ATLAS GAS ANA LYZ ERS
D.
Bartlett Jr.,
Arch. Environ. Hlth.,
16,719 (1968). J.
R. Goldsmith a n d S. A. Landaw,
Science, 162, 1352 (1968).
These papers should provide a more up-to-date familiarity with the subject of low level toxicity of carbon monoxide. I have no idea where Silver’s “review” can be found and he is apparently not sure either. M. Y. Longley Institute of Gas Technology IIT Center Chicago, Ill. 60616
THE NEW INDUSTRY STANDARD FOR AIR POLLUTION MONITORING
Correction: The srandaid f o r CO industrial exposure has been lowered fro111100 p.p.m. to 50 p.p.ni., and not 5 p.p.tn. as printed in SI/tei’5 ierrer-Ed.
so2
Specific Colorimetric
and Reducing Agents lodometric
NO2
03
Specific Colorimetric
and Total Oxidants lodometric
NO Specific Colorimetric
Aldehydes Specific Colorimetric
NOX Specific Colorimetric
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Circle No. 4 on Readers’ Service Card
1224 Environmental Science & Technolog?
Trichloroethylene a n d smog
DEARSIR: We would like to comment on the Stanford Research Institute (SRI) study on the smog forming capabilities of trichloroethylene-highlighted on page 869 of your October issue. I Considering the differences in experimental procedures used by SRI as compared to those of the Los Angeles County Air Pollution Control District-differences in light intensities, hydrocarbon:NO, ratios, residence times, and the use of dynamic conditions for some experiments-which make direct comparison of the data somewhat difficult, we feel that the SRI data confirm out findings regarding the relative activity of the hydrocarbons tested, We do not agree with many of the conclusions that SRI has drawn from , the data presented to us; for example, that “any contribution of trichloroethylene to photochemical smog manifestations would be negligible,” or that comparison shows “that nearly identical effects resulted from the addition of n-paraffins and trichloroethylene.” Our evaluation of the SRI data leads us to the conclusion that, photochemically, trichloroethylene more closely resembles olefins or xylenes than it does n-paraffins. Our conclusion of the data in the report is that they essentially confirm the findings of the Los Angeles County Air Pollution Control District that trichloroethylene is a photochemically reactive solvent-a solvent that Rule 66 was designed to control. ~
Robert L. Chaw Los Angeles County Air Pollution Control District Los Angeles, Calif. 90013
