Effects of Carbon Monoxide on Health

Probably the largest group of studies relating to automobile emissions concerns the health effects of carbon monoxide. Breathing carbon monoxide increases the level of carboxyhemoglobin (COHb) in the blood, thus reducing the amount of free hemoglobin available for carrying oxygen to body tissues for normal activity.

The saturation of the blood with COHb is known to put a strain on the heart, as well as affecting performance on standardized tests (impaired coordination, inability to judge time, slowing down reaction time, and affecting mental abilities).

However, these effects have been demonstrated for relatively high levels of carbon monoxide in the air or (COHb in the blood). The critical question is whether the levels resulting from the emissions of mobile sources are sufficient to generate important health effects.

The health effects of total oxidants are hypothesized to be similar to those of carbon monoxide, although the detailed physiological mechanism, thought to be different, is not fully understood. Little work has been done on the health effects of the oxides of nitrogen or of hydrocarbons. What follows is a brief review of some of the studies concerning effects from air pollution related to mobile-source emissions.

Researchers have performed experiments with human subjects and rats to determine the effect of carbon monoxide on time perceptions. The ability of subjects to as certain whether a second tone lasted longer, shorter or for the same time compared with a previous tone (for small differences in duration of the tone) fell uniformly with the level of carbon monoxide breathed.

Although the error rate was closely related to the concentration (which ranged from zero to 250 ppm), the subjects suffered no noticeable physiological reactions to the carbon monoxide. Thence, even though the experiment appeared to isolate a subtle effect of exposure to carbon monoxide at low concentrations, it is not evident what the implications are for its effect on human behavior in the activities of daily life.

Other people have done research where they exposed subjects to carbon monoxide under experimental conditions and recorded physical data as well as performance on a driving simulator, and hand-steadiness and manual dexterity tests.

The most important finding was that an eight-hour exposure to 100 parts per million of carbon monoxide, resulting in COHb saturation of 11 percent to 13 percent, produced no impairment of performance in the tests studied in this select, healthy group of volunteers.

The tests chosen for investigation were those felt to be of practical significance in the performance of vocational endeavors and automobile driving, where significant impairment of visual or auditory acuity, coordination, reaction time, manual dexterity, or time estimation would be intolerable.

Without a doubt, air pollution as well as the thousand and one pollutants that are contained in them will definitely have an adverse effect on people’s health. There are concrete and real dangers of being exposed to air pollution. Armed with the knowledge of all of the effects of air pollution to the health, it is up to the health organizations to alleviate this problem.




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