IN THE debate over climate change, policies to reduce pollution are often seen as detrimental to economic growth. But this need not always be the case. As we pointed out last month, policies such as cutting fossil-fuel subsidies can both cut carbon emissions and boost growth. A new paper* suggests another measure to curb pollution that may have had beneficial long-term economic impacts for individuals. The paper’s authors, Adam Isen, Maya Rossin-Slater and Reed Walker, compared the adult labour-market outcomes of those born in counties in America where air pollution decreased as the result of the 1970 Clean Air Act to those born in areas where pollution did not fall in this period. They found that those who were born in counties that were forced to cut air pollution as a result of the legislation earned more by their thirties than they would have otherwise: gaining approximately $4,300 each in extra income over their lives.

At first, this result may seem a little strange. As dirty industries closed in many affected areas as a result of the Clean Air Act, one would expect incomes to fall as the result of increased unemployment. Yet the authors of the paper found the opposite: the long-term benefits of better childhood health on adult incomes outweighed the other negative immediate economic effects that may have resulted from the legislation.

The impact of air pollution while growing up is not the only factor that affects adult outcomes, economists reckon. Supporters of the so-called “fetal origins hypothesis” have long been convinced that being conceived or born during a famine or an economic depression can reduce your adult life expectancy, and increase the chance of having conditions such as heart disease and diabetes in old age. And, according to this paper, exposure to pollution when young may affect you for the rest of your life. More evidence, it seems, that the long term benefits of environmental proposals—and not just those that materialise in the immediate future—need to be considered with more care by politicians.

* "A. Isen, M. Rossin-Slater and R. Walker, "Every breath you take—every dollar you'll make: the long-term consequences of the Clean Air Act of 1970", NBER working paper 19858, January 2014.