OZONE has been found to be a substantial part of the oxidant characteristic of Los Angeles' smog. Since automobile exhaust gases are capable of forming ozone in the air, they are considered a definite cause of smog.
In studies reported here, ozone was produced in the laboratory and measured by rubber cracking and chemical tests. Exhaust gases from cruising and accelerating phases of automobile operation were irradiated to form ozone. Exhaust gas from idling and deceleration produced ozone photochemically after addition of NO2.