On June 3, the Environmental Protection Agency (EPA) announced a new health standard for sulfur dioxide (SO2) that will protect against short-term exposure to the compound and result in estimated annual health benefits of $13 billion to $33 billion.

The new one-hour limit replaces 24-hour and annual exposure guidelines that were created almost 40 years ago. Studies have shown that short-term exposure is responsible for the majority of SO2-related health problems. SO2, which is emitted from coal-fired power plants and industrial facilities, can lead to and exacerbate lung problems and cause acid rain. It is particularly harmful to people with respiratory conditions, children and the elderly.

A recent National Research Council study estimated that 49,000 deaths and 450,000 serious illnesses resulted from SO2, nitrous oxides, and other pollutants emitted by coal-fired power plants. (For more information on the health costs of various energy sources, please click here .)

In accordance with the new standard, revamped SO2 monitoring requirements will ensure that monitors are placed in populated areas and the Air Quality Index will be adjusted to allow states to issue public alerts when short-term SO2 levels are elevated. The EPA estimates that it will cost impacted plants and factories $1.5 billion to fully implement the standard over the next 10 years.