Continued exposure to high levels of carbon monoxide can cause collapse, unconsciousness, and, in extreme cases, death. Nitrogen dioxide can cause eye, nose, and throat and respiratory tract irritation. Prolonged exposure has been shown to lower resistance to respiratory infection and can be damaging to respiratory tissue. Sulfur dioxide is particularly threatening to people with asthma, in whom it can constrict the airways leading to and from the lungs, making breathing difficult. People with lung disease and allergies may also have adverse reactions to sulfur dioxide fumes.
Sulfur dioxide can also cause irritation of skin and eyes.
Indoor air contamination by combustion pollutants is a significant health problem. Harmful combustion pollutants produced by fuel-burning devices can reach unsafe levels. Proper ventilation is important. All fuel-burning devices need air in order to burn properly. In addition, if exhaust pipes, chimneys, or other ventilation systems are clogged or cracked, deadly quantities of carbon monoxide can leak into a building.