Residents in Simi Valley and other inland cities in Ventura County can expect unhealthful air this weekend, as temperatures stay warm and the air remains stagnant.
Air quality in Simi Valley is expected to reach 145 on the Pollutant Standard Index during the weekend, said Gary Arcemont, meteorologist with the Ventura County Air Pollution Control District.
Air is considered unhealthful when it reaches 100 by federal health standards. More stringent state standards say air is unhealthful when it measures 75 on the index.
Air quality in Ojai and other inland valleys is also forecast to be unhealthful.
The district issues a warning telling the elderly and children, as well as sensitive adults, to stay indoors when the index reaches 131 on the scale.