LETTERS Air monitoring networks Dear Sir: I have just finished the excellent article on Air Monitoring Networks (€S&T, June 1977, pp 544-549). Unfortunately, the article leaves the reader with the impression that there are only three domestic and one international firms seriously engaged in the construction of network systems. I wish to point out that Monitor Labs has built eighteen (18) telemetry network systems. Installations include: California Air Resources Board statewide network. Department of Public Health, Commonwealth of Massachusetts. Georgia Power Company, Atlanta, Georgia. State of Victoria, Melbourne, Victoria, Australia. Department of Environment, State of Washington. Department of Environmental Quality, State of Wisconsin. Each of these networks consists of more than ten (10) remote sites with air quality and meteorological sensors telemetered to a central site with a computer
Bendix." has been added. We are very puzzled about this because these instruments were in fact supplied by Philips. A. S. Lodder N.V. Philips Gloeilampenfabrieken Eindhoven, The Netherlands
to control telemetry, validate the data, and perform data reduction. With our System 7000 measurement system and System 5000 ADAM network software, we offer a complete package with most of the equipment of our own manufacture. The major distinction between Monitor Labs and others in the field is that we specialize in hardware and computer software, leaving the data interpretation to the consultants. Allan L. Budd Vice President, Marketing Monitor Labs, Inc. San Diego, Calif. 92121
More on air monitoring networks Dear Sir: I was delighted to see your June issue with the article on building air monitoring networks. I noticed in the article errors that are rather important from our point of view. At the top of page 548 column 3, the figure for the total number of people employed in Philips should be of course 400 000. In the same column, paragraph 4, the sentence "The NO, NOn, and O3instruments were purchased from
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Environmental Science & Technology
Also In the air monitoring business Dear Sir: We would like to call readership attention to another company in the business of designing, constructing, installing and operating air monitoring networks (see €S&T Special Report, Building Air Monitoring Networks, June 1977, p 544). The EnvironmentalSystems Division of Xonics, Inc., based in Van Nuys, California, recently secured the EPA contract for data management and collection, and operation of the entire CHAMP network, having a cumulative value of approximately $5 million. Prior to this award, Xonics designed and delivered the air quality instrumentation systems under subcontract to Rockwell for use in the EPA-funded CHAMP and RAMS programs. Xonics' portion of the total contracts amounted to approximately $2.5 million. Xonics also is delivering air and water-quality monitoring systems under contract with the US. Army. Value of these orders exceeds $4 million. And, on the international scene, Xonics has delivered about $400 000 worth of monitoring equipment overseas, and has recently booked an additional $500 000. Xonics' engineering innovations led to many system hardware improvements, now consideredstandard practice in the industry, such as automatic dynamic gas calibration, accurate data conditioning, logging, integration, and display of air quality parameters, centralized ambient air-processing equipment, accurate temperature control of sensitive calibration components, meteorological monitoring equipment, and many others. Daniel L. Esau Director of Marketing
Air monitoring networks (cont.) Dear Sir: I was disappointedto see that the special report on air pollution monitoring (€S&T, June 1977, p 544) gave the impression that there are only three major companies providing total contractor services in the building and operation of air pollution monitoring networks (p 545, COI. 3). The facts are that several other companies are major factors in this field. Enviroplan, for example, has designed, installed, and has been operating air pollution and meteorological monitoring networks at more than forty site locations for several of our more than forty-five government and industrial clients. It is precisely because there now are a substantial and growing number of experienced and qualified companies providing these monitoring services that the electric
