The increased use of vehicles associated with back-to-school traffic has necessitated the season's first Air Alert to run from Monday to Wednesday.

In order to prevent the San Joaquin Valley air basin from exceeding federally-set one-hour ozone levels, air district officials urge residents to reduce their driving, refrain from idling their vehicles and to avoid the use of drive-through services.

According to the San Joaquin Valley Air Pollution Control District, about 80 percent of the Valley's smog level is caused by vehicle use, and back-to-school week increases the impact, particularly when combined with high temperatures and stagnant air flow.