Tweet Over the US Thanksgiving holiday, well, actually in the news hole right before it, on Wednesday afternoon, US EPA announced new rules for ambient ozone, dropping the current limits from 75 ppb to 65-70 ppm with fairly long timelines to meet those limits. What the EPA means by such a standard is that the an area would meet the primary standard if the fourth highest maximum daily 8-hour ozone concentration per year averaged over three years is equal to or less than the standard  Neela Banerjee and Tony Barboza in the LA Times describe the new rules and the reaction to it, principally from the usual suspects who have never been right when they declared the end of the world as we know it due to some environmental improvement. They have a pretty good Mom Rabett level explanation of how the ozone is formed Ozone is created when unstable gases are released during combustion, whether at power plants, factories or in vehicle engines. The pollutants react with sunlight to create ozone, which can trigger asthma attacks, worsen heart and lung disease and lead to premature deaths.