Thesis: The three chapters of this thesis are independent and contribute to environmental economics through different approaches. The first chapter, Inter-Firm and Intra-Firm Spillover Effects of Industrial Regulation, co-authored with Geoffrey Barrows, Raphael Calel, and Hélène Ollivier, presents a new method for estimating the impact of a regulation in the presence of inter- and intrafirm spillover effects. In particular, when competition is imperfect, a regulation targeting some firms is also likely to affect unregulated firms. Thus, the traditional difference-indifferences approach will not evaluate the full impact of the regulation. To overcome this limitation, we develop a structural model and an empirical strategy to estimate the effects of a regulation affecting a sub-population of industrial facilities. We apply our method to the European Emission Trading System and show that it reduced carbon emissions from regulated facilities as well as from the French manufacturing sector as a whole, butincreased revenues of regulated French firms. While pollution should be reduced in more densely populated locations, stringent regulations may also harm local industries and reduce workers’ incomes. In the second chapter, entitled An Optimal Distribution of Polluting Activities Across Space, I analyze these conflicting forces using a spatial economics model to identify which cities should be targeted by air quality policies. When the effects of pollution are not internalized by firms and workers respond to poor air quality by migrating away, then the largest cities may be too small compared to the optimum. Imposing a higher pollution price in these locations relative to the rest of the country would lead to higher welfare. The empirical application on French cities shows that current policies impose higher emission prices in large cities, but welfare gains are still possible. There is a lot of evidence that air pollution has negative effects on the productivity of industrial workers. However, little is known about its consequences on the economic performance of firms that employ these workers. In the third chapter, The Effects of Air Pollution on Exports: Evidence from PM2.5 & French Firms, co-authored with Geoffrey Barrows and Hélène Ollivier, we examine the effects of temporary and local increases in PM2.5 air concentration on the exports of French firms. Our approach relies on highly disaggregated data, both in space and in time. To estimate the causal impact of pollution on exports, we instrument local pollution concentrations using exogenous variations in wind direction over time. We find that higher pollution levels lead to lower export values and quantities.