Health Problems Caused By Other Combustion Products
(Stoves, Space Heaters, Furnaces, Fireplaces)
Key Signs/Symptoms
  • dizziness or headache
  • confusion
  • nausea/emesis
  • fatigue
  • tachycardia
  • eye and upper respiratory tract irritation
  • wheezing/bronchial constriction
  • persistent cough
  • elevated blood carboxyhemoglobin levels
  • increased frequency of angina in persons with coronary heart disease
Diagnostic Leads
  • What types of combustion equipment are present, including gas furnaces or water heaters, stoves, unvented gas or kerosene space heaters, clothes dryers, fireplaces? Are vented appliances properly vented to the outside?
  • Are household members exhibiting influenza-like symptoms during the heating season? Are they complaining of nausea, watery eyes, coughing, headaches?
  • Is a gas oven or range used as a home heating source?
  • Is the individual aware of odor when a heat source is in use?
  • Is heating equipment in disrepair or misused? When was it last professionally inspected?
  • Does structure have an attached or underground garage where motor vehicles may idle?
  • Is charcoal being burned indoors in a hibachi, grill, or fireplace?
Remedial Action
Periodic professional inspection and maintenance of installed equipment such as furnaces, water heaters, and clothes dryers are recommended. Such equipment should be vented directly to the outdoors. Fireplace and wood or coal stove flues should be regularly cleaned and inspected before each heating season. Kitchen exhaust fans should be exhausted to outside. Vented appliances should be used whenever possible. Charcoal should never be burned inside. Individuals potentially exposed to combustion sources should consider installing carbon monoxide detectors that meet the requirements of Underwriters Laboratory (UL) Standard 2034. No detector is 100% reliable, and some individuals may experience health problems at levels of carbon monoxide below the detection sensitivity of these devices.
Comment
Aside from environmental tobacco smoke, the major combustion pollutants that may be present at harmful levels in the home or workplace stem chiefly from malfunctioning heating devices, or inappropriate, inefficient use of such devices. Incidents are largely seasonal. Another source may be motor vehicle emissions due, for example, to proximity to a garage (or a loading dock located near air intake vents).
A variety of particulates, acting as additional irritants or, in some cases, carcinogens, may also be released in the course of combustion. Although faulty venting in office buildings and other nonresidential structures has resulted in combustion product problems, most cases involve the home or non-work-related consumer activity. Among possible sources of contaminants: gas ranges that are malfunctioning or used as heat sources; improperly flued or vented fireplaces, furnaces, wood or coal stoves, gas water heaters and gas clothes dryers; and unvented or otherwise improperly used kerosene or gas space heaters.
The gaseous pollutants from combustion sources include some identified as prominent atmospheric pollutants-carbon monoxide (CO), nitrogen dioxide (NO2), and sulfur dioxide (SO2).
Carbon monoxide is an asphyxiant. An accumulation of this odorless, colorless gas may result in a varied constellation of symptoms deriving from the compound's affinity for and combination with hemoglobin, forming carboxyhemoglobin (COHb) and disrupting oxygen transport. The elderly, the fetus, and persons with cardiovascular and pulmonary diseases are particularly sensitive to elevated CO levels. Methylene chloride, found in some common household products, such as paint strippers, can be metabolized to form carbon monoxide which combines with hemoglobin to form COHb. The following chart shows the relationship between CO concentrations and COHb levels in blood.
Tissues with the highest oxygen needs-myocardium, brain, and exercising muscle-are the first affected. Symptoms may mimic influenza and include fatigue, headache, dizziness, nausea and vomiting, cognitive impairment, and tachycardia. Retinal hemorrhage on funduscopic examination is an important diagnostic sign, 19 but COHb must be present before this finding can be made, and the diagnosis is not exclusive. Studies involving controlled exposure have also shown that CO exposure shortens time to the onset of angina in exercising individuals with ischemic heart disease and decreases exercise tolerance in those with chronic obstructive pulmonary disease (COPD). 20
Note: Since CO poisoning can mimic influenza, the health care provider should be suspicious when an entire family exhibits such symptoms at the start of the heating season and symptoms persist with medical treatment and time.
% COHb in blood Effects associated with this COHb level
80 Death a
60 Loss of consciousness; death if exposure continues a
40 Confusion; collapse on exercise a
30 Headache; fatigue; impaired judgment a
7-20 Statistically significant decreased maximal oxygen consumption during strenuous exercise in healthy young men b
5-17 Statistically significant diminution of visual perception, manual dexterity, ability to learn, or performance in complex sensorimotor tasks (such as driving) b
5-5.5 Statistically significant decreased maximal oxygen consumption and exercise time during strenuous exercise in young healthy men b
Below 5 No statistically significant vigilance decrements after exposure to CO b
2.9-4.5 Statistically significant decreased exercise capacity (i.e. shortened duration of exercise before onset of pain) in patients with angina pectoris and increased duration of angina attacks b
2.3-4.3 Statistically significant decreased (about 3-7%) work time to exhaustion in exercising healthy men b
Source: a U.S. EPA (1979); b U.S. EPA (1985)
Nitrogen dioxide and sulfur dioxide act mainly as irritants, affecting the mucosa of the eyes, nose, throat, and respiratory tract. Acute SO2-related bronchial constriction may also occur in people with asthma or as a hypersensitivity reaction. Extremely high-dose exposure (as in a building fire) to NO2 may result in pulmonary edema and diffuse lung injury. Continued exposure to high NO2 levels can contribute to the development of acute or chronic bronchitis.
The relatively low water solubility of NO2 results in minimal mucous membrane irritation of the upper airway. The principal site of toxicity is the lower respiratory tract. Recent studies indicate the low-level NO2 exposure may cause increased bronchial reactivity in some asthmatics, decreased lung function in patients with chronic obstructive pulmonary disease, and an increased risk of respiratory infections, especially in young children.
The high water solubility of SO2 causes it to be extremely irritating to the eyes and upper respiratory tract. Concentrations above six parts per million produce mucous membrane irritation. Epidemiologic studies indicate that chronic exposure to SO2 is associated with increased respiratory symptoms and decrements in pulmonary function.21 Clinical studies have found that some asthmatics respond with bronchoconstriction to even brief exposure to SO levels as low as 0.4 parts per million.22
References
19  Samet, J.M., Marbury, Marian C., and Spengler, J.D. "Health Effects and Sources of Indoor Air Pollution, Part I." American Review of Respiratory Disease 1987, 136:1486-1508.
20  American Thoracic Society. "Report of the ATS Workshop on Environmental Controls and Lung Disease, Santa Fe, New Mexico, March 24-26, 1988." American Review of Respiratory Disease 1990; 142:915-39.
21  Lipsett, M. "Oxides of Nitrogen and Sulfur." Hazardous Materials Technology 1992; 000:964-69.
22  U.S. Environmental Protection Agency. "Review of the National Ambient Air Quality Standard for Sulfur Oxides: Updated Assessment of Scientific and Technical Information; Supplement to the 1986 Staff Paper Addendum (July 1993)."