It's been a tough summer and fall for local air quality, thanks to lung-choking smoke drifting into the valley from wildfires up and down the state.

Valley air officials are asking Bakersfield-area residents to refrain from adding to the problem by burning their own wood fires in hearth and home.

"We’re once again asking San Joaquin Valley residents to continue the cooperation that made last winter the cleanest on record," said Samir Sheikh, executive director and air pollution control officer at the San Joaquin Valley Air Pollution Control District.

"To protect the health of their families and their neighbors, we encourage residents to not burn wood this winter and instead choose to upgrade to natural gas devices through our grant program," he said.

This week marks the beginning of the air district's annual Check Before You Burn program, which runs from Nov. 1 through the end of February, and whose goal is to gain valley residents' cooperation in protecting public health and improving wintertime air quality.

The regulations determine when residential wood burning will add dangerous levels of particulate matter to the valley's air, and regulates the use of wood-burning devices on those days. Wood-burning forecasts are issued by county or region each day.

Residents with no natural gas service or other form of heat are exempt from the rule, but only for indoor heating.

"Unlike wildfires, we have control over how we choose to heat our homes," said the district's Chief Communications Officer Jaime Holt. "It is critical to public health that we do not add to the unhealthy air quality created by wildfires."

So-called "Hot Spot" areas, including the valley portion of Kern County, have more stringent controls than some other valley counties because they historically have poorer air quality.

This year, as the program kicks off amid the worst wildfire season in California history and fires continue to impact valley air quality, air officials say residents should expect curtailments to begin early and continue through the 120-day period — with few "burn days" allowed, days that are referred to as "burning discouraged."

According to the district, last winter in the valley portion of Kern, there were only 22 "Burning discouraged" days. The other 98 were either "No burning for all" or "No burning unless registered."

That means, for the vast majority of residents, only about 18 percent of last year's 120-day Check Before You Burn season was it OK to burn.

Sure, those have clean-burning devices that are registered with the district may burn on more days, but the percentage is tiny. According to the district, the number of registered wood burning devices is only 1,514 valley wide. In Kern, the number is practically irrelevant at 84.

Check Before You Burn protects public health through the reduction of harmful PM 2.5, which are particulate matter 2.5 microns and smaller, so small they can become lodged in the lungs — and even migrate into the blood stream.

Residential wood burning is one of the valley’s largest sources of wintertime PM 2.5 emissions and is shown to have a direct effect, especially on neighborhood air quality.  If you can smell the smoke from your neighbor's fire — or your own — you are inhaling smoke, air officials warn.

Reporter Steven Mayer can be reached at 661-395-7353. Follow him on Facebook and on Twitter: @semayerTBC.