It's that time of year again, and wildfire smoke primarily coming from lightning-caused fires that broke out last week in far Northern California is now starting to impact air quality in the Bay Area.

AQI readings in the North Bay were already hitting the yellow zone Monday morning, with smoke haze and even the smell of smoke beginning to move into the region. The EPA's Fire and Smoke Map showed yellow or "moderate" air impacts throughout Marin, Sonoma, Napa, and Solano counties, with a couple of yellow readings appearing in coastal San Francisco as well. Numbers from the Bay Area Air Quality Management District (BAAQMD) show air quality declining Monday morning in Sebastopol and San Rafael, as well as in West Oakland.

A larger view of the map shows the fires that are producing much of this smoke, including the SKU August Lightning Complex fires in Siskiyou County, and the Happy Camp Complex which is also in Siskiyou County, and which has grown to 10,500 acres. Bands of smoke can be seen moving in off the Pacific, and these will eventually reach the San Francisco Peninsula today as well.

The BAAQMD said in a statement Monday that AQI levels are not likely to reach the "unhealthy" range in the Bay Area, but they still urged caution and advised anyone who can smell smoke to keep doors and windows closed if possible. They also advised anyone driving to turn their air conditioning onto re-circulate mode.

"Smoke can irritate the eyes and airways, causing coughing, a scratchy throat and irritated sinuses," the BAAQMD said. "Elevated particulate matter in the air can trigger wheezing in those who suffer from asthma, emphysema or COPD."

The Happy Camp Complex fires began on August 16 and consists of about 20 small fires which are considered 0% contained as of Monday morning. That complex of fires has destroyed nine structures and claimed one life.

Also currently burning to the north and just 15% contained is the SRF Lightning Complex fires in Humboldt County, which have burned over 4,000 acres.

The SKU August Lightning Complex began with lightning in Klamath National Forest on Tuesday, August 15. That group of fires is now 90% contained after burning just under 900 acres. The complex was initially referred to as the Head Fire and had been estimated at 3,000 acres last week, but that estimate appears to have been corrected.

There is also a large fire burning in Santa Barbara County, the Plant Fire, which has burned over 5,500 acres and is now 60% contained.

You can monitor the hourly changes to the AQI in your area here.