Before and After: Cleaning up Our Cities
Around the world, cities plagued by smog have tried to clear up the skies among the skyscrapers. Discover their successes by comparing photos from before and after changes were made by local governments
- By Erica R. Hendry
- Smithsonian.com, March 21, 2011
(left: ImageState / Alamy; right: Cameron Davidson / Alamy)
Almost every year during the 1980s, Baltimore and other areas of Maryland spent 20 or more days each summer under Code Red Conditions, a measure of air quality issued when pollutants like volatile organic compounds and nitrogen oxides in the ground-level ozone are higher than the federal health standard. The pollutants left a gray blanket hanging above the city, prompting health agencies to urge children, the elderly and those with respiratory problems to stay inside. But since then, most of the industry (including one of the largest steel mills in the country) that once marked the blue-collar city is gone, says Jonathan Samet, the director of the University of Southern California's Institute for Global health. The power plants around the inner harbor are mostly empty, which means fewer high-emissions trucks and other vehicles pass through the city. The factories that still exist are now powered with natural gas, making the air much easier to breathe.