Today's cleaner air is mostly thanks to science-based air pollution standards. Last week, science advisors to the US Environmental Protection Agency or EPA, drafted a letter criticizing the agency's use of science to set ambient air pollutant standards. This is the latest development in the EPA's process to update the health protective standards for particulate matter and ozone, the two air pollutants most responsible for early death and sickness in the US. These developments risk unraveling the methodical process that, for decades, has effectively ensured we have science-based air pollution standards and steady reductions in air pollution.
The EPA must only consider the science that answers the question of what protects all people, including sensitive populations, such as the elderly, children, and those with lung and heart diseases. In assessing the science and the standards, the EPA relies on expert advice from the seven-member Clean Air Scientific Advisory Committee or CASAC, which has always been supplemented by a panel of additional experts on particular pollutants under review.
CASAC, with help of the review panel, will then make an official recommendation for what level of air pollution will protect public health with an adequate margin of safety. Together these three documents, and CASAC's recommendation, go to the EPA administrator who will ultimately set the standard. Thus, CASAC and the scientific assessment are essential because they inform this entire process and ensure that the EPA is basing policies on the best available science.
However, a letter from CASAC chair Louis Anthony Cox Jr released this month essentially trashes the EPA science assessment, inexplicably calling the lengthy, exhaustingly referenced document "unverifiable opinion" and claiming that it fails to follow the scientific method. Dr. Cox calls for a brand new approach, asking the agency to throw away the long used and scientifically backed weight-of-the-evidence framework in order to determine the health effects of air pollution.
On March 28, CASAC will hold its next meeting to discuss the draft letter and the committee's final recommendations on how EPA should finalize its science assessment. At this point, it is unclear what the committee will collectively decide, and whether they will have any consensus comments for the EPA. What is clear is that the EPA's process for updating air pollution standards is changing in ways that threaten the agency's very use of science to protect the public from air pollution.
