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NGN-3a Nephelometer


Rear view of NGN-3a showing sample air inlet (spiral sampler not showing) and
external temperature sensor connector

The Model NGN-3a is an advanced design integrating polar Nephelometer used for the purpose of accurately measuring the scattering coefficient of dry air. The instrument uses a spiral sampler inlet to separate out particles larger than 2.5 microns to satisfy the PM2.5 standard. In addition, a heated measuring chamber dries the air sample to a preset relative humidity value. A relative humidity sensor is mounted in the sample air chamber. By measuring the scattered light over a 170 degree angle, the scattering extinction coefficient, Bscat, is reduced to units of inverse mega meters. Bmass is computed by applying a conversion factor. Bscat and/or Bmass is made available for output to analog and digital data loggers, PC computers or can be read directly from the integrated LCD display. Time, date, barometric pressure, temperature both inside and outside, RH and other important instrument settings are made available on the serial output for data capture. A unique 4-button keypad allows complete control of the NGN-3a. The keypad allows the initiation of clean air and span calibrations to be made easily. Various conversion constants and operating conditions can also be programmed with the keypad. The NGN-3a is entirely self-contained and, except for an external span gas supply, only a low voltage power source is required for operation.

Front panel view of NGN-3a showing clean air filter canister, span gas inlet, lamp assembly, 9-pin I/O connector, 4-button keypad and LCD display

Features Include: