Air Pollution and Asthma

The rapid growth of population and industry during the last 25 years has resulted in a marked increase of emissions into the atmosphere of a complex mixture of gaseous and solid materials which react not only with each other but with the atmosphere itself. These substances in the atmosphere breathed by man have become a subject of increasing concern to health authorities. The effects of air contaminants on health are difficult to assess. The concentration of air pollutants varies both chronologically and spatially, depending upon climate and atmospheric conditions. Individuals are exposed to varying levels of various pollutants during the course of a single day. It would appear reasonable to suppose that among those who might be most susceptible to the aspiration of pollutants would be those individuals who suffer from asthma. Until recently, allergists have been concerned with the most frequently recognized causes of allergic asthma, namely airborne molds, spores, pollens and dusts. More recently, in addition to these, the allergists are now giving consideration to industrial and urban air contaminants such as sulfur dioxide, carbon monoxide, hydrocarbons, oxides of nitrogen, ozone, many kinds of particulate matter, and other air pollutants. The sources from which these pollutants emanate are many and varied. A few of the more common ones are automobile traffic fumes, chemicals, vapors of dry-cleaning fluids, naphthalene flakes, paints, and gases from leaky heating, cooking and refrigerating equipment.l That there has been an increase in the variety of such substances discharged into the atmosphere is unquestioned. According to Criep, this increase in air pollution has been contributing indirectly to the severity of bronchial asthma and its complications.2 The effects of air pollution on asthmatics is especially evident in industry. Most cases of asthma found in industry have been attributed directly to inorganic and organic mineral dusts, fumes, and ~apors.~ Much of the information concerning the effects of air pollution upon allergy and asthma has been based on observations made in private clinical practice. More recently, epidemiological studies have been conducted in an effort to relate air pollution, and in some cases specific air-borne agents, to the causation of asthma.