Page 414 - Fundamentals of Air Pollution 3E

368 22. Air Quality Criteria and Standards

TABLE 22-1
U.S. Ambient Air Quality Criteria for Carbon Monoxide
Percent of
carboxyhemoglobin
(CoHb) in blood Human symptoms associated with this CoHb level
80 Death
60 Loss of consciousness; death if exposure is continued
40 Collapse on exercise; confusion
30 Headache, fatigue; judgment disturbed
20 Cardiovascular damage; electrocardiographic abnormalities
5 Decline (linear with increasing CoHb level) in maximal oxygen
uptake of healthy young men undergoing strenuous exercise;
decrements in visual perception, manual dexterity, and
performance of complex sensorimotor tasks
4 Decrements in vigilance (i.e., ability to detect small changes in one's
environment that occur at unpredictable times); decreased exercise
performance in both healthy persons and those with chronic
obstructive pulmonary disease
3-6 Aggravation of cardiovascular disease (i.e., decreased exercise
capacity in patients with angina pectoris, intermittent claudication,
or peripheral arteriosclerosis)
Sources: Henderson, Y., and Haggard, H. W., "Noxious Gases." Chemical Catalog Co., New
York, 1927; and U.S. Environmental Protection Agency, Research Triangle Park, NC; Air
Quality Criteria for Carbon Monoxide EPA/600/8-90/045F, December 1991.

II. CONVERSION OF EFFECTS DATA AND CRITERIA
TO STANDARDS

In developing air pollution cause-effect relationships, we must be con-
stantly on guard lest we attribute to air pollution an effect caused by some-
thing else. Material damage due to pollution must be differentiated from
that due to ultraviolet radiation, frost, moisture, bacteria, fungi, insects,
and animals. Air pollution damage to vegetation has to be differentiated
from quite similar damage attributable to bacterial and fungal diseases,
insects, drought, frost, soil mineral deviations, hail, and cultural practices.
In the principal animal disorder associated with air pollution, i.e., fluorosis,
the route of animal intake of fluorine is by ingestion, the air being the
means for transporting the substance from its source to the forage or hay
used for animal feed. However, the water or feed supplements used may
also have excess fluorine. Therefore, these sources and disease states, which
may have symptoms similar to those of fluorosis, must be ruled out before
a cause-effect relationship can be established between ambient air levels
of fluorine and fluorosis in animals. Similarly, there are many instances of
visibility reduction in the atmosphere by fog or mist for which air pollution
is not a causative factor.