‘Spare the Air’ alert issued through Saturday for Sacramento. Wildfire smoke enters valley

Air quality managers in Sacramento said that Friday and Saturday would be the fifth and sixth “Spare the Air” days in 2021 due to high temperatures, a strong inversion layer and light winds.

An air quality index reading of 136 is expected Friday for the Sacramento region, according to the Sacramento Metropolitan Air Quality Management District. Saturday’s AQI is forecast to be 133. Officials issue alerts when the AQI is 126 or higher, which is considered unhealthy for sensitive groups.

The AQI was recorded as 140 on Thursday, the district said in a Friday update.

District spokeswoman Jamie Arno said there’s a strong inversion layer in the region, trapping heat and air pollution produced close to the ground. In this instance, she said, the pollution sits around and builds up.

Adding to that, the Sacramento region is forecast to see light winds under 5 mph. Arno said air pollution even with an inversion layer can be pushed out with a strong Delta breeze. However, with little wind, pollutants tend to linger.

Officials have also said the region is forecast to have highs near 100 degrees.

Residents are asked to cut back on driving and other activities that could increase pollution levels. The advisory also includes air districts for El Dorado, Placer and Yolo counties. Individuals with respiratory health conditions should look to limit their outdoor exposure.

Portable blowers should be put away as well.

On days when the AQI is above 101, the city of Sacramento prohibits the use all portable leaf blowers under an ordinance passed by the Sacramento City Council in November 2020. Officials say blowers contribute to dust emissions and gas exhaust and can worsen air quality levels.

Air quality managers issued back-to-back alerts on July 8 and 9 as a heat wave scorched the capital region. Back-to-back alerts were also issued last month during another heat wave. Only one alert was issued in 2020.

National Weather Service forecasts show temperatures trending upward to triple digits in Sacramento on Friday and then descending to the mid-90s early next week.

Wildfire smoke moving into the Sacramento Valley

In a potential new impact on air quality, smoke from the Dixie and nearby Fly fires made its way into the Sacramento Valley on Friday afternoon, the weather service’s Sacramento office said.

Smoke is heavier in areas north of Sacramento County. Cal Fire’s Nevada-Yuba-Placer Unit said in a social media post that “heavy drift smoke” from the Dixie Fire had entered the city of Auburn and the surrounding canyon.

The Folsom Fire Department had also told nearby residents in a social media post that the smoke visible in the city was from the Dixie Fire, rather than any active fires nearby.

Some parts of the capital region are warning residents about it. The Placer County interim health officer and Placer County Air Pollution Control District issued a joint air quality advisory through Sunday. Placer officials have said there’s a possibility of poor air quality conditions due to smoke from Northern California wildfires.

Courtney Carpenter, an NWS Sacramento meteorologist, said winds from the north are pushing smoke into the valley.

Until now, Sacramento has been largely spared from wildfire smoke as winds from the southwest pushed smoke into the eastern parts of the U.S., Carpenter said. But winds from the north have changed that.

It’s not clear how long the smoke will remain in the valley. According to Carpenter, the forecast is heavily dependent on fire activity, and it’s difficult to predict how much smoke the fires are producing.

The Dixie Fire is California’s largest wildfire this year, burning over 200 square miles on the border of Butte and Plumas counties.

This story was originally published July 22, 2021 at 1:12 PM.