current research
Role of SO, and Photochemical Aerosol in Eye Irritation fromPhotochemica1 Smog William E. Wilson, Jr.1 and Arthur Levy Battelle Memorial Institute, Columbus Laboratories, 505 King Avenue, Columbus, OH 43201
E. Harvey McDonald Continental Oil Co., Ponca City, OK 74601
Experimental Measurements were made with irradiated auto exhaust and pure organic compounds to determine the influence of SOz and photochemical aerosol on eye irritation. Auto exhaust and mixtures of nitrogen oxides and a variety of organic compounds were irradiated in a 610-ft3smog chamber. Responsedelay and intensity measurements of eye irritation were made by seven-member panels. Exposure was through ports in the irradiation chamber. The addition of SO2, although it increased aerosol formation, produced a decrease in eye irritation with many of the hydrocarbon/NO, systems studied. Sulfuric acid aerosol, produced by the photooxidation of SOz in clean air, does not cause eye irritation. However, photochemical aerosol, generated from 1-heptene and nitrogen oxides in the absence of SOn, does cause eye irritation. This was demonstrated in one run in which the photochemical aerosol was removed by rapid stirring. It is concluded that the effect of SOZis not related to changes in aerosol formation but is due to a chemical interaction which modifies the gas-phase products.
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umerous studies have investigated the influence of SOs on aerosol formation (Wilson et al., 1969; Wilson, 1971). A lesser effort has been devoted to other aspects of the interaction between SO, and photochemical smog although the effect of SO2 on reaction rates and on NOz and oxidant concentrations has been examined (Wilson and Levy, 1968-70; Wilson et al., 1972). This study was undertaken to determine if there was a relationship between eye irritation and SO2 concentration. In this study, eye irritation measurements were made during several experiments with Battelle’s 610-ft3smog chamber to determine the role of SO2 and photochemical aerosol in eye irritation.
Present address: Atmospheric Aerosol Research Section, Environmental Protection Agency, Research Triangle Park, NC 2771 1. To whom correspondence should be addressed.
Eye irritation was measured by the response-delay and the intensity methods according to standard Battelle procedures (Levy and Miller, 1970)similar to that used by the Los Angeles County Air Pollution Control District (Brunelle et al., 1966). After 6 hr of irradiation, panels of seven subjects were exposed to the contents of the smog chamber through eye ports in the chamber wall. The panelists, volunteers from the Battelle staff, were screened to eliminate hypersensitive and insensitive subjects. The primary measurement of eye irritation (response-delay) was made by determining the time to irritation-Le., the duration of exposure prior to onset of irritation. This measurement is reported in the tables as “equiv sec” (antilog of the average of the logs of the individual response-delay times). The maximum exposure time was 360 sec. The subjects also reported their response in terms of the severity of the eye irritation. The irritation was judged to be “severe,” “moderate,” “slight,” or “equivalent to clean air.” The techniques used to measure eye irritation and the validity of the data has been reviewed by Wayne (1967) and discussed in more recent articles (Heuss and Glasson, 1968; Altshuller et al., 1969; Levy and Miller, 1970). A statistical analysis was made of the 100 runs performed at Battelle Columbus for the National Paint, Varnish, and Lacquer Association (Levy and Miller, 1970). Results of this analysis, as yet unpublished, indicated a correlation of 0.96 between reaction time and subjective severity and supported the division of eye irritation into the four categories of severity. The analysis further indicated that an individual panelist’s response to the same chemical system, measured over a period of two years, was constant to =t25 %. For this study the comparisons were made with identical panelists within a time frame of a few days. In each case the presence or absence of SOz or organic aerosol resulted in a change in severity class. The differences in eye irritation reported may therefore be considered highly significant without recourse to statistical interpretation. SOzwas measured by a coulometric technique using a Beckman 906 analyzer whose calibration was checked with permeation tubes. Oxidant was measured with a Mast ozone meter whose response to ozone was calibrated with neutral KI solution (Mast and Saunders, 1962). A dichromate scrubVolume 6, Number 5, May 1972 423
Table I. Effect of SO2on Eye Irritation Solvent, 4 ppm; NO, 2 ppm
Hydrocarbon Concnc 9 9 21 21 21 21 23.8 23.8 23.8 23.8 12 12 8 8 8 8 8
Type Propylene I-Heptene
Olefin-aromatic mixturei
Exhaust from Fuel AI Exhaust from Fuel Aj Exhaust from Fuel Bk NOz
=
NO
+ NOz.
