The ATS submitted comments to the EPA Clean Air Scientific Advisory Committee or CASAC - an EPA-convened panel of experts to advise the agency on clean air standards - regarding CASAC’s review of the current ozone and particulate matter pollution standard. The ATS noted that the EPA and CASAC appear to be rushing the review process, reducing opportunities for public input and not seeking expert input from the scientific community. The ATS further opposed the EPA’s proposal to weaken its statement on causality between exposure to ozone pollution and mortality. In its prior O3 ISA, the EPA concluded that there was a likely causal relationship between ambient O3 exposure and all-cause mortality. However, the Agency is now proposing to downgrade this determination to “suggestive of, but not sufficient to infer, a causal relationship.” In comments to CASAC, the EPA opposed the change in causality determination and noted several US and international studies that continue to demonstration a causal link between ozone exposure and premature mortality.