Aurora 2000

PM2.5 Correlating Nephelometer

The Aurora 2000 PM2.5 Correlating Nephelometer is part of the ‘new generation’ nephelometers using a single wavelength and an BETA monitor to measure aerosol light scattering and derive particulate concentrations.

The Aurora 2000 enables the calculation of a correlation factor based on a PM2.5 reference method which is then used to derive every minute a PM2.5 concentrations along with the usual light scattering. The correction factor can be entered manually or automatically derived from hourly averages from a continuous PM2.5 monitor.


Auto calibration
Simplified automatic calibration using internal valves, ideal for remote locations
Fully integrated package including:
internal sample pump, sample heater, internal calibration valves, zero air pump & data logger
Internal sample heater
Internal sample heater with temperature or RH control, which can be enabled by the user to eliminate the effects of humidity (RH: < 30 to < 90 % )
12 VDC operation (45 W max, 13 W nominal)
Remote controle
Remote control through serial interface

See our technology in action

Schedule a free demo to get a first-hand look at how our solutions support your business.

Light Source

The Aurora 2000 can be equipped with any one of the following LED light sources:

  • 450 nm (blue) for fine & ultra fine particulates (wood fires, automobiles)
  • 525 nm (green) for visibility
  • 635 nm (red) for large particulates (e.g. pollen).


Aurora 2000 PM2.5 Nephelometer — manual correction factor configuration
In applications where the aerosol chemistry is stable, a correction factor can be manually entered which then provides excellent results with minimal maintenance and a high degree of correlation.

Aurora 2000 automatic correlating PM nephelometer configuration

In applications where aerosol chemistry is subject to change, a correction factor derived from manual sampling may be unreliable. In this case the Aurora 2000 may be connected directly to a PM2.5 compliance monitor, either the Acoem Spirant BAM or the Met One BAM 1020, in order to monitor and log PM hourly averages generated by the BAM (PMBAM). These hourly averages are compared to the Aurora’s hourly average scattering coefficient (σscat) and a scattering to PM coefficient factor (σscat/PM) is calculated.

This factor is then applied to the next hour of 1 minute scattering coefficients measured in order to determine a 1 minute average for PM concentrations (PMaurora).

The derived correction factor can also be used to determine changes in aerosol sources through deviations in light scattering from the expected values.

This configuration of the Aurora 2000 nephelometer provides the following parameters:

  • US EPA compliance data for PM2.5 measurement
  • Scattering coefficient (σscat)
  • BAMPM averages – 1 hour average only
  • Corrected real time 1 minute PM concentrations PMaurora
  • Sample temperature, relative humidity & barometric pressure.

Communications & Data storage

  • Outputs:
    • 25 pin external I/O analog outputs (2 voltage & 2 current)
    • 2 x RS232 serial ports (multi-drop, service)
  • Filtering: Kalman (digital adaptive filter), moving average (30 seconds) & no filter
  • Stored parameters: Date & time, µg/m3, σsp (635, 525 or 450 nm), hourly BAM PM average, hourly mass correction factor,
    sample air temperature, enclosure temperature, RH & barometric pressure & instrument status
  • Capacity: Maximum of 48 days of 5 minute averages, or 10 days of 1 minute averaged data.


  • Exhaust tubing kits
  • External pump & pump controller kit
  • Automated ball valve (sample bypass)
  • Roof flange kit & rain cap with insect screen
  • Gas calibration kit
  • Wall mount bracket.

World-class aerosol monitoring & measurement

Around the world, atmospheric scientists and environmental agencies, rely on Acoem’s range of Aurora™ integrating nephelometers every day.

Accurate, flexible and easy to operate, they are also transportable and designed to cope with the demands of use in remote locations.

Request pricing

Connect with Acoem

Contact us to learn more about our solutions, services, and training programs.

Would you like to…?