Most air pollution is easy to see – it’s that ugly brown haze that hangs in the sky. It comes from a variety of sources: automobiles, dust from roadways and construction sites, wood stoves, and forest fires, including both wildfires and prescribed burns to reduce the buildup of dead wood (hazard fuels reduction). Air pollution can have wide ranging effects on our health, the environment and overall quality of life. The air quality at Lake Tahoe is generally quite good. However, due to the geography of this region, the Tahoe Basin is more sensitive to negative impacts than most other areas. Winter weather conditions - cold nights, with little wind - often cause smoke and other air pollution to accumulate close to the ground overnight. With little or no wind, temperature inversions can occur – warm layers act as a lid over the cold air, trapping smoke and other pollution near the surface of the land and Lake.
Air pollution in the Lake Tahoe Basin originates from both in-Basin (i.e. local) and out-of-Basin sources. Within the Tahoe Basin, automobile exhaust and road dust from vehicles and smoke from residential wood burning stoves and fireplaces are among the primary contributors to local air pollution problems. Pollution from automobiles (both exhaust and roadway dust) also impacts water clarity by traveling through the air and falling onto the Lake. Additionally, air pollution from nearby cities such as Sacramento and San Francisco is carried into the Tahoe Basin by the wind, primarily during the summer months. One way to reduce the air and water quality problems caused by automobiles is to limit the use of our personal vehicles. Consider walking, riding your bike, or using public transportation to cut down on the number of trips you take in your car. Organize your vehicle trips with multiple well thought-out stops in mind.
A noticeable though less frequent source of air pollution common at this time of year is prescribed fire (i.e. controlled burns). There is a delicate balance when it comes to prescribed fire, because while prescribed fire can cause air quality problems, forest hazard fuel reduction is necessary in order to protect communities from wildfire, and promote healthier forest conditions. In addition, long term, fuel reduction efforts could actually protect air quality by preventing large, out-of-control fires that “smoke out” the Basin for prolonged periods.
Prescribed fire, either broadcast burning (slow small intensity burns across forest floors) or pile burning, is used to help reduce the un-natural amounts of hazardous fuel in our forests. These controlled burns are only conducted on Air Resources Board approved “burn days,” after having undergone extensive planning to minimize air quality impacts, and after handwork to prepare the fuels beforehand. Broadcast burns support the natural fire regime our forests need and improve overall forest health in several ways. Pile burns are used to eliminate accumulations in the forest, and do not have any specific environmental benefit in themselves. Although there has been encouragement to complete more broadcast-type burning, such burns are more difficult to do, as they tend to generate smoke for more prolonged periods. With limited resources, and the significant need, pile burning is the most efficient method for dead wood (biomass) removal because it is the least expensive, allowing more acres to be treated than if funds have to pay for flammable materials to be collected and driven out of the Basin for disposal.
Where prescribed fire smoke is only an occasional source, neighborhood residential wood-burning is a continuous source of localized air pollution. Most wood heaters (woodstoves and fireplaces) release far more air pollution, indoors and out, than heaters using other fuels (such as natural gas). Woodsmoke significantly degrades the air quality and visibility in Tahoe, where many woodstoves and fireplaces are in use. Add to that frequent inversions during the colder months, and pollution is worsened. Therefore, another thing you can do to reduce air pollution is to replace your old wood-burning stove with a clean burning gas fireplace, or a new wood or gas stove or insert. Look for EPA approved models, which have higher heating efficiency – old wood stoves can waste 30% to 60% of your wood. New stoves generate the same amount of heat using much less wood. New wood stoves incorporate the latest and best technology available on transfer efficiency, and will provide more heat for your house and less for your flue! Burn two cords instead of three and get the same amount of heat. It will help pay for itself in fuel and cleaning savings. (Woodburning Handbook: How to Burn More Efficiently In Your Stove or Fireplace and Produce Less Air Pollution, California Air Resources Board).
To assist progress in the direction of higher efficiency heating technology, there is a provision that requires the removal of older non-conforming wood stoves when real estate is sold or transferred. For more information about preventing air pollution, contact Jennifer Quashnick, TRPA, (775) 588-4547, Ext. 278, visit http://www.trpa.org/ordinances/pdffiles/code91.pdf or request a free copy of the Woodburning Handbook.
The Lake Tahoe Report 006
Air Date: 2003.03.11
Video Segment: Reducing Air Pollution
Interviewees: Heather Segale (UNCE)