WASHINGTON (AP) — The Environmental Protection Agency's staff concludes that the government needs to tighten smog rules by somewhere between 7 and 20 percent. In its final recommendation in a 597-page report, the agency staff agrees with EPA's outside scientific advisers that the 6-year-old standard for how much smog is allowed needs to be stricter. Since 2008 the standard allows up to 75 parts of ozone per billion parts of air.Read more on NewsOK.com