STAinNC member Alan Stahler addressed the Nevada City City Council during Wednesday night’s meeting. His comments certainly helped to persuade the Council to unanimously approve the resolution which calls for a regional air quality summit to address concerns that Sacramento pollution has created health problems for western Nevada County.

His statement follows:

OZONE: Presentation to Nevada City City Council

The ordinary, garden-variety oxygen we breathe is a very simple molecule, just two oxygen atoms glued together. But 25 miles or so over our heads, there’s another type of oxygen molecule, an oddball molecule made of three oxygen atoms glued together. Triatomic oxygen is ozone, and it’s good stuff: it intercepts ultraviolet radiation from the sun that would otherwise turn us to toast.

Twenty-five miles up: good ozone. Unfortunately, there’s ozone lurking here at the surface, too.

Ozone is very good at stealing the electrons that glue molecules together – steal their electrons, and molecules fall apart. When rubber molecules fall apart, your tires crack; when molecules in your body fall apart, you grow old.

Cars and trucks and power plants don’t put ozone into the air, but they pump out the ingredients – the “ozone precursors” – that, cooked in the sun, make ozone.

We all learned in kindergarten that you could make one color by mixing two others: blue and yellow make green.

You can do the same trick backwards: Starting with white light, you can make a color by subtracting other colors from it.

Look out over the Sacramento Valley as you’re racing down I-80 and there’s often a red-brown haze floating over the city. The valley’s air is rich in molecules of nitrogen dioxide – molecules that suck the blue and violet and ultraviolet out of white light – which makes it look red.

The energy of that missing light must go somewhere … it makes the molecules of nitrogen dioxide fall apart … and from those broken molecules come the atoms needed to turn ordinary oxygen into ozone.

But only while the sun is shining. When the sun goes down, ozone production stops. When the sun goes down, the ozone level in the valley begins to fall. Some of the same molecules that go into making ozone during the day go into breaking ozone molecules at night, when there’s no blue or violet to absorb.

Here in the foothills, we don’t have nearly as much traffic as they have in the valley, so we don’t produce nearly as much of the ozone precursors to break apart our ozone at night. When the sun goes down, foothill ozone levels may go down, but they don’t go as low as they do in the valley.

It’s counterintuitive, but, 24/7, we in the foothills have a worse ozone problem than do the urban areas – the Bay Area and Sacramento – that export their pollution to us.

We in the foothills are used to thinking of ourselves as being upslope from the valley … upstream from the cities … but we’re also downwind … and that’s why we have a problem with our air.

Save-The-Air in Nevada County has begun monitoring ozone levels around the county, to complement the work being done by the local air management district. We’re also comparing the air indoors and out, because, when ozone levels climb, we’re warned to avoid exercise and to stay indoors –to “shelter in place.”

Ozone reacts with all sorts of chemicals that float in the air of our homes. The good news is that this brings the ozone level down. The bad news is that some of the products of those reactions are more toxic than ozone itself.

Current plans call for Sacramento to clean up it air by 2013 … but new plans are in the works, with a new deadline: 2024,

That’s a long time for us to hold our breath.