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Meteorological parameters and concentration of total suspended particulates in the urban area of Rio de Janeiro
634
Discussrons
FURTHER
DISCUSSION
I appreciate Dr. Lindberg’s reply to my letter. The ethciency of iodized charcoal for mercury has been known for some time as pointed by Dr. Lindberg. I have never had any doubts about many earlier laboratory evaluation studies on this subject matter. As Dr. Lindberg points out in his reply, the inetTiciency of mercury collection in stack sampling by laboratory evaluated media, has been known for some time. This fact alone should have suggested that mercury efficiencies of commonly used media, including iodized charcoal. be evaluated in the stack and plume atmospheres. I agree with Dr. Lindberg’s contention that in stack studies are not the best surrogates for all our m-plume measurements; however, 1 think in view of the reported losses during stack sampling one should at least be
SMOKE AS A QUANTITATIVE ATMOSPHERIC DIFFUSION TRACER*
curious, investigate, and not take for granted m-plume mercury efficiencies. After all most scientific discoveries orginate through curiosity. My comment on mercury speciation essentially is speculative and is based on the reports that iodized charcoal collects elemental mercury and other organic mercury compounds efficiently. Determination of mercury speciation in Dr. Lindberg’s samples would have been interesting in view of recent reports identifying organic mercury compounds in flue gases. Research Triangle tnstitute ARUN D. SHENDR~KAR Energy and Environmental Technolog) P.O. Box 12194, Research Triangle Par!, NC 27709. LT.S.A.
gas or particle samplers. Two automatic cameras properly
Gifford’s analysis of plume photographs to derive y and z is fully supported by our field experience with the wealth of information that can be obtained from pictures. I would like to see more work done on visible tracer studies in rough terrain where traditional Gaussian models are least accurate. The use of a few well-placed cameras to document the dispersion of an oil fog or other visible tracer may be far more cost effective than the use of many point-measurement
oriented to the side of a visible tracer plume can provide three dimensional information on the plume position as a function of time. Combining such “stereo” photography with wind sensors can provide even more input to the development of realistic dispersion models. The photographic slides can be digitized on microdensitometers to provide optical densities for small square segments, 25 pm a side. This digital information can be processed by computer programs to extract more information than is possible with manual measurement of the plume dimensions.
“Gifford F. A. (I 980) Atmosphwic Enrmmmr~nt 14, I I I9 1121.
University of Nevada Las Vegas. ,v V 89154, U.S. 4.
Visibility Research Center
METEOROLOGICAL PARAMETERS AND CONCENTRATION OF TOTAL SUSPENDED PARTICULATES IN THE URBAN AREA OF RIO DE JANEIRO+ The paper by Trindade et al. extends our knowledge of urban air pollution problems to a new regime of meteorological influences. I am. of course, pleased to see that the methods developed in our laboratory are proving useful at other locations. Although the authors indtcate that the study was based on existing Hi Vol TSP data, they have not discussed the reasoning which led to the ban on incineration. It would be helpful to know what improvement in air quality was expected from this regulation. The conclusions (p. 975, col. 2, paragraph 1, and p. 977, col. 2, paragraph 1)about the effect of the elimination of incineration should be based on com-
Trindade H. A., Oliveira A. E., Pfeiffer W. C., Londres H. and Costa-Ribeiro C. Atmospheric Environment 14, 973 978. l
ERIC C. WAtTHER
parisons of the same perrod in each year representing in 1977 only the period after incineration ceased. From the graph in Fig. 3 of Tc for Copacabana it appears some effect occurred, while Fig. 2a obviously can’t be interpreted to show any improvement. It would be useful to have the data for TSPand corrected TSP (Tc) in Copacabana retested statistically for the period of April-September in 1976 and 1977 rather than the October-September periods in 1975-1976 and 19761977. If a significant difference is found between Tc for the two periods, the results could be compared to the expectations on which the regulatory action was based. The paper supports the efforts of Holzworth and Kleinman to understand &e effects of dispersion and to separate these effects from the effects due to the sources of the TSP. They have made useful suggestions as to further improvements in the methods regarding dispersion corrections and I hope they can continue to test the improved techniques they indicate may be useful.
Institute for Environmc~ntalStudies New York UnivrrsitJ Medical Center 550 First Avenue New York, NY 10016, U.S.A.
