Business groups say a Biden administration proposal to toughen standards for a deadly air pollutant would create a "regulatory burden" and could "stifle manufacturing." The Environmental Protection Agency says tougher standards for soot from tailpipes, smokestacks and wildfires could prevent thousands of premature deaths a year. A proposal released Friday by the EPA would set maximum levels of 9 to 10 micrograms of fine particle pollution per cubic meter of air, down from 12 micrograms. The American Lung Association wants the EPA to lower the standard to 8 micrograms. The association reports Fresno, California, is the metropolitan area with the worst short-term particle pollution.