Smog Levels "Technically" Low, but Remain Unhealthy

Many probably noticed the hazy and smoggy conditions today in the Denver metro area, especially in the morning. The picture below, from 9 in the morning, shows the dirty sky. Smog levels have technically been low so far in August, although new recommendations from scientists suggests that smog levels have remained unhealthy. In fact, scientists have recommended the U.S. Environmental Protection Agency set a smog, or ozone, standard as low as 55 parts per billion, over 30% stronger than the current standard of 80 parts per billion. Ozone levels at several monitors in the Denver area exceeded 60 parts per billion today.

Although smog levels were technically low, levels of nitrogen oxides appear to have approached dangerous concentrations today. Not only are nitrogen oxides dangerous on their own, they also contribute to smog pollution and acid rain.


Under the Clean Air Act, annual concentrations of nitrogen oxides cannot exceed 0.053 parts per million anywhere. Nitrogen oxide levels at the air monitor at 2105 Broadway reached 0.061 parts per million today. Although this may not indicate a violation of the yearly standard, it does show that nitrogen oxide levels today contributed to unhealthy air in Denver. But again, this was likely obvious to any of us that ventured outside.