The extent to which individuals in different communities
are aware of air quality indices or alerts has varied greatly
in surveys and focus groups conducted in the US, Canada,
and UK (28). There is little data on the extent to which
individuals change behavior to reduce exposure either in
response to air quality data or perceptions of exposure. In
a study of Portland and Houston in the US in 2005-2006,
a third of 1,962 participants were aware of air quality
alerts, but only 10-15% of individuals reported changing
behavior in response to predicted poor air quality, and cited
perceptions of poor air quality as driving their behavior,
not official advisories (34). Similarly, in a cross-sectional
study of 33,888 adult participants, in six states, in the 2005
Behavioral Risk Factor Surveillance System (BRFSS),
about a third of adults with asthma and 16% without
asthma reported change in outdoor activity due to media
alerts (35). Individual perception of poor air quality and
health professional advice greatly increased the prevalence
of reported behavior change. We could find no studies
that have assessed associations between health outcomes