要旨：I develop a monopolistic competition model with pollution to analyze the effects of environmental policy on the average productivity of a country. In the model, firms are heterogeneous in their productivity. Given a particular distribution function of technology, I show that a stricter environmental policy will increase average productivity, and will have positive effects on the marginal decrease of profits and environmental damage. In addition, I show the optimal tax rate in a closed economy. In an open economy model, the environmental policy of a country will affect the average productivity of a trading partner. In other words, a stricter environmental policy in a home country leads a decrease in the productivity of a foreign country.

要旨：Investigations of the effect of quality differences on heterogeneous performance in exporting have been limited by lack of direct measures of quality. We examine exports of French wine, matching the exporting firms to producer ratings from two wine guides. We show that high quality producers export to more markets, charge higher prices, and sell more in each market. Exports of champagne exhibit a pattern of quality sorting predicted in our model. More attractive markets are served by exporters that, on average, make lower rated champagne. Market attractiveness has a weakly negative effect on prices and a strongly positive effect on quantities, confirming the sign predictions of a simple quality sorting model.