The world's urban population is expected to more than double between 2000 and 2050, yet emissions of health- and climate-relevant pollutants associated with the operation of urban infrastructure systems must be dramatically reduced. Given limited resources, it is essential to implement technologies and policies that simultaneously provide high climate and health benefits per unit effort. This seminar will introduce a mechanistic, source-oriented approach to studying human exposure to urban air pollution and its application to the design of high-impact control strategies. The results of two recent studies will be presented to illustrate this approach: a field investigation of in-vehicle exposures to particulate matter (PM) in New Delhi, India; and a mathematical model of intraurban exposure to air contaminants emitted by vehicles and other ground-level sources in ~3600 major worldwide urban areas. The seminar will then introduce proposed research on the climate, health and energy impacts of the ubiquitous diesel electricity generators ("gensets") that operate in Indian cities. Indian gensets have escaped rigorous academic attention, yet may have surprisingly large environmental impacts. The proposed work seeks to quantify the environmental and health benefits of policies and technologies aimed at reducing the need for diesel-powered electricity in India.