California Air Resources Board

SACRAMENTO - Reductions in both fine particulate pollution (PM 2.5) and cardiovascular hospitalizations were seen in the San Joaquin Valley after a ‘Check-Before-You-Burn’ regulation was fully implemented in that air basin, Air Resources Board research has found.

ARB’s research examined the effectiveness of San Joaquin Valley Air Pollution Control District Rule 4901, fully implemented in 2003, at reducing PM2.5 and cardiovascular hospitalizations in the valley air basin. During winter, PM2.5 is a health problem in the San Joaquin Valley – and many parts of California. Wood burning regulations, like Rule 4901, are in effect in many air districts during the burn season from Nov. 1 through February to reduce emissions of PM2.5 and carbon monoxide from residential wood burning.

Cold and still winter weather can cause wood smoke pollution to become trapped close to the ground and build up to unhealthy levels, triggering air district rules that curtail residential wood burning to protect public health.

“ARB’s research provides evidence that these ‘check-before-you-burn’ programs, combined with public education, are helping to reduce harmful wintertime air pollution and protect public health,” Chair Mary D. Nichols said.

The San Joaquin Valley’s Rule 4901 requires mandatory curtailment of residential wood burning when air quality is forecast to be poor – an air quality index of 150 or greater during the wood burning season. The ARB study found that after the implementation of the wood burning regulation in the San Joaquin Valley in the winter:

• PM2.5 was reduced by 12% basin-wide and by 11% and 15% in rural and urban regions of the basin, respectively.
• Larger, coarse particulate matter was reduced 8% basin-wide and in rural (7%) and urban (11%) areas of the basin.
• The number of hospital admissions for all types of cardiovascular disease in adults 65 and older dropped by 7% basin-wide. In addition, hospitalizations for ischemic heart disease, a specific type of cardiovascular disease often known as coronary artery disease, dropped by 16% basin-wide.  Reductions in rural areas were even higher for both categories of hospital admissions.

The San Joaquin Valley historically has had some of the worst air quality in the nation, and solid fuel combustion – burning wood, manufactured logs and pellets in fireplaces and wood stoves -- has been identified as the largest individual source of particulate matter during winter months. 

Emitted when solid fuels, such as wood, are burned, PM2.5 can penetrate deep into the lungs and have been linked to serious health impacts. Health studies have found that long-term exposure to PM2.5 can be linked to premature death from heart and lung diseases and reduced lung function growth in children.

The San Joaquin Valley needs to address all major sources of pollution to meet federal health-based air quality goals and therefore must continue to address the problem of residential wood burning. It is estimated that wood burning in the valley contributes to 16 tons per day of smoke, soot and ash. Besides the San Joaquin Valley, other air districts also have wood burning rules. In fact, neighboring Sacramento Metropolitan Air Quality Management District (all of Sacramento County) in recent years achieved the federal PM2.5 standard due in large part to emissions reductions from the public’s compliance with its Check Before You Burn program. The largest air districts, South Coast, Bay Area and Sacramento Metro, in addition to the San Joaquin Valley, all have mandatory no-burn restrictions during the winter months. Other districts have voluntary programs.

For more information about ARB’s research paper, click here.

For information on air district wood-burning rules, see FAQs:

• San Joaquin Valley
• South Coast
• Sacramento Metro
• Bay Area

For additional information, see the California Air Resources Board Wood Burning Handbook.