SURVEY OF EYE IRRITATION AND LACHRYMATION IN RELATION TO AIR POLLUTION - FINAL REPORT
|Publication Date:||15 April 1974|
It is widely recognized that feelings of eye irritation are the most frequently reported symptoms associated with the exposure of humans to air pollution. Many studies of this phenomenon have been conducted, particularly over the past 25 years. However, most of these studies have been conducted along disciplinary lines, without viewing the problem in an overall context.
To date, most work has been aimed at the identification of chemical species that cause eye irritation. Yet, as can be seen in the following statement published only a few years ago by the National Air Pollution Control Administration, even this fundamental question remained largely unanswered:
Based on the existing data, it appears that: (1) the effective eye irritants are the products of photochemical reactions; (2) although oxidant concentrations may correlate with the severity of eye irrirtation, a direct cause-effect relationship has not been demonstrated since ozone, the principal contributor to ambient oxidant levels, is not an eye irritant; (3) the precursors of the eye irritants are organic compounds in combination with oxides of nitrogen, the most potent being aromatic hydrocarbons; (4) the chemical identities of the effective irritants in synthetic systems are known as being formaldehyde, peroxybenzoyl nitrate (PBzN), peroxyacetyl nitrate (PAN), and acrolein, although the latter two contribute to only a minor extent; and (5) the substances causing eye irritation in the atmosphere have not been completely defined.
Some inquiries also have been made into psychophysical aspects of eye irritation with various levels of success. Specifically, such questions have been addressed as are listed below:
• What is the mechanism that produces discomfort to the eyes in the presence of air pollution?
• What methods of measurement, including both questionnaires and physiologic indices, are available for measuring eye irritation and/or lachrymation?
• What are the dose response relationships between atmospheric concentrations of suspected eye irritants and the kind and degree of discomfort produced?
• Is there a simple indicator which can be used to estimate the eye irritation potential of the atmosphere?
From a societal point of view, these questions must be resolved so that the magnitude of the problem can be understood and appropriate solutions can be effected. The extenet to which they have been answered is the subject of this report.