 27.8–34.4%; P < 0.0001) of the respondents with lifetime asthma and 16% (95% CI: 15.1–17.1%; P < 0.0001) of those without asthma reported changes in outdoor activities because of media alerts of air quality. Among the respondents who ever received a health professional’s advice to reduce outdoor activity, about 51% of those without asthma (95% CI: 43.2–57.9%; P < 0.001) and 57% of those with lifetime asthma (95% CI: 49.1–63.7%; P < 0.001) reported a media alert-based outdoor activity change or reduction. This shows that receiving advice from a health professional is also a very important factor in the decision to change or reduce outdoor activities.

An activity diary study (Mansfield et al., 2006) found that parents of children with asthma were more likely to report checking the AQI frequently, with more serious asthma being a predictor of more frequent checking. The activity diaries revealed that parents who thought that their asthmatic children were sensitive to air pollution reduced their children’s time outdoors by about 30 minutes on a “Code Red” day relative to a non-Code Red day. On days with Good (Green) air quality, the amount time spent outdoors was similar for asthmatic children who were believed to be sensitive and non-sensitive to air pollution.

A 2009 paper (Neidell and Kinney 2009) estimates the statistical association between ambient ozone concentrations and asthma hospitalizations in Southern California while accounting for potential avoidance behavior in response to forecasted air quality. Data on asthma hospital admissions were merged with observed and forecasted air quality and meteorological data at the daily level for the years 1989–1997. Accounting for potential responses to information about pollution leads to significantly larger estimates of the relationship between ozone concentrations and asthma hospital admissions, particularly for susceptible populations. Individuals take substantial actions to reduce exposure to ozone.

Where can the daily AQI be found?

In many areas, the local media - newspapers, television and radio - will provide AQI reports telling the public when ozone levels are predicted to be unhealthy. These reports generally occur during the weather forecasts. Some national media, such as USA Today, The Weather Channel, and CNN also provide daily air quality reports.

Air quality forecasts and real-time air quality information can be found on EPA's AIRNow Web site (www.airnow.gov). Ozone air quality forecasts for more than 350 cities across the country are posted daily by 4:30 PM during the summertime ozone season.

Click here for today's air quality forecast.