Apples and oranges. The EPA primary standard (which is they propose to change) is based only on health and not economics.

From the Regulatory Impact Analysis[1]:

(yes it's long, but the quote preempts a lot of the predictable replies here)

>The Clean Air Act (CAA) requires the EPA, for each criteria pollutant, to set standards that protect public health with “an adequate margin of safety” and public welfare from “any known or anticipated adverse effects.” As interpreted by the Agency and the courts, the CAA requires the EPA to base the decisions for primary standards on health considerations only; economic factors cannot be considered. The prohibition against considering cost in the setting of the primary air quality standards does not mean that costs, benefits, or other economic consequences are unimportant. The Agency believes that consideration of costs and benefits is an essential decision-making tool for the efficient implementation of these standards. The impacts of costs, benefits, and efficiency are considered by the States when they make decisions regarding what timelines, strategies, and policies are appropriate for their circumstances.

TL;DR: Primary standards are meant to determine healthy levels, including for vulnerable people like children and the elderly. They are not intended to determine what levels are economically efficient. That's handled during implementation, not when setting the primary standards.

[1] https://www.epa.gov/system/files/documents/2023-01/naaqs-pm_...