Revealing the Link Between Air Pollution and Internal Migration: Evidence from Italy

People move for various reasons, including economic, social, political, demographic, and environmental factors. Environmental quality, in particular, plays a crucial role in migration decisions. This study examines the relationship between air pollution (measured as the maximum number of days in which at least one monitoring station detects an excess of 50 µg/m3 of PM10 above the established limit) and internal migration in Italy. Employing a difference-in-differences (diff-in-diff) strategy, our analysis reveals a negative relationship between air pollution and internal migration. We exploit two major legislative interventions in environmental regulation — LD 152/2006 and LD 155/2010 — as exogenous shocks affecting air pollution. We find that these environmental regulations significantly reduced the number of pollution exceeding days in municipal areas, thereby enhancing the attractiveness of those areas more committed to reducing urban emissions. Specifically, the combined effect of the two decrees led to an increase of approximately three new citizens per 1,000 inhabitants in the more committed areas, highlighting the importance of proactive environmental policies in influencing migration patterns and improving urban livability.