Summer Ozone season kicks off

Here is the obligatory pollution story:

Maricopa County’s ozone season starts today with a fresh burst of heat and sunlight, two key ingredients needed for unhealthful levels of the smog to form.

Temperatures could rise to nearly 100 degrees today as a strong high-pressure system creates the ideal conditions for ground-level ozone. The other elements – vehicle exhaust, power-plant emissions, gasoline, paint and industrial solvents – are always in abundant supply.  Read more…

My gripe? While I agree that vehicle exhaust is always in abundant supply, I don’t imagine power plants contribute any significant amount of pollution to the Phoenix area. The closest big power plant is Palo Verde nuke which is by definition smog-free. There are a bunch of small-scale power plants within the valley but they tend to be natural gas fired, which is very very clean smog-wise. The nearest big coal plant, which are among other pollutants very smoggy are hundreds (?) of miles away.

I wonder how much of smog is contributed other than from vehicle exhaust (and fueling)?? I doubt very much.