Carbon monoxide

Carbon monoxide, known as the silent killer, is an indoor pollutant that becomes more of a hazard as winter approaches.

"Americans have become acutely aware of indoor environmental pollutants," says Phyllis Adams, associate professor of agricultural and extension education at Penn State's College of Agricultural Sciences. "Carbon monoxide can be a major hazard in the winter as homeowners start turning on heating systems and gas appliances."

Carbon monoxide reacts with the hemoglobin in blood, reducing the body's capacity to distribute oxygen throughout the body. In high concentrations, it will cause unconsciousness and death.

Carbon monoxide is one of the deadliest indoor pollutants because it is colorless and odorless and can build up concentrations within a single room or throughout the entire house. The symptoms of low-level concentrations -- fatigue, dizziness, headaches and nausea -- often are mistaken as individual maladies.

"People often don't read the clues properly. You assign the headache to a stressful day. You assign the dizziness to too little coffee," Adams says. "You go to bed in this polluted environment to get better, and if you're lucky, you'll wake up in the morning."

Adams says carbon monoxide is produced by combustion, particularly the burning of wood and fossil fuels. Such products as woodstoves, fireplaces, chimneys, stoves, furnaces, water heaters and kerosene or gas space heaters can become deadly if homeowners are not vigilant.

Adams says every homeowner should invest in carbon monoxide detectors (which are very different than smoke detectors). She recommends placing one in each bedroom at a minimum.

Homeowners can check for carbon monoxide themselves, Adams says, by careful observation. If any gas-operated appliance burns with a yellow flame, the appliance needs an adjustment. "If the flame isn't blue, it's time to call for service," Adams says.

Woodstoves and fireplaces also are carbon monoxide producers, and Adams says only heating professionals or masonry contractors should check for possible leaks. "Homeowners can check for creosote buildup and bird and animal nests," she says.

Adams says that homeowners should ensure that fireplaces have a proper air draft. In addition, all open fireplaces should have glass fire doors. "Make sure you burn 100 percent wood products. Never burn laminated wood or pressure-treated wood, because they contain hazardous chemicals," Adams says.

Kerosene heaters also can be dangerous polluters if used improperly. Adams says such space heaters must use only the proper fuel and should be strictly maintained by the homeowner.

"Kerosene heaters must be vented to an exterior air source," Adams points out. "Opening one window isn't going to help unless there is a cross draft. You're really polluting your environment unless there is a good indoor-outdoor air exchange."

Adams says ventilation and proper maintenance are the keys to reducing carbon monoxide risk. She suggests that homeowners check appliances yearly, adjusting them when necessary. She also recommends making room in the budget for carbon monoxide detectors in every room.

"It can be a big expense, but how can you put a value on a human life?" she says.