A long, hard slog on ozone limit

The federal announcement last week of plans to tighten rules on ozone don’t quite end the suspense for Colorado’s Front Range. We already knew the Environmental Protection Agency intended to lower the ozone limit; the question was by how much.

As it happens, the EPAdidn’t precisely answer that critical question. Instead, EPAAdministrator GinaMcCarthy said the final standard, which could be announced next fall, will be “in the range of 65-70 parts per billion.”

That compares with 75 ppb today.

For Colorado, the difference between 65 and 70 ppb is quite significant, as the state hasn’t been able to comply even with the current limit— although it is making progress.

It would likely take many years and some fairly difficult decisions by the state in order to comply with any standard in the lower part of that range.

This is not an argument against a new limit, by the way, but a call for maintaining a long-term per- spective. The important thing is for the state to make progress whatever the next ozone standard might be.

Ozone is a secondary pollutant, the result of photochemical reactions involving nitrogen oxides (NOx) and volatile organic comopounds (VOCs). Vehicles and power plants are big sources of NOx. Oil and gas operations are a major source of VOCs. But how these emissions all interact is extremely complex.

For example, scientists are still trying to get a handle on the extent to which energy development may contribute to ozone, although a study underway by Boulder’s National Center for Atmospheric Research should help clarify the matter.

Cleaner cars and power plants will help, as will regulations on emissions from oil and gas sites. But there’s no silver bullet for meeting the next ozone standard, and officials should avoid proposals whose intrusive nature could fuel public resentment.

It’s going to be long, hard slog.