Advantages of the System The system is so constructed that expansion to twenty plus stations may be accomplished by installing additional circuit modules and adding chassis by merely tying into existing connectors. Each remote station will be able to accept inputs from as many as five different air quality analyzers. Encoders allow the user to utilize any of the available analyzer instruments by tying onto the shaft of the recorder which in most cases is an integral part of the analyzer. It also presents linearized and scaled output and no data interpretation is required. They add no errors to the analyzer accuracy. Digital transmission precludes any degradation of system accuracy. Using teletype recording equipment allows the use of lowest cost telephone lines. Minimal modification is required for tying the system to an on-line computer for complete pollution monitoring. CONCLUSION The Telemetered Air Monitoring Network information will be used to: 1. Advise the public of the air quality in the City of Chicago. 2. Provide the back-up information with which health studies will be correlated. 3. Provide the information to determine the effectiveness of the enforcement program in reducing sulphur dioxide. 4. Provide an enforcement tool to pinpoint large emittors of sulphur dioxide. 5. Provide the information to support the design and operation of a diffusion model for the City of Chicago. 6. Establish air quality standards as an aid to enforcement. 7. Develop an air pollution climatology for the City of Chicago. station. Data gathered at each remote site include sulphur dioxide in parts per million, a five-minute integrated wind direction to the nearest degree and a five-minute integrated wind speed to the nearest one-tenth knot. (Figure 5) (Figure 6) Fifteen-minute intervals were selected because of their representativeness over a 24-hour period, thereby precluding the likelihood of excessive highs and lows occurring without being detected. A new and rather unique meteorological method is employed in the recording of 15-minute intervals inasmuch as wind speed and direction are "integrated," i.e., readings on wind speed and direction are taken every five seconds and are stored in the electronic memory; the information is then averaged by the computer for 15-minute readings and recorded. The problem of eliminating ambiguity of readings of wind speed and direction was solved by suing two Selson motors counter-clockwise. At pre-slected intervals the central station clock signals the beginning of a recording cycle. The programmer starts the printer and tape punch and initiates the recording of the date-time group and parameter data which is utilized by the computer for the analysis assigned to the block of data. The programmer then interrogates the first station, and it immediately transmits its three-digit identification followed by the air quality and wind data. This is repeated for all stations with a total transmission time of 40 seconds. The central station control panel allows for automatic or manual selection of signals for zero checks, calibration checks, and changes of sampling and recording intervals. Further, it contains provisions for by-passing a station in the event of line or equipment difficulties, initiation of demand recording cycles and indicators to show functions taking place. The central console incorporates a graphic display representing the metropolitan Chicago area with indicators that illuminate each station location when the station is transmitting data. Advantages of the System The system is so constructed that expansion to twenty plus stations may be accomplished by installing additional circuit modules and adding chassis by merely tying into existing connectors. Each remote station will be able to accept inputs from as many as five different air quality analyzers. Encoders allow the user to utilize any of the available analyzer instruments by tying onto the shaft of the recorder which in most cases is an integral part of the analyzer. It also presents linearized and scaled output and no data interpretation is required. They add no errors to the analyzer accuracy. Digital transmission precludes any degradation of system accuracy. Using teletype recording equipment allows the use of lowest cost telephone lines. Minimal modification is required for tying the system to an on-line computer for complete pollution monitoring. CONCLUSION The Telemetered Air Monitoring Network information will be used to: 1. Advise the public of the air quality in the City of Chicago. 2. Provide the back-up information with which health studies will be correlated. 3. Provide the information to determine the effectiveness of the enforcement program in reducing sulphur dioxide. 4. Provide an enforcement tool to pinpoint large emittors of sulphur dioxide. 5. Provide the information to support the design and operation of a diffusion model for the City of Chicago. 6. Establish air quality standards as an aid to enforcement. 7. Develop an air pollution climatology for the City of Chicago. |