Environmental Engineering Reference
In-Depth Information
as well as other toxic pollutants may interfere with calcium flow into neurons,
thereby disrupting the learning process” in children.
71
The CDC guideline for blood lead level has been lowered to 10
µ
g/dl. This
will increase the number of children under age 6 at risk by 10 times according
to CDC estimates.
Carbon Monoxide Poisoning
Carbon monoxide poisoning is sometimes confused with food poisoning, as
nausea and vomiting are common to both. In carbon monoxide poisoning, the
additional symptoms include headache, drowsiness, dizziness, flushed complex-
ion, and general weakness, and carbon monoxide is found in the blood. Excessive
exposure results in reduced oxygen availability to the heart, brain, and muscles,
leading to weakness, loss of consciousness, and possible death. Persons with car-
diovascular diseases are very sensitive to carbon monoxide in low concentrations.
Carbon monoxide combines readily with blood hemoglobin to form carboxy-
hemoglobin (COHb), thereby reducing the amount of hemoglobin available to
carry oxygen to other parts of the body. Hemoglobin has a greater affinity for
carbon monoxide than for oxygen — about 210 to 1. Fortunately, the formation
of COHb is a reversible process. Death can occur when blood contains 60 to 80
percent COHb.
Carbon monoxide is an odorless, tasteless, and colorless gas. It is a product of
incomplete combustion of carbonaceous fuels. Poisoning is caused by leaks in an
automobile exhaust system; running a gasoline or diesel engine indoors or while
parked; unvented or defective kerosene, gas,
∗
fuel oil, coal, or wood-burning
space or water heater, gas range-oven, or gas-fired floor furnace; use of char-
coal grill indoors; clogged or leaking chimney or vent; inadequate ventilation
and fresh air for complete combustion; improperly operating gas refrigerator;
and incomplete combustion of liquefied petroleum gas in recreational and camp-
ing units. The indoor work environment (use of a fork lift or other motorized
equipment) may also be a hazardous source of carbon monoxide.
Motor vehicle exhausts are the principal source of carbon monoxide air pol-
lution; however, federal standards and emission controls on new automobiles
are reducing the ambient-air carbon monoxide levels. Room space heaters are a
major potential hazard indoors. Cigarette smoke is also a significant source of
carbon monoxide to the smoker.
Education of the public and medical care personnel, standards for appliances,
and housing code enforcement can reduce exposure and death from this poi-
soning. Homes in low-socioeconomic areas can be expected to have the highest
carbon monoxide levels.
Concentrations of 70 to 100 ppm carbon monoxide are not unusual in city
traffic. The federal ambient-air-quality standard maximum 8-hour concentration
is 10 mg/m
3
(9 ppm); the maximum 1-hour concentration is 40 mg/m
3
(35 ppm).
∗
Including methane, butane, and propane.
