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DataRAM 2000 Particulate Monitor Forest Service User's Guide
The DataRAM 2000 particulate monitor is a compact, self-con-tained instrument that internally estimates the mass concentration of particulate in the air from the measured scattering of light. The instrument can measure particulate concentrations from 0.1 to 400,000 micrograms per cubic meter of air. The instrument continuously displays the current and time-weighted average (TWA) mass concentration while logging up to 10,000 data points. Data can be transferred from the instrument to a laptop computer through the laptop's RS-232 serial port.
The DataRAM can be configured with either a PM2.5 or PM10 inlet head to prevent particles larger than 2.5 or 10 micrometers, respectively, from entering the optical chamber where particu-late is measured. The DR-PM10/2.5 model of the DataRAM 2000 is shipped for PM10 operation. To convert the inlet to PM2.5 operation, a conversion nozzle is threaded onto the central flow tube. The PM2.5 micrometer inlet is recommended for monitoring smoke (figure 1).
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| Figure 1-Inline impactor head with the PM2.5 nozzle installed. |
The impactor surface consists of a 25-millimeter-diameter glass fiber filter supported by one section of a standard plastic filter holder. Replace the glass filter when it has any brown or black soiled spots. Refer to the instruction note provided with the model DR-PM10/2.5 inline impactor head. A 37-millimeter filter located in the instrument's base can collect particulates for custom calibrations, or for analyzing the chemical composition of particulates. An inline heater should be installed for conditions above 70 percent relative humidity. The inline heater requires 120-volt line power. Humidity of 70 percent and above may occur at any time in the early morning, even during low-humidity days. The tubular heater is designed to evaporate liquid water from airborne particles or to eliminate fog droplets. The Data-RAM is powered by an internal rechargeable battery or by an external dc or ac power source. The Missoula Technology and Development Center (MTDC) recommends having 120-volt line power available for the DataRAM and inline heater.
The DataRAM is not approved by the U. S. Environmental Protection Agency (EPA) as a reference method sampler. The DataRAM instrument provides general trends of smoke partic-ulate concentration. These data can enable the user to verify whether the impacts of smoke particulate are increasing or decreasing. A correction factor of 0.48 is applied to the DataRAM based on experimental data. In other words, if the DataRAM shows 100 micrograms of particulate per cubic meter of air, an EPA-approved reference method sampler would be expected to show about 48 micrograms of particulate per cubic meter of air.
The center published Real-Time Smoke Particulate Sampling: Fire Storm 2000 (0125-2832-MTDC) which explains EPA air-quality standards and how the DataRAM 2000 correction factor of 0.48 was determined.
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