American Ecotech - Model 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 LED light source to measure aerosol light scattering and derive particulate concentrations. The Aurora™ 2000 enables a correction factor to be used in order to derive PM2.5 concentrations. This improves the correlation between the Aurora™ and Reference PM2.5 methods while providing 1 minute measurements from the Aurora™ 2000. The correction factor can be entered manually or automatically derived from hourly averages from a continuous PM2.5 monitor.
- 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 and data logger
- 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 watts max, 13 watts nominal).
The Aurora™ 2000 can be equipped with any one of the following LED light sources:
- 450 nm (blue) for fine and 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 ECOTECH 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 and barometric pressure.
- Measured parameters: \ig/m* and oScaI
- Ranges: o - 2000 LJg/m* and o - 20,000 Mm'
- Lower detectable limit: 3 |ig/m3 (<o.3 Mm 0 (60 second averaged data)
- Secondary measurements: Sample air temperature, relative humidity (RH), barometric pressure and enclosure temperature
- Flow rate: -51/min with default blower. Higher flow can be obtained using the external pump option
- (e.g. in case of common inlet)
- Operating temperature: -20 to 45 °C
- Operating RH: 10 to 95 %
- Calibration: Span gas available for C02, SF6, FM-200, R-12, R-22, R-134 or a user defined gas
- Optics: Reference light source measurement
- Light source: Stable LED light source (US patent 7,671,988)
- Wavelength: 525 nm (green), 450 nm (blue) or 635 nm (red)
- Operating voltage: 12 VDC (incl no - 240 VAC 50/60 Hz power supply converter)
- Power consumption: 13 watts nominal, 45 watts with heater active
- Dimensions: 170 x700 x215 mm
- Weight: 11.2 kg
- 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) and no filter
- Stored parameters: Date & time, ng/m?, osp (635,525 or 450 nm), hourly BAM m average, hourly mass correction factor, sample air temperature, enclosure temperature, RH and barometric pressure and instrument status
- Capacity: Maximum of 48 days of 5 minute averages, or 10 days of 1 minute averaged data.
- Solar power option
- Roof flange kit and rain cap with insect screen
- Gas calibration kit
- Wall mount bracket.