Earth Log

June 17, 2014

Ozone's June swoon — enjoy it while you can

Earth Log

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

OK, you can exhale. Now breathe a little. Not great, but not bad, right? It's time for ozone's June swoon.

That's right, air pollution takes a dive for about half of this month -- in most years. That's been true in the San Joaquin Valley for the last five years. Let's hope it happens again this year.

Instead of leading the nation in ozone exceedances at this time of year, the Valley is usually in a pack of other air basins.

The dirty-air pack looks like this: Eastern Kern County, Coachella Valley, Antelope Valley/West Mojave Desert and South Coast. California is the biggest smog trap in the country, and this group is the worst of the worst.

Right now, the air is mixing with breezes. The temperature has dropped from those scorching 100-degree days of last week. Traffic seems lighter in the morning with school out. These conditions are not friendly for ozone formation.

The story was different in 2008 when thousands of wildfires dumped ozone-making gases into California's air. Everyone had a problem. The Valley got only nine days without an exceedance that year.

In this drought year, wildfires could get crazy again. Keep your eye on the real-time monitors of the San Joaquin Valley Air Pollution Control District.

And enjoy this while it lasts. Valley summers give you three good reasons to be cautious about ozone -- July, August and September.

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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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