Ecology: Menace in the Skies

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Damage to People. Pollutants that injure plants and erode stone are likely to have a damaging effect on humans too. Motorists who would never contemplate committing suicide by running a hose from their exhaust pipe into the car often unknowingly endanger their lives by exposing themselves to large amounts of carbon monoxide on expressways and in tunnels and garages. Though an hour's exposure to 1,500 parts of monoxide per million parts of air can endanger a man's life, only 120 parts per million for an hour can affect his driving enough to cause an accident. And concentrations of about 100 parts per million have been found in tunnels and garages and on the streets of Chicago, Detroit, New York and London.

Assistant Surgeon General Prindle points out that a heavy cigarette smoker carries a 3% to 4% concentration of carbon monoxide in his bloodstream. Thus it is not surprising, he says, that habitual smokers are the first to turn up at hospitals during periods of extreme air pollution; carbon monoxide concentrations in their bloodstream reach a toxic 25%-30% level before those of nonsmokers.

Chief culprits in the Donora, London and New York smog disasters were probably sulphur dioxide and sulphur trioxide, which, either in gaseous form or converted into sulphuric-acid mist, can irritate the skin, eyes and upper respiratory tract. Extreme exposure, such as might occur in an industrial accident, can do irreparable damage to the lungs—and even attack the enamel on teeth.

Arsenic & Heart Disease. Ozone and PAN produce the eye irritation, coughing and chest soreness experienced by many Los Angeles residents on smoggy days. In laboratory experiments, continuous exposure to ozone shortened the lives of guinea pigs. Scientists have also calculated that a child born in New York City after World War II has now inhaled the pollution equivalent of smoking nine cigarettes per day every day of his life. Like those in cigarettes, some of the hydrocarbons identified in automobile exhausts have produced cancer in laboratory animals.

The particles in pollution are injurious to humans also. Carbon particles that blacken the lungs of residents of London and New York carry gases adsorbed onto their surface. They enable suhphur dioxide, for example, to penetrate deeper into the lungs than it could on its own; without particles to carry it, the gas can be exhaled relatively easily from the upper respiratory tract. Other participates act as catalysts in the atmosphere, speeding the conversion of sulphur dioxide into more harmful sulphuric acid. Particles of arsenic, beryllium, cadmium, lead, chromium and possibly manganese, discharged into the atmosphere by a variety of man-made processes, may contribute to cancer and heart disease.

Though researchers have not been able to prove a direct cause-and-effect relationship between air pollution and disease, they have found that the incidence of chronic bronchitis among British mailmen who deliver mail in areas with heavy air pollution is three times as high as among mailmen who work in cleaner regions. Researchers also know that there are more deaths from chronic pulmonary disease in high-pollution areas of Buffalo than in other neighborhoods. Boston policemen working around high concentrations of carbon monoxide seem more susceptible to the common cold.