Air quality warnings and outdoor activities: evidence from Southern California using a regression discontinuity
1Department of Health Policy and Management, Columbia University, 600 W. 168th Street, 6th Floor, New York, NY 10032, USA. mn2191@columbia.edu
Background:
A study was undertaken to assess the impact of air quality warnings associated with ground-level ozone on outdoor activities in Southern California.
Methods:
Data on aggregate daily attendance at two major outdoor facilities were collected and merged with observed and forecasted air quality and meteorology at the daily level. A quasi-experimental regression discontinuity design was used to estimate the impact of warnings.
Results:
Attendance declined significantly when stage 1 air quality warnings ('smog alerts') were issued. Consistent with expectations, responses were greater for populations more likely to be considered susceptible and more likely to be local residents.
Conclusions:
Air quality warnings are an important policy tool for protecting the public's health from high levels of ambient air pollution.
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