The U.S. Environmental Protection Agency (EPA) last week finalized new regulations for sulfur dioxide (SO2) emissions.
A new one-hour standard is expected to protect millions of Americans from short-term exposure to SO2, which is primarily emitted from power plants and other industrial facilities. Exposure to SO2 can aggravate asthma and cause other respiratory difficulties.
This is the first new standard for SO2 in nearly 40 years.
EPA is setting the one-hour SO2 health standard at 75 parts per billion
(ppb), a level designed to protect against short-term exposures ranging
from five minutes to 24 hours. EPA is revoking the current 24-hour and
annual SO2 health standards because the science indicates that
short-term exposures are of greatest concern and the existing standards
would not provide additional health benefits.
EPA scientists recommended cutting the short-term standard in a range of 50 to 150 ppb.
EPA is also changing the monitoring requirements for SO2. The new
requirements assure that monitors will be placed where SO2 emissions
impact populated areas. Any new monitors required by this rule must
begin operating no later than Jan. 1, 2013. EPA is expecting to use
modeling as well as monitoring to determine compliance with the new
standard.
The final rule also changes the Air Quality Index to reflect the revised
SO2 standard. This change will improve states’ ability to alert the
public when short-term SO2 levels may affect their health.
"Moving to a one-hour standard and monitoring in the areas with the highest SO2 levels is the most efficient and effective way to protect against sulfur dioxide pollution in the air we breathe," EPA Administrator Lisa Jackson said in a release.
EPA estimates the health benefits associated with this rule range between $13 billion and $33 billion annually. These benefits include preventing 2,300 to 5,900 premature deaths and 54,000 asthma attacks a year. The estimated cost in 2020 to fully implement this standard is approximately $1.5 billion.
The first National Ambient Air Quality Standards for SO2 were set in 1971, establishing both a primary standard to protect health and a secondary standard to protect the public welfare. Annual average SO2 concentrations have decreased by 71% since 1980.
The final rule addresses only the SO2 primary standards, which are designed to protect public health. EPA will address the secondary standard–designed to protect the public welfare, including the environment–as part of a separate review to be completed in 2012.
EPA expects to identify or designate areas not meeting the new standard by June 2012.
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