Demand for air quality depends on health impacts and defensive investments that improve health, but little research assesses the empirical importance of defenses. We study an important cap-and-trade market, which dramatically reduced NOx emissions, a key ingredient in ozone formation. A rich...

The demand for air quality depends on health impacts and defensive investments, but little research assesses the empirical importance of defenses. A rich quasi-experiment suggests that the Nitrogen Oxides (NO_x) Budget Program (NBP), a cap-and-trade market, decreased NO_x emissions, ambient ozone...