Earth Log

June 10, 2014

Clovis, you're having an air problem

Earth Log

Mark Grossi's dispatches from the Valley battle with air quality and water use

It's Tuesday. We've gone nine straight days exceeding the federal eight-hour ozone standard. Let's keep talking about air. 

Clovis, you're having an air problem.

Aside from the 13 bad days so far for Clovis, the ozone peak came your way on Monday in this heat wave.

Between 1 p.m. and 2 p.m., your monitor showed 112 parts per billion -- just 13 away from the one-hour or peak ozone threshold. 

You may recall the peak threshold is the one that the San Joaquin Valley appears to have achieved. I checked with the U.S. Environmental Protection Agency, which told me its analysts are still studying the issue.

Back to Clovis, it's important for parents to keep an eye on the real-time monitoring online from the San Joaquin Valley Air Pollution Control District. Keep your kids inside when the ozone spikes.

For years, I've been writing about the light breezes that tend to guide the exhaust and emissions from Fresno's morning commute to places like Clovis and Parlier. It takes a few hours, but these gases cook in the sun to become ozone.

Besides traffic, what creates the gases? Gasoline-powered yard equipment is among the sources -- lawn mowers, hedge-trimmers and leaf-blowers. But the biggest source is diesel trucks.

The state offers a long list of these sources, including farm equipment, construction bulldozers, trains, aircraft, boats and motor homes. You can see the list and the size of the contribution each source makes.

There's much more to the story. But for this week, it's important to know now is the time to curb activities that make these gases. 

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About Mark Grossi


Mark Grossi has the pulse of the San Joaquin Valley ecosystem, writing since 1993 about subjects such as the region's notorious air quality, the restoration of the San Joaquin River and unhealthy drinking water in rural towns. Twitter: @markgrossi Email Mark at or call him at 559-441-6316.

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