The 15th season of the Valley's residential wood-burning program ended Feb. 28 with more days of prohibited or restricted burning than last year, but a lower level of harmful particulate matter in the air.
The level of PM 2.5 emissions is at an all-time low, according to the San Joaquin Valley Air Pollution Control District. However, this past winter the Valley experienced a number of weeks of high pressure and atmospheric stagnation which lead to exceptionally high PM 2.5 concentrations. Additionally, the Thomas Fire, California's largest wildfire to date, affected the Valley's air quality in December.
Check Before You Burn runs each winter from November through February and helps minimize the build-up of harmful fine particle pollution in the Valley. The District issues a wood-burning declaration daily for every county in the air basin that determines what, if any, residential wood-burning devices may be used.
According to the Air District, smoke from residential wood burning constitutes the largest source of dangerous particulate emissions during winter months. Fine particulate matter can increase the risk of lung disease, respiratory illness, heart attacks and stroke.
Stanislaus County had 49 days of burning prohibited unless it was with a registered clean device. This was an increase from the 30 days issued in the 2016-17 season. There were two days this season in which burning was restricted for all devices.
This season also saw an increase in the number of violations issued by the Air District. In Stanislaus County there were 73 violations issued for 2017-2018, while the previous season saw 44 violations issued.
Given the Valley's geography and topography, the high-pressure acts like a lid over the mountains surrounding the region and even low amounts of emissions eventually build to high concentrations. Despite the poor dispersion this winter, the peak levels of PM 2.5 were still lower than what the Valley is used to seeing in the same conditions, reflecting the progress in emissions reductions the Valley has achieved over last two decades.
"We are moving in the right direction thanks to the cooperation of Valley residents and stakeholders and their investments in cleaner devices," said Seyed Sadredin, the District's executive director and air pollution control officer. "These improvements would not be possible without the success of the District's comprehensive control strategy which includes Check Before You Burn, as well as the District's attainment planning efforts and robust incentive programs, like Burn Cleaner which provides grants for the purchase of cleaner devices."
Beginning Thursday, the District will no longer issue a daily residential wood burning status for each county. While no formal burning restrictions will be in place until Nov.1, the District discourages residential wood burning.
Valley residents wanting to switch out older wood-burning devices for a cleaner model can still take advantage of the District's Burn Cleaner incentive program which provides $1,000 for certified wood or pellet inserts, freestanding stoves or natural gas inserts or $2,500 for eligible low-income applicants for all devices. An additional $500 is available to all applicants for the installation costs on a natural gas device. Visit www.valleyair.org/burncleaner for program guidelines.