2-WIN (Two Wavelength Integrating Nephelometer)

The Ambilabs® dual wavelength nephelometer is a robust ambient air-quality instrument designed to provide measurements of particle concentrations, ambient visibility, and source apportionment information. The unit includes an LCD display to provide information about measured parameters, flow rate, instrument status and power. An active heating system which is controlled based on relative humidity levels warms the sample air and sample cell to keep the RH below a set point to avoid particle growth with humidity. Additional features include a purge air system and an automatic zero calibration routine. The instrument can be installed in any ambient shelter or monitoring facility.

The Ambilabs® dual wavelength nephelometer determines particulate concentration by measuring the total scatter from aerosols and using a selectable wavelength, while both wavelengths are used to determine the scattering Ångström exponent which is inversely related to particle size in the sample air, showing basically the average (mode) diameter of the measured particle size distribution. While the time series of the scattering coefficient already represents the measured particle concentration, the Ambilabs® dual wavelength nephelometer has a separate output for a PMestimate based on a user selectable calibration with measurement range of 0 to 100 mg/cubic meter or 0 to 100,000 ug/cubic meter. Optional sharp-cut cyclones can be used to select the sample flow for PM2.5 size fractions.

The 2-WIN includes patented light source technology; US Patent #7,671,988 B2.


  • Easy automatic calibration with cost effective (low grade) CO2 gas ensures repeatability of measurement
  • Automatic optical reference calibration
  • High powered LED light source increases measurement accuracy
  • Single light source and detector used for all wavelengths
  • Facilitates a wide measuring range (0 to 20,000Mm⁻¹)
  • Compact and portable
  • QA parameters available like “cleaning indicator” (wall count) and “lamp intensity drift” (shutter count)
  • Internal sample heater with temperature or RH control, which can be enabled by the user to eliminate effects of humidity RH: <30% to <90%
  • Fully automatic zero check or adjust, automatic span check or automatic zero and span check available in intervals of 1, 3, 6, 12, 24 hours or weekly
  • Fully integrated package including: internal sample pump, sample heater, internal calibration valves,zero air pump, and data logger
  • Low power internal 12V sample heater
  • Long lasting LED light source
  • Very low cost of ownership


  • Measurements of light scattering
  • Air Quality Index / PMestimate
  • Source apportionment
  • Ångström exponent calculations
  • Smoke monitoring
  • Ambient dust monitoring
  • Industrial process measurements
  • Clean rooms
  • Climate Change
  • Other research applications