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...

The U.S. Environmental Protection Agency (USEPA) maintains networks of pollution monitors for two basic purposes: to check and enforce the attainment of national ambient air quality standards (NAAQS) and to provide useful data for studying pollution and its effects. These purposes imply...