Automobile air emissions are a well-recognized problem and have been subject to considerable regulation. An increasing concern for greenhouse gas emissions draws additional considerations to the externalities of personal vehicle travel. This paper provides estimates of the costs for automobile air emissions for 86 U.S. metropolitan areas based on county-specific external air emission morbidity, mortality, and environmental costs.
Total air emission costs in the urban areas are estimated to be 145 million/day, with Los Angeles, California, and New York City (each 23 million per day) having the highest totals. These external costs average 0.64 per day per person and0.03 per vehicle mile traveled. Total air emission cost solely due to traffic congestion for the same 86 U.S. metropolitan areas was also estimated to be $24 million per day. These estimates are compared with others in the literature and are found to be generally consistent. These external automobile air emission costs are important for social benefit and cost assessment of transportation measures to reduce vehicle use. However, this study does not include any abatement costs associated with automobile emission controls or government investments to reduce emissions such as traffic signal setting.