Tracey Holloway
University of Wisconsin, USA

Whether you remember the 1970s, or – like me – have seen hazy skylines in movies like Rocky, you may notice something has changed. The U.S., like many other industrialized countries, has drastically cleaner air today than in decades past.

A layer of haze used to be a common part of city life. While occasional bad air days still occur throughout the U.S., on most days, in most cities, the air is clear and and for the most part healthy. If you could breathe that ‘70s air, you would feel the difference in your lungs, your eyes, and your life expectancy

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