Incentive programs for scrapping old, high-emitting vehicles have been implemented to reduce air pollutants and greenhouse gases, but these policies also may create additional sales of new vehicles. From a life cycle perspective, the emissions from both the additional vehicle production and scrapping need to be addressed when evaluating the benefits of scrapping programs. This study explores an optimal fleet conversion policy based on mid-sized internal combustion engines. An optimal policy would minimize total life cycle emissions from the entire fleet of new and used vehicles. To describe vehicles' lifetime emission profiles as functions of accumulated mileage, a series of life cycle inventories characterizing environmental performance for vehicle production, use and retirement was developed for each model year between 1981 and 2020. A simulation program was developed to investigate ideal and practical fleet conversion policies separately for three regulated pollutants (carbon monoxide, non-methane hydrocarbons, oxides of nitrogen) and for carbon dioxide. According to the simulation results, accelerated scrapping policies are effective in reducing regulated emissions, but they may slightly increase greenhouse gases. Retaining the current fleet age distribution appears to be the optimal policy from the standpoint of carbon dioxide emissions. Multi-objective analysis based on economic valuation methods was used to investigate trade-offs among emissions of different pollutants. Optimal fleet conversion strategies are dependent on the relative importance of each pollutant, and estimated damage and control costs for different pollutants vary with several factors. Thus, each accelerated scrapping program should be carefully designed based on the target pollutants of the program.

Optimal fleet conversion policy from a life cycle perspective

https://faculty.uml.edu/tsloan/papers/Sloan-JCP-v19n2-3-2011.pdf

Green renewal: incorporating environmental factors in equipment replacement decisions under technological change

Shaping sustainable vehicle fleet conversion policies based on life cycle optimization and risk analysis.

Two general methods of estimating monetary values of air pollutants are presented in this paper. The damage estimate method directly estimated, air pollutant by simulating air quality, identifying health and other welfare impacts damage values and valuing the identified impacts of air pollution, and valuing the identified impacts. Although the method is theoretically sound, many assumptions are involved in each of its estimation steps, and uncertainty exists in each step. The control cost estimate method estimates the marginal emission control cost, which represents the opportunity cost offset by emission reductions from some given control measures. Studies conducted to estimate emission values in US regions used either the damage estimate method or the control cost estimate method. Taking emission values estimated for some US air basins, this paper establishes regression relationships between emission values and total population and air pollutant concentrations. On the basis of the established relationships, both damage-based and control-cost-based emission values are estimated for 17 major US urban areas.

D.J. Santini

Papers

Estimation of monetary values of air pollutant emissions in various US areas