What causes these gases (including carbon monoxide) to build to dangerous levels?
Harmful build-ups of these gases can occur when: exhaust from combustion equipment is not properly vented or used,is not in good working order and is not regularly inspected for safe operation. Some homes may have a problem with “backdrafting.” That’s when the air pressure inside the home is less than the air pressure outside, causing combustion by-products from furnaces, water heaters, fireplaces and similar equipment to spill back into the room rather than being vented outside. (Sometimes flue gases can be drawn back into the home when several sources are being exhausted at once.) Backdrafting can also occur when natural draft appliance exhaust is pulled back into the house by mechanical ventilation-like a down-draft kitchen power vent. Tobacco smoking inside home also contributes. Q: How can I determine if combustion pollutants are affecting my health? A: They may be the culprit if fuel-fired combustion appliances are being used and only when you’re inside the home and the symptoms
