Improving urban air quality in South Asia by reducing emissions from two-stroke engine vehicles

While vehicular air pollution is common to growing metropolitan areas throughout the world, it is particularly severe in South Asia, where about half of all vehicles are two- and three-wheel vehicles with two-stroke engines. This report analyzes different technical and policy options for reducing emissions from two-stroke engines. Precisely because two-stroke engine vehicles are so numerous and popular, a policy decision to address emissions from these vehicles must take into account the socioeconomic consequences of such a decision. While a large-scale immediate ban on gasoline-powered two-stroke engine vehicles would be extremely difficult and costly, numerous small and cost-effective improvements are available. Two immediate simple solutions-using the correct type and concentration of lubricant and carrying out regular maintenance-would significantly reduce emissions from two-stroke engines while saving drivers money and ultimately improving air quality. Promoting these "win-win" measures requires building public awareness by disseminating information on the health impact of emissions; the types of engines, fuel, and lubricant that reduce emissions; the importance of regular maintenance; and the advantages and disadvantages of various measures for mitigating air pollution. Partnerships among government, industry, and the public will continue to be crucial to bring about the changes required to achieve air quality goals.