Soundings: Ozone: What now? |

Soundings: Ozone: What now?

This is the third in a series of columns on our county’s air quality problem (previous columns can be found in The Union’s on-line archives at, or on the Web site of Save The Air in Nevada County;

To summarize: Chemicals pumped into the air in the Bay Area, in Sacramento, and in the agricultural fields of the central valley are “ozone precursors.” Cooked by the sun, they react to form highly toxic ozone.

Ironically, some ozone precursors become ozone scavengers at night. Ozone levels of the urban source regions drop after sunset … but levels in the foothills stay high.

Evidence suggests that some of the effects of ozone can be ameliorated by antioxidants such as vitamins C and E (though, as with any physiologically active substances, beware of excess).

Oxygen atoms are greedy for electrons, the particles that glue atoms together to make molecules, molecules together to make the world around us … and us.

Snatching up these electrons, oxygen destroys bonds: Molecules and tissues fall apart.

While the ordinary, garden-variety oxygen we breathe is very effective at electron thievery – “oxidation” – ozone is much more effective: It cracks rubber, scars lungs.

Alveoli are tiny “sacks” that grow in the deepest parts of the lung, to transfer oxygen from the air to the blood. They continue to develop after a child is born. But when Michelle Fanucchi (UC Davis) raised young monkeys in ozone-polluted air, their alveoli developed oddly: In the tubes leading into the lungs – perhaps, Fanucchi says, because the animals were taking shallow breaths, rather than pulling air deep into their lungs.

Even after new carpet smell becomes unnoticeable, carpets (and other indoor accouterments) continue to outgas. Some of these molecules are innocuous; some are toxic.

Many of these outgassed molecules are attractive targets for ozone. Stealing their electrons, the ozone may also donate an oxygen atom to the molecule, turning it into something else (the principle behind ozonating “air purifiers”).

In the process, the ozone itself is destroyed.

When a catastrophe occurs that would call for evacuation, but evacuation isn’t feasible, local residents are advised to “shelter in place” (SIP) – to remain indoors. Because indoor air usually contains less ozone than that outdoors, SIP is the preferred strategy during high-ozone events: Avoid outdoor exertion – stay indoors.

Unfortunately, studies by Charles Weschler (Rutgers) and colleagues indicate that some of the products of ozone reactions are more toxic than the original, outgassed molecules … and some are even more toxic than ozone.

Environmental agencies presume that so-called “background” levels of ozone are safe to breathe … but new research suggests there’s no threshold – that any amount of ozone can damage the lungs of those who are susceptible.

Ozone precursors are not the only gases that make air dangerous … many other toxins are emitted from the tailpipes and smokestacks … and yet, we see drivers idling their engines as they await their kids’ emergence from school (wouldn’t parking a block or two away, and walking, almost certainly be faster?) … drivers idling their cars while parked, so as to enjoy the air conditioning.

Of course, the bulk of our air pollution is transported into the foothills from communities upwind. How can we convince these communities to burn less fuel … especially when their future plans call for more roads, more cars, more burned fuel?

Current air quality plans call for our air to meet (weak) regulatory requirements by 2014. But new plans, under review, would extend that deadline to 2024.

We can’t wait that long.


Alan Stahler trained as a biologist and is an amateur astronomer. He teaches private enrichment classes for students of all ages. His science programs can be heard at noon on alternate Tuesdays on KVMR-FM (89.5).

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