FRESNO  (AP) — Air quality officials are warning San Joaquin Valley residents of potential health hazards due to increasing ozone levels and smoke from lingering wildfires.

The San Joaquin Valley Air Pollution Control District issued an air alert — the second this year — on Monday for San Joaquin, Stanislaus, Merced, Madera, Fresno, Kings and Tulare counties and parts of Kern County.

Officials advise people to reduce prolonged exposure to the air and strenuous activities.

High ozone levels also put the Valley at risk for exceeding the 1-hour federal ozone standard, which can trigger an annual $29 million federal penalty, paid by an assessment on businesses and through a $12 annual vehicle registration fee for drivers from Stockton to Bakersfield.

The warning is in effect through Wednesday evening.