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Wednesday, June 21, 2023

Air Pollution Has Plummeted in the U.S. Over the Last Half Century

NYC went from 300 days of unhealthy air per year to less than 50. Economics explains how it happened.

Image Credit: Created by author

Earlier this month, as wildfires ravaged Canada, the Northeastern United States experienced heavy air pollution problems from the smoke.

The out of control fires and subsequent pollution is a tragedy, certainly. But the fact that a low-visibility New York City was national news highlights how much things have changed.

Pollution has dramatically declined over the past few decades. To get a clear picture of how much, look at this graph.

Source: US Department of Transportation

This shows the number of days air quality is considered to be at “unhealthy levels” by the US government in seven major metros in the U.S.

All seven metros have improved their air quality since 1980. This is good news!

In the NYC metro, nearly 300 days in 1980 had unhealthy air quality. Today it’s less than 50.

So what’s going on here? Well, some might argue regulation is the primary source. It’s certainly possible that environmental regulations in the end of the 20th century resulted in less pollution. As our technology has improved, we’ve gained the ability to police people polluting the air of their neighbors. But this isn’t the full story.

Wealth Makes Health

To understand the fundamental reason why the environment has improved, we should consider the work of Nobel Prize-winning economist Simon Kuznets.

Kuznets examined the relationship between income inequality and development. What he found was, as a country becomes wealthier, inequality begins to increase—at first. But as countries continue to become wealthier, this inequality falls over time. Economists call this relationship, the Kuznets curve.

In other words, as countries get wealthier the wealth begins to concentrate, but it spreads out over time.

A similar pattern has revealed itself over time in environmental economics. The “environmental Kuznets curve” describes how, as poor countries start to get richer, their environments get worse, but then it improves!

Getting rich requires using natural resources. Countries begin extracting minerals, chopping down trees, and burning fuel to lift themselves out of poverty.

However, when these countries get rich, people demand a better environment. This demand drives innovation which leaves the environment improved.

To slightly modify a quote by economist Julian Simon, “more people, and increased income, cause [environmental degradation] in the short run. The [demand for a cleaner environment] present[s] opportunity and prompt[s] investors and entrepreneurs to search for solutions. Many fail in the search, at cost to themselves. But in a free society, solutions are eventually found. And in the long run the new developments leave us better off than if the problems had not arisen.”

So while bad environmental events, like forest fires, still occur, the overall trend is that humans can increasingly adapt to environmental challenges. So take a deep breath and enjoy the cleaner air.


  • Peter Jacobsen is a Writing Fellow at the Foundation for Economic Education.