Aurora 2000 PM 2.5 CORRELATING NEPHELOMETER BENEFITS • 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). Light Source The Aurora 2000 PM 2.5 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 PM 2.5 concentrations. This improves the correlation between the Aurora and Reference PM 2.5 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 PM 2.5 monitor. 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). CONFIGURATIONS Aurora 2000 PM 2.5 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 PM 2.5 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 (PM BAM ). These hourly averages are compared to the Aurora’s hourly average scattering coefficient (σ scat ) and a scattering to PM coefficient factor (σ scat /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 (PM aurora ). 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 PM 2.5 measurement • Scattering coefficient (σ scat ) • BAM PM averages – 1 hour average only • Corrected real time 1 minute PM concentrations PM aurora • Sample temperature, relative humidity and barometric pressure.