New Yorks Acid Deposition Monitoring Network
New York monitors and tests for acid deposition through the New York State Atmospheric Deposition Monitoring Network, which was designed in 1985 to carry out requirements of the State Acid Deposition Control Act (SADCA). Measurements of acid deposition and related quantities are used to assess the effectiveness of sulfur control policy and other strategies aimed at reducing the effects of acid rain.
The network's objectives are:
- Provide a consistent, quality-assured, long-term acid deposition database.
- Measure acid deposition in sensitive receptor areas.
- Measure acid deposition in urban and upwind areas.
- Use these data to perform spatial and temporal analyses of acid deposition, its precursors, and its effects.
- Track the effectiveness of programs to reduce acid deposition precursor emissions.
How the Monitoring Network Works
The monitoring network consists of about 20 sites located throughout the state, in both rural and urban areas. Rainfall measurements are automatically recorded, but for other parameters, samples are collected manually from each site and then transported to our laboratory for analysis. Instrumentation is unavailable to automate the deposition sampling and analysis of pH, conductivity, cation concentrations and anion concentrations.
The DEC is presently monitoring acid deposition. Sample collection began in June, 1986, with 12 sites, but these data are not considered valid due to shakedown. The official start-up for the network is January 1, 1987. Sites were added in 1987, 1988, 1989, 1990, 1991, 1994, 2001, and 2004. The DEC will try to continue to expand the network until the design target of 25 sites is reached. The schedule depends upon budget provisions.
Site Classifications
The network is composed of three classes of monitoring sites which differ by the amount and kind of instrumentation used. They are designated "Type 3," "Type 2," and "Type 1."
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Type 3 Sites have two types of instrumentation. The first is a tipping bucket rain/snow gauge to measure the amount of precipitation. The output signal is connected to either a recorder or a telemetry unit. The second device is a Viking Hyetometer which is a bucket type collector designed to collect samples under wet or dry conditions. Wet deposition samples are gathered in the lined buckets when precipitation is occurring. Because no adequate methodology has been established for analysis of dry side samples, only the wet side samples are analyzed.
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Type 2 Sites have all the devices operated at a Type 3 site and they also incorporate continuous monitoring instrumentation to measure the ambient concentration of selected components. These instruments are connected via telemetry to a central computer. Beginning in 1991, several low-level SO2 and ozone analyzers have been installed and are in operation. Type 2 Sites are also designed to measure relative humidity, temperature, and atmospheric pressure. Additional analyzers may be added, given adequate resources.
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Type 1 Sites, in addition to having the instrumentation used at Type 2 Sites, also measure wind speed and direction, and calculate horizontal sigma (wind direction variability).
Sampling Equipment
Viking Hyetometer Precipitation Collector
The Viking Environmental Instruments, Inc. hyetometer is an automatic sensing wet/dry precipitation collector. A sensor detects precipitation events and triggers the stainless steel direct drive acme screw activator which removes the cover from the wet-side collector bucket and moves it to the dry-side bucket. When the precipitation event ends, the cover returns to the wet-side bucket. The sensor consists of two parallel plates. When water droplets bridge the gap between these plates, the sensor circuit is closed and the cover movement is begun.
Tipping Bucket Rain/Snow Gauge
The Sierra Misco Model 2500E is a tipping bucket rain/snow gauge with an electronic heating system that melts frozen precipitation and maintains it in a liquid state until it has exited from the device. One tip is equivalent to 0.01 inch of rain. The rain gauge is connected to either a chart recorder or a telemetry unit to record the amount of precipitation measured.
Belfort Rain Gauge
In 1999 the Belfort Rain Gauge Model 3200 began to be installed at the monitoring sites. Presently 16 sites have the Belfort gauge installed and all the sites should have them by the end of the year 2001. The major advantages of the Belfort gauge over the Sierra Misco Model 2500E are that it does not have to be emptied as often, and it is able to measure heavy downpours more accurately.
Contact us
If you have questions or need additional information about the acid deposition monitoring program, please contact us by e-mail.
More about New Yorks Acid Deposition Monitoring Network:
- Acid Deposition Monitoring Sites - The following table provides a listing of the current monitoring sites which are collecting acid deposition samples and rainfall data
- Acid Deposition Monitoring Sites Details - The following links provides a listing of the current monitoring sites which are collecting acid deposition samples and rainfall data.
