A substantial reduction in air pollution in a part of the Czech Republic that had suffered from high concentrations of sulphur dioxide in communist times started repopulation of the region, which was primarily driven by a substantial decline in emigration. That is one of the findings of new research by Štěpán Mikula and Mariola Pytliková.
The study also finds that the effect of air pollution on emigration was far stronger in municipalities with weaker local social capital and in municipalities with poorer facilities in terms of education, health, social care, culture and sport. The results thus imply that the burden of air pollution may be partly compensated by local social capital and man-made amenities.
Air pollution is harmful to human health and has detrimental impacts in the range of socio-economic outcomes. Given those serious adverse effects of exposure to air pollution, one would expect that people prefer to live and raise their children in environmentally clean areas, and thus move out from polluted areas.
This study identifies causal impacts of extreme air pollution levels on residential migration by using a natural experiment, which took place in the region of North Bohemia, Czech Republic, in 1990s.
The North Bohemian region is rich in lignite, which encouraged the communist government of former Czechoslovakia to build a dense cluster of large lignite-burning power plants within the area. Concentration of power plants, specific topology of the region and lack of desulfurization technologies led to extreme air pollution of the region. In the 1980s, the annual mean sulphur dioxide (SO2) concentrations exceeded 80 μg/m3 in 1980s surpassing even Beijing’s average level of 71 μg/m3 in 2000 (UNEP 2007) and 20 μg/m3 EU/WHO annual limits.
Despite knowing the adverse effects of the air pollution, the communist government did not invest in any measures that would decrease the pollution concentrations nor informed the general public on related health risks.
Soon after the fall of the communist regime in 1989, the new democratic government started programmes aimed at improving the environment. In 1991 they set on obligation to power plant to adopt modern desulphurisation technologies within seven years, which consequently led to a substantial drop in the emitted pollution, but per se did not affect economic activity in the region.
The technology adoption led to a rapid decrease in levels of SO2 concentrations in the affected areas. In fact, the reduction in SO2 emissions in the Czech Republic was one of the most dramatic historical examples of pollution reduction in Europe ever (Vestreng et al, 2007).
The results based on a difference-in-difference estimator show that the reduction in air pollution started repopulation of the region primarily driven by a substantial decline in emigration. The effect is large, causing on average 24% decrease in emigration rates from polluted municipalities after the desulfurization technologies were adopted.
Further, the study finds the effects on emigration to be non-linear in the sense that the effect is much larger for municipalities that initially suffered heavy SO2 levels (annual mean concentration 50 and 60 μg/m3) with a size of almost twice as large compared to municipalities that suffered lower pollution (40 μg/m3).
The researchers dig deeper into factors that shape the migratory responses to air pollution. Specifically, they investigate the role of economic benefits acting as anti-emigration policy and the role of social capital and man-made amenities in counteracting the effect of environmental pollution on migration. For that, they exploit additional natural experiment and other historical set-ups to study channels that are otherwise hard to disentangle.
The results based on a triple difference estimator show that that anti-emigration policies had no impact on emigration decisions. Further, the effect of air pollution on emigration was far stronger in municipalities with weaker local social capital and in municipalities with poorer facilities in terms of education, health, social care, culture and sport. The results thus imply that the burden of air pollution may be partly compensated by local social capital and man-made amenities.
Štěpán Mikula,
Masaryk University, Lipová 507/41a 602 00 Brno, Czech Republic
Stepan.Mikula@econ.muni.cz, +420724512946.
Mariola Pytliková:
CERGE-EI Charles University Prague, VŠBTUO, IZA, CReAM and CELSI;
CERGE-EI, Politických vězňů 7, 11000 Prague 1,