The Most Polluted Cities On All Seven Continents [CHART]

Via Jefferies, the global investment banking firm, here are the most polluted cities in the world, by continent. They are ranked according to their annual average levels of airborne particles with a diameter of 10 micrometers or less (PM-10).

These tiny particles are the most likely to cause adverse health effects on the respiratory system, including asthma and trouble breathing. The U.S. Environmental Protection Agency recommends that yearly averages not exceed 50 micrograms per square meter (ug/m³).

The EPA says:

Major concerns for human health from exposure to PM-10 include: effects on breathing and respiratory systems, damage to lung tissue, cancer, and premature death. The elderly, children, and people with chronic lung disease, influenza, or asthma, are especially sensitive to the effects of particulate matter. Acidic PM-10 can also damage human-made materials and is a major cause of reduced visibility in many parts of the U.S.

Here's the chart:

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