A decent proposal? EPA's new clean air standards.
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D000393:Air Pollutants / Q000009:adverse effects / Q000032:analysis; D000397:Air Pollution / Q000331:legislation & jurisprudence* / Q000517:prevention & control*; D004784:Environmental Monitoring / Q000592:standards*; D006801:Humans; D010083:Oxidants, Photochemical / Q000009:adverse effects / Q000032:analysis; D010126:Ozone / Q000009:adverse effects / Q000032:analysis; D014481:United States; D014484:United States Environmental Protection Agency
D000393:Air Pollutants; D010083:Oxidants, Photochemical; D010126:Ozone