Abstract:
The primary objetives of this study were to use a mail survey to assess the general public's perceptions of regional air quality issues and to estimate their valuation expressed as willingness to pay (WTP) for a series of hypothetical air quality and visibility programs. A key feature of this survey was that it asked respondents to separate their total WTP for the programs into components for perceived health benefits, visibility benefits and other environmental benefits. The adjusted results of the survey indicate annual household WTP values of 23.0 and 31.2 dollars for programs guaranteeing 20 to 40 percent increases in good visibility days respectively. Marginal WTP was found to decrease rapidly as the number of good visibility days in the programs offered was increased. For air quality programs guaranteeing 50 to 100 percent decreases in days rated as unhealthy using the Pollutant Standard Index the adjusted public annual household WTP was found to be 65.4 and 120.8 dollars respectively. It was observed that the context in which visibility valuation was assessed had a significant affect on WTP values. Assuming that annual household WTP represents annual benefits for visibility and air quality programs, these results indicate that the total benefits to the four eastern counties of central Puget Sound region from a visibility program delivering a 40 percent increase in good visibility days would be 133 million dollars annually. A slope index used in visibility valuation studies relating WTP to the natural logarithm of the fracitonal improvement in visibility was calculated to be 232 to 324 dollars for this study versus an average of 170 dollars for previous studies. An air quality program that decreased unhealthy air quality days by 100 percent resulted in benefits of 118 milliion dollars annually for the region and 140 million if visibility benefits were also included. Using literature based numbers for the values of a saved statistical life and visibility benefits the same air quality program was estimated to result in societal benefits of 587 to 667 million dollars annually for the region