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.
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."
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.
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.
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).