The impact of an air quality advisory program on voluntary mobile source air pollution reduction

Air pollution from mobile source emissions is a major cause of air quality degradation in the Denver, Colorado, metropolitan area. The projected incre ase in both population and vehicle miles driven, coupled with the high alti tude, predominantly clear skies, and prevalent wintertime temperature inver sions aid in the formation and retention of pollutants. The Colorado Depart ment of Public Health issues an air quality advisory daily during the high pollution season (November 1-March 31) with the objective of improving air quality through voluntary driving restrictions and a mandatory wood burning ban. We hypothesized that the advisory had no effect on commuter behavior due to lack of awareness and understanding, lack of alternative means of tr avel, or lack of concern. We mailed an anonymous, self-administered survey to 1000 commuters living in the cities of Boulder and Westminster, Colorado . Despite the fact that the vast majority of the respondents were aware of the daily advisory (94%), understood what it meant (93%), and heard the pos ting at least once a day (71%) in time to choose alternative forms of trans portation, the advisory did not alter commuter travel. Commuters traveled m ainly as the sole occupant of a car and most (76%) never changed the way th ey commuted based on the daily advisory. Many claimed schedules or work loc ations did not allow them to use alternative transportation methods. We sug gested a practical way to improve the advisory would be to reduce or elimin ate public transit fares on poor air quality days. (C) 2001 Elsevier Scienc e Ltd. All rights reserved.