Language proficiency is a key driver of immigrant integration. It increases job opportunities and facilitates social and political participation. However, despite its vital importance, many immigrants never reach adequate proficiency in the host country language. Therefore, insights into the underlying processes and associated factors are crucial for designing measures to improve language acquisition. Empirical evidence shows that immigrants differ in their ability to learn languages, in their experience of everyday language usage, and their incentives to learn host country languages. This offers a range of opportunities for public policy intervention.
We study the impact of short-term exposure to ambient air pollution on the spread and severity of COVID-19 in Germany. We combine data at the county-by-day level on confirmed cases and deaths with information on local air quality and weather conditions. Following Deryugina et al. (2019), we instrument short-term variation in local concentrations of particulate matter (PM10) by region-specific daily variation in wind directions. We find significant positive effects of PM10 concentration on death numbers from four days before to ten days after the onset of symptoms. Specifically, for elderly patients (80+ years) an increase in ambient PM10 concentration by one standard deviation between two and four days after developing symptoms increases the number of deaths by 19 percent of a standard deviation. In addition, higher levels air pollution raise the number of confirmed cases of COVID-19 for all age groups. The timing of effects surrounding the onset of illness suggests that air pollution affects the severity of already-realized infections. We discuss the implications of our results for immediate policy levers to reduce the exposure and level of ambient air pollution, as well as for cost-benefit considerations of policies aiming at sustainable longer-term reductions of pollution levels.
