Our View: Smoke is ugly; invisible ozone is a greater danger

When you see something that looks like a bruise in the sky, it’s not a good sign.

But that’s how it looked Wednesday – yellowish, brown and thick – as smoke from the Tesla fire gathered in a huge cloud hanging low in the sky from Manteca to north Modesto. You could see it from Livingston and Oakdale.

What gives such a cloud its color is particulate matter, which, in high concentrations, makes it dangerous to breathe for many groups; the San Joaquin Valley Air Pollution Control District issued warnings to that effect for parts of San Joaquin County.

Thursday was different. The air above Modesto and Manteca had cleared a great deal by the afternoon (thank you, Delta breezes), but the fire that created the original cloud it isn’t out yet.

The Tesla fire had burned 2,500 acres of grassland on a ranch east of Livermore. It was only 25 percent contained as of Thursday. If the wind dies down, or shifts dramatically, that smoke could gather over us again.

“If you smell smoke,” said air board spokesperson Heather Heinks, “it’s having an impact and you’re breathing in particulate matter, in which case you should probably go indoors.”

It’s easy to heed such common-sense advice.

It’s harder, perhaps, when you can’t see or smell the danger. But it’s also more important to heed the warnings.

One of the nastiest components of our air is ozone, formed when organic compounds, including exhaust emissions from vehicles, begin to bake in the afternoon heat. It’s nastier than the smoke and more dangerous to children when it enters their lungs – especially now, as school resumes.

“Our plea is ‘Turn the key; be idle-free,’” said Heinks. “When all those cars that were turned off for the summer are back and waiting in front of schools to pick up children, we see direct spikes” in ozone levels.

When the ozone levels go above 60, they are becoming dangerous. When they approach 100, the district issues warnings. No one should let children play outside when ozone levels are in that range. Generally, it occurs from 2 to 5 p.m. – just as many children are leaving school and eager to get outside.

For healthy kids, exposure to that level of ozone can lead to sore throats and wheezing. For kids with asthma, it can create difficulty breathing, make them dizzy and, in the worst cases, send them to the emergency room unable to draw breath. When ozone levels are that high, it’s simply not safe to play outdoors.

That ugly smoke that bruised our sky this week is nasty, but the invisible stuff that we contribute to by running our motors to keep the inside of our cars cool is much, much worse. Like many bad things, you never see the dangerous stuff coming. Help your kids; turn off your car when waiting to pick them up from school.

This story was originally published August 20, 2015 at 4:23 PM with the headline "Our View: Smoke is ugly; invisible ozone is a greater danger."