NOZa,concnc
SO2,concnc
1.5 1.5 1.5 1.5 1.5 1.5
1
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Wilson, W. E., Jr., Division of Colloid and Surface Chemistry, 161st Meeting, ACS, Los Angeles, Calif., March 1971. Wilson, W. E., Jr., Levy, A., “A Study of Sulfur Dioxide in Photochemical Smog I,” Battelle Memorial Institute Report to the American Petroleum Institute, Committee for Air and Water Conservation, August 1968. Wilson, W. E., Jr., Levy, A., “A Study of Sulfur Dioxide in Photochemical Smog 11,” Battelle Memorial Institute Report to the American Petroleum Institute, Committee for Air and Water Conservation, August 1969. Wilson, W. E., Jr., Levy, A,, J . Air Pollut. Contr. Ass., 20, 385-90 (1970). Wilson, W. E., Jr., Merryman, E. L., Levy, A., “ALiterature Survey of Aerosol Formation and Visibility Reduction in Photochemical Smog,” Battelle Memorial Institute Report
to the American Petroleum Institute, Committee for Air and Water Conservation, August 1969. Wilson, W. E., Jr., Levy, A., Wimmer, D. B., J . Air Pollut. Contr. Ass., 22 (1972). Wilson, W. E., Jr., Merryman, E. L., Levy, A., Taliaferro, H. R., J . AirPollut. Contr. Ass., 21, 128-32 (1971). Received for reciew January 22, 1971. Accepted December 27, 1971. This paper was supported by the Department of Health, Education and Welfare through Grant AP 00828 from the National Air Pollution Control Administration, Emironmental Health Service, Public Health Sercice. The eye irritation measurements were supported by Battelle in-house research ,funds and were obtained incidental to smog chamber studies supported in part by the American Petroleum Institute and in part by Battelle
Ozone-Induced Changes in Corn Pollen Richard A. Mumford,’ Herbert Lipke,* and Daniel A. Laufer Departments of Biology and Chemistry, University of Massachusetts, Boston, MA 021 16
William A. Feder Department of Environmental Sciences, University of Massachusetts, Waltham, MA 02154
Free amino acids of corn pollen increased 50% following exposure t o ozone at 3 pphm. Higher levels further enhanced amino acid and peptide accumulation and inhibited germination 40-90x. Total a-amino N, free amino acids, and ethanolsoluble peptides increased in proportion to ozone exposure. Amino acid accumulation was greatest for a-alanine, glutamic acid, and proline. Reducing and neutral sugars bound to ethanol-soluble peptides decreased. No change in the titer or composition of the sulfur-containing F3 histone was observed. The data suggest that ozone induces the autolysis of structural glycoproteins and stimulates amino acid synthesis.
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n Boston and Los Angeles, peak summer concentrations of ozone (Os) reach levels of 20 and 100 parts per hundred million (pphm), respectively (Cooke et al., 1969; Feder, 1970). Plants exposed to comparable levels of O3 show both structural abnormalities (Thomas, 1951; Rich, 1964; Darley and Middleton, 1966) and an accumulation of amino acids and carbohydrates in the leaf (Dugger and Ting, 1970). In addition, germination of corn, petunia, and tobacco pollen is reduced, the decline is manifest both in intact plants and in isolated pollen ozonated after removal from untreated plants (Feder, 1970). In the higher plants, fertilization is accomplished by transfer of the germinative nucleus from the pollen grain t o the ovule, the transfer is effected by growth of the pollen tube from the germinated grain to the ovule via the stigma and style. Since normal growth of the pollen tube is required for
Present address, Department of Biochemistry, Eunice Kennedy Shriver Research Center, Waltham, MA 02154. To whom correspondence should be addressed.
fertilization, inhibition of tube development adversely affects the reproductive potential of the plant. Feder (1970) observed a reduction in the rate and magnitude of tube elongation following ozonization, at low levels of exposure the inhibition could be reversed by a return to normal environment. Since germination requires the production of protein-polysaccharide complexes from nitrogenous stores and polysaccharide depots (Stanley, 1971; Van der Woude et al., 1971), levels of amino acids and peptides have been determined in ozone-treated pollen to establish if these metabolites could serve as sensitive indices of damage from atmospheric pollutants. The reversible inhibition of growth observed by Feder (1970) following the removal of pollen from an ozone atmosphere, suggested that a regulator of pollen tube formation was rendered temporarily nonfunctional by oxidation of an ozonesensitive site. In this respect, the basic protein of the cell nucleus, the histones, are presumed to regulate the expression of the genetic potential of the cell by interaction with specific regions of DNA (Farmbrough et al., 1968). One of these basic proteins, the F3 histone, includes an oxidizable thiol group (Ord and Stocken, 1968). Since thiols are readily oxidized by ozone, the distribution and composition of pollen histones has been monitored during the course of ozonation in vivo. Experimental
Corn (Zea Maize, var. Harvard Hybrid-dwarf) was grown in greenhouses during winter months when ozone was not detectable. Plants were grown on a steam-sterilized sandy loam, fertilized with a 15-15-15 commercial mix. The day length was maintained at 12 hr with fluorescent lighting. Growth was normal for this variety when maintained at a day temperature of 85-90°F and a night temperature of 72’F. Weekly inspections revealed no damage from pathogens or insects. The ozonated corn was grown in greenhouses in which the ozone level was maintained at 3, 6, and 12 pphm of O3for 5 . 5 hr/day for 60 days with a Welsback Ozonator Model RB-2. The Volume 6, Number 5 , May 1972 427
