The state’s environmental agency has declared today as the first Ozone Action Day of the season for the Longview/Tyler area.

The declaration by the Texas Commission on Environmental Quality indicates conditions will be optimal today for the formation of ground-level ozone, or smog.

Residents are asked to limit certain activities to the cooler portions of the day. Those include mowing or operating any two-stroke engines — such as landscaping equipment — filling gas tanks, driving and washing clothes.

The agency recommends people travel on foot or by bicycle, take lunch to work and avoid drive-through lanes. Keeping a vehicle properly tuned also helps cut emissions.

Ozone forms when volatile organic compounds, such as those in fuels, solvents and pesticides, combine with heat and nitrogen oxide released from local smokestacks. The ozone season runs roughly from Memorial Day through Labor Day.