T. J. KNEIP
Discussrons
FURTHER
DISCUSSION
I appreciate Dr. Lindberg’s reply to my letter. The ethciency of iodized charcoal for mercury has been known for some time as pointed by Dr. Lindberg. I have never had any doubts about many earlier laboratory evaluation studies on this subject matter. As Dr. Lindberg points out in his reply, the inetTiciency of mercury collection in stack sampling by laboratory evaluated media, has been known for some time. This fact alone should have suggested that mercury efficiencies of commonly used media, including iodized charcoal. be evaluated in the stack and plume atmospheres. I agree with Dr. Lindberg’s contention that in stack studies are not the best surrogates for all our m-plume measurements; however, 1 think in view of the reported losses during stack sampling one should at least be
SMOKE AS A QUANTITATIVE ATMOSPHERIC DIFFUSION TRACER*
curious, investigate, and not take for granted m-plume mercury efficiencies. After all most scientific discoveries orginate through curiosity. My comment on mercury speciation essentially is speculative and is based on the reports that iodized charcoal collects elemental mercury and other organic mercury compounds efficiently. Determination of mercury speciation in Dr. Lindberg’s samples would have been interesting in view of recent reports identifying organic mercury compounds in flue gases. Research Triangle tnstitute ARUN D. SHENDR~KAR Energy and Environmental Technolog) P.O. Box 12194, Research Triangle Par!, NC 27709. LT.S.A.
gas or particle samplers. Two automatic cameras properly
Gifford’s analysis of plume photographs to derive y and z is fully supported by our field experience with the wealth of information that can be obtained from pictures. I would like to see more work done on visible tracer studies in rough terrain where traditional Gaussian models are least accurate. The use of a few well-placed cameras to document the dispersion of an oil fog or other visible tracer may be far more cost effective than the use of many point-measurement
oriented to the side of a visible tracer plume can provide three dimensional information on the plume position as a function of time. Combining such “stereo” photography with wind sensors can provide even more input to the development of realistic dispersion models. The photographic slides can be digitized on microdensitometers to provide optical densities for small square segments, 25 pm a side. This digital information can be processed by computer programs to extract more information than is possible with manual measurement of the plume dimensions.
“Gifford F. A. (I 980) Atmosphwic Enrmmmr~nt 14, I I I9 1121.
University of Nevada Las Vegas. ,v V 89154, U.S. 4.
Visibility Research Center
METEOROLOGICAL PARAMETERS AND CONCENTRATION OF TOTAL SUSPENDED PARTICULATES IN THE URBAN AREA OF RIO DE JANEIRO+ The paper by Trindade et al. extends our knowledge of urban air pollution problems to a new regime of meteorological influences. I am. of course, pleased to see that the methods developed in our laboratory are proving useful at other locations. Although the authors indtcate that the study was based on existing Hi Vol TSP data, they have not discussed the reasoning which led to the ban on incineration. It would be helpful to know what improvement in air quality was expected from this regulation. The conclusions (p. 975, col. 2, paragraph 1, and p. 977, col. 2, paragraph 1)about the effect of the elimination of incineration should be based on com-
Trindade H. A., Oliveira A. E., Pfeiffer W. C., Londres H. and Costa-Ribeiro C. Atmospheric Environment 14, 973 978. l
ERIC C. WAtTHER
parisons of the same perrod in each year representing in 1977 only the period after incineration ceased. From the graph in Fig. 3 of Tc for Copacabana it appears some effect occurred, while Fig. 2a obviously can’t be interpreted to show any improvement. It would be useful to have the data for TSPand corrected TSP (Tc) in Copacabana retested statistically for the period of April-September in 1976 and 1977 rather than the October-September periods in 1975-1976 and 19761977. If a significant difference is found between Tc for the two periods, the results could be compared to the expectations on which the regulatory action was based. The paper supports the efforts of Holzworth and Kleinman to understand &e effects of dispersion and to separate these effects from the effects due to the sources of the TSP. They have made useful suggestions as to further improvements in the methods regarding dispersion corrections and I hope they can continue to test the improved techniques they indicate may be useful.
Institute for Environmc~ntalStudies New York UnivrrsitJ Medical Center 550 First Avenue New York, NY 10016, U.S.A.
T. J. KNEIP