The demand for air quality depends on health impacts and defensive investments that improvehealth, but little research assesses the empirical importance of defenses. We study the NOxBudget Program (NBP), an important cap-and-trade market for nitrogen oxides (NOx) emissions,a key ingredient in...

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...