The Effect of Wood Smoke on HealthBy Armeda Ferrini, Ph.D.
When people talk of wood stoves and fireplaces, everyone seems to have an opinion. “I have been burning wood in my home for 30 years and I feel fine!” “Hey, why pick on wood smoke – why not get the farmers to stop burning their rice stubble?” “Everyone knows that cars produce lots more pollution that our wood stoves!” “I need to burn because that is how I heat my home and wood is plentiful and cheap around here.” I love to see a good crackling fire, feel the warmth and the smell of wood smoke – it reminds me of good times.” Even though wood burning is a natural process, the smoke it produces contains very fine particles and many types of toxic gases that are known to be hazardous to our health. The extent of damage from wood smoke depends on the age and health of the person breathing it. The component of wood smoke that is most harmful is fine particulate matter, called PM2.5, measuring only 2.5 microns. For comparison, a human hair measures about 60 microns. These particles are so tiny that they reach the smallest airways and it is difficult for the lungs to dispel them. They damage our lung tissue and increase the risk of pneumonia, bronchitis and asthma, particularly among children and elders. These fine particles also enter the bloodstream and inflame our blood vessels, increasing cardiovascular disease risk, particularly among older people. It is documented that the number of hospital admissions and premature deaths are increased with the increase in wood-burning in a community. Further, research has found wood smoke can cause a significant increase of hospital admissions for respiratory problems among children. In Butte County, residential wood stoves and fireplaces are the biggest source of fine particle pollution. As expected, the highest concentration of wood smoke occurs from late November through January. In winter 2008-2009, residential fuel burning was responsible for 47 percent of all PM2.5 in the air. In contrast, during that same time period, managed burn in Butte County emitted 14 percent, agriculture was responsible for 4 percent, and automobiles, 4 percent. In addition to fine particulate matter, wood smoke also contains several toxic gaseous pollutants, many of which are carcinogens: for example, carbon monoxide, benzene, nitrogen dioxide, formaldehyde. Experts are also concerned with the health effects of many types of polycyclic aromatic hydrocarbons - widespread pollutants found in wood smoke - as many of those are also known carcinogens. Unfortunately, our valley location makes wood smoke a greater problem because the air may become still in the winter, allowing the pollutants to remain in many neighborhoods for days instead of being swept away by the wind. Studies report that up to 70 percent of smoke from chimneys can re-enter a home or neighboring residences. Butte County generally has from 25-28 bad air days each winter, violating the PM2.5 standards of the Clean Air Act. Because of this, the district has until 2012 to develop and implement a plan to reduce the PM2.5 air pollution or it may face sanctions that could include the loss of federal highway funds. But it is difficult to convince individuals to consent to mandatory restrictions on residential fuel burning to meet the federal standards. At the September meeting, the Butte Air Quality Management District proposed a mandatory curtailment of residential wood burning on projected bad air days for Butte County residents. Homes with no other heat source were to be excluded. Even though all board representatives from Chico voted “yes,” the proposal was rejected by board members representing other communities in Butte County and was not adopted. However, the Chico City Council is now working on a plan to ban residential wood burning within the city limits on poor air quality days. Since mandatory curtailment of wood burning on bad air days did not pass in Butte County, the district has implemented the voluntary Check Before You Light program, effective November 1st. The District asks that residents not use their woodstove or fireplace on a poor air quality day, when advisories are issued. See the box, “What you can do to reduce your health risk,” for ways to learn of the advisories. Each of us should regularly monitor the air quality in Butte County by checking the advisories, particularly during the winter months and wildfire season. Many counties within California have implemented restrictions on residential wood-burning on days when particulate matter pollution is expected to be high with much success on improving the air quality and their residents’ health. A recent study conducted at Fresno State concluded that the mandatory wood-burning ordinance passed in the San Joaquin Valley Unified Air Pollution Control District in 2003 significantly reduced small particulate air pollution, reduced premature deaths in that county and saved the residents millions of dollars in health care costs. Mandatory restrictions, local grants awarded to individuals to replace inefficient wood stoves and federal tax rebates on low emission wood stoves can substantially reduce the health hazards of wood smoke: respiratory and cardiovascular illnesses, hospitalizations and premature deaths. References
Armeda Ferrini, Ph.D. is a retired professor from the Department of Health and Community Services, California State University, Chico. She is a member of the BEC Board of Directors. From the Fall 2009 issue of the Environmental News. |