Angina pectoris is chest pain associated with impaired oxygen flow to the heart and may occur at COHb levels between 2.5 and 4.9 percent in cardiac patients. In healthy individuals decreased vigilance, confusion and disorientation, behavioral, and central nervous system effects occur at COHb levels between 4 and 6 percent. Remember that as symptoms of CO poisoning increase, you may become confused and less capable of making decisions that could save your life. These standards are based on preventing adverse effects in individuals with cardiac or vascular disease and in exercising humans. Seattle, Spokane, Yakima, and parts of Pierce and Thurston Counties may exceed these values during heavy traffic periods and when inversions occur.
Inversions occur when cold stable air layers form above warmer air.
This traps pollutants beneath the stable air layer. As outdoor levels increase due to peak traffic times, or because of an inversion, indoor levels will rise proportionately. If indoor sources of CO exist, indoor levels will be higher than those outside. Avoid strenuous physical activity during peak traffic times, in high volume traffic areas, and during inversions . Heating season is a time of particular concern with regard to CO exposure.