Medical research has long supported the fact that exposure to fine particulate matter increases the risk of various respiratory, cardiovascular, and pulmonary illnesses.

FORBES: Two New Reasons to Worry about Air Pollution: Obesity and Diabetes

Incidences of asthma, heart attacks, and chronic bronchitis are all higher in areas where the concentration of fine particulate matter is higher.

FORBES: Two New Reasons to Worry about Air Pollution: Obesity and Diabetes

In January, levels of fine particulate matter measured by the U.S. Embassy in Beijing reached a level 35 times the World Health Organization's recommended standard.

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Sulfur dioxide produces fine particulate matter and acid rain.

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The study compared mice fed a high-fat diet with those fed a normal, healthy diet, and exposed some members of both groups daily to fine particulate matter, controlling for all other factors.

FORBES: Two New Reasons to Worry about Air Pollution: Obesity and Diabetes

The report also says that the congestion charge has caused reductions in the two most concerning pollutants to London, by 8% for nitrogen oxides and 7% for particulate matter that is fine enough to penetrate the lungs and cause health problems (referred to as PM10).

FORBES: Paul Maidment

Consider, for example, a spate of new studies that have found a rather convincing correlation between the presence of small particulate matter (PM2.5, the fine particles blown into the air by road traffic, coal-fired power plants, industrial manufacturing, and residential wood fuel combustion) and both obesity and diabetes.

FORBES: Two New Reasons to Worry about Air Pollution: Obesity and Diabetes