1. A Decision Framework for Vehicle Inspection and Maintenance Programs Using Health Benefit Analysis Ying Li University of North Carolina at Chapel Hill, Departments of Public Policy and Institute for the Environment liying@email.unc.edu RESULTS (Contd.) FIG 3. Annual Health Benefits and Costs of I/M Programs as a Function of Vehicle Emission Reduced (Year: 2008) FIG 4. The Effect of Uncertainty in Emission Reduction on Total Annual Health Benefits Associated with I/M Programs (Year: 2008) Discussion  Particle-related vehicle I/M programs may substantially improve public health particularly in heavily polluted urban areas.  The total health benefits of I/M programs are the most sensitive to the levels of emission reduction achieved by I/M. In the case of Bangkok, a minimum of about 5% reduction in total vehicle PM 10 emissions is required to ensure the net benefits of the programs are positive. FIG 1. Mathematical Modeling Steps ABSTRACT Motor vehicle inspection and maintenance (I/M) programs have been considered cost-effective for the control of air pollution particularly in heavily polluted urban areas where vehicles are responsible for a substantial fraction of total emissions. The primary benefits of I/M programs are generally measured as the public health improvement attributable to reductions in air pollution. On the other hand, past practices in the U.S. and elsewhere demonstrate that the design and implementation of I/M programs often involves many challenges, and the actual effects of this policy tool can be highly uncertain. However, this uncertainty issue has traditionally been ignored in the cost-benefit analysis of I/M programs. This study develops a decision framework that links the emission reduction levels of I/M programs to the associated health benefits to help policymakers to determine whether the investment of social resources required for an I/M program are beneficial and to make decision about improving I/M program design. This framework also forms the basis of an improved cost-benefit analysis of I/M programs that takes into account the key uncertainty about the actual effects of the programs. Using this framework, a case study is conducted in Bangkok, Thailand to evaluate the health benefits of a proposed particulate matter (PM 10 ) related I/M system targeting diesel-fueled vehicles and motorcycles in this mega-city where particle pollution has been a serious concern for several decades. INTRODUCTION  Air pollutant of concern: Fine particles having an aerodynamic diameter of less than or equal to 10 micrometers, or PM 10. It is considered as the air pollutant of the greatest health impacts because scientific studies consistently found that fine particles are responsible for the largest fraction of mortalities due to air pollution exposure and they also cause a series of morbidity effects such as respiratory and cardiovascular diseases.  Mobile sources of PM 10 : In urban areas, motor vehicles can contribute to a substantial fraction of total PM 10 emissions. Particles can be emitted from certain types of vehicles such as diesel-fueled vehicles, or can be formed from other compounds in vehicle exhaust.  Policy tool of focus: Vehicle inspection and maintenance (I/M) programs. Through periodic testing to identify high-polluting vehicles, an I/M program aims at assuring that vehicle emission control systems are functioning properly throughout the lifetime of the vehicle. Traditional I/M programs focus primarily on gasoline-fueled vehicles, but there is an growing interest to introduce equivalent programs for diesel vehicles due to the health threats posed by diesel exhaust.  The case of Bangkok: Thailand: Over the past decade, severe PM 10 pollution problem has caused enormous economic loss in this populous metropolitan area. Air pollution caused by rapidly growing motor vehicles, in particular by diesel vehicles and motorcycles, is the most salient issue.  Study objectives: Estimating health benefits associated with particle- related I/M programs in developing countries and developing a decision framework that takes into account the uncertainty about policy effects. METHODS  Health Benefit Analysis: An integrated approach ACKNOWLEDGEMENTS This work was financially supported by Institute for the Environment and advised by Professor Douglas J. Crawford-Brown, University of North Carolina at Chapel Hill. Air quality data were provided by Pollution Control Department of Thailand. METHODS (Contd.) Table 1 Health Endpoints Included and Selected Exposure-Response Functions FIG 2. Distribution of Mobile Particulate Matter Emission Sources in Bangkok, Thailand (Projected Emission Reduction Levels in Parentheses) Key Modeling Steps (Contd.)  Health endpoints considered: Both mortality and morbidity (Table 1).  Exposure-response functions: Abstracting from the literature; selecting studies conducted in Thailand or other Asian countries wherever possible (Table 1).  Health impact function: y: number of cases; Beta: health risk coefficient; x: PM 10 ambient concentrations.  Economic valuation: Willingness-to-Pay (WTP) v.s. Cost-of-Illness (COI): WTP is the most appropriate valuation method; in the absence of WTP, COI can be used with reasonable adjustment. Due to the lack of data in Thailand, data in the U.S. is used assuming that WTP is proportional to income and the income elasticity of WTP is 0.4. Key Modeling Steps  Simulating ambient PM 10 levels: Simple proportional model.  Mobile sources’ contribution to total PM 10 emissions: mean estimate -- 38.3%.  Human exposure assessment: Using ambient concentrations as the surrogate of personal exposure. RESULTS  Health damage in Bangkok attributable to PM 10 from motor vehicle sources in the baseline year 2000 was about 1873 million 2000 U.S. dollars.  Under the business-as-usual scenario (no control policy), PM 10 emissions from motor vehicles in 2008 are forecasted to be more than double the total emissions in the baseline year due to the rapid growth in vehicle population, and consequently the health damage due to traffic-related fine particles is estimated to be 4132 million 2000 U.S. dollars in 2008.  A fully effective I/M system targeting all diesel-fueled vehicles and motorcycles in Bangkok is projected to reduce PM 10 emissions from mobile sources by 25%, and achieve health benefits of about 933 million 2000 U.S.$.  On the other hand, total annual health benefits associated with I/M programs are very sensitive to the levels of PM 10 emissions reduced (FIG. 3 and FIG. 4). Uncertainty analysis using Monte Carlo sampling method indicates that the uncertainty about emission reduction contributes the most (76.6%) to the overall uncertainty.  Costs of an I/M program usually include start-up costs (e.g. equipment cost, land cost, etc) and testing costs (e.g. operating cost, maintenance cost, etc). The total annual cost of the particle I/M programs in Bangkok is estimated to be about 164 million 2000 U.S. dollars, and is considered not to vary significantly once the programs are launched, and to be independent of the levels of emission reduction.