Article
Missing the Warning Signs? The Case of "Yellow Air Day" Advisories in Northern Utah
Environmental and Resource Economics
(2023)
Abstract
Using a dataset consisting of daily vehicle trips, PM2.5 concentrations, and a host of climac-
tic control variables, we test the hypothesis that “yellow air day advisories” issued by the
Utah Division of Air Quality resulted in subsequent reductions in vehicle trips taken dur-
ing northern Utah’s winter-inversion seasons in the early 2000 s. Winter inversions occur in
northern Utah when PM2.5 concentrations (derived mainly from vehicle emissions) become
trapped in the lower atmosphere, leading to unhealthy air quality over a span of time known
colloquially as “red air day episodes”. When concentrations rise above 15 μg∕m3 toward the
National Ambient Air Quality Standard average daily threshold of 35 μg∕m3 , residents are
informed via different media sources and road signage that the region is experiencing a yel-
low air day, and are urged to reduce their vehicle usage during the day. Our results suggest
that the advisories have provided at best weak, at worst perverse, incentives for reducing
vehicle usage on yellow air days and ultimately for mitigating the occurrence of red air day
episodes during northern Utah’s winter inversion seasons.
Disciplines
Publication Date
2023
Citation Information
Arthur Caplan. "Missing the Warning Signs? The Case of "Yellow Air Day" Advisories in Northern Utah" Environmental and Resource Economics (2023) Available at: http://works.bepress.com/arthur_caplan/152/