Aurora Nephelometer

Aerosols in the atmosphere influence the radiative balance through direct scattering of solar radiation and indirect effects in the formation of clouds and precipitation. The measurement of back and total scattering from aerosols provide in depth analysis of their optical properties and their effect on the global energy balance

Ecotech, through collaboration with globally renown atmospheric research institutes, provides the scientific community with the most advanced commercially available nephelometers.

The Aurora series of integrating nephelometers is far more than a single instrument providing:

• Models that measure the scattering coefficient for a single wavelength (Aurora 1000) and hence derive visibility measurements.
• A multiple wavelength instrument (Aurora 3000) capable of providing information on total scatter as well as backscatter.
• A system of two nephelometers with humidity control and comparison from the one sample stream.
  
• An instrument now capable of measuring aerosol scattering at a variety of different angles (Aurora 4000 Polar).

Ecotech provides the broadest and most cost effective range of nephelometers on the market Easy to install, operate, maintain and service. The Aurora nephelometer series gives you the accuracy you need at the price you want.

Aurora 1000 Nephelometer (single wavelength)

Aurora 2000 Nephelometer (PM2.5 correlation)

Aurora 3000 Nephelometer (3 wavelengths with backscatter)

Aurora 4000 Nephelometer (polar nephelometer)

ACS1000 Aerosol Conditioning System (Wet/dry nephelometry)

What is a Nephelometer?

The integrating nephelometer provides a means of measuring light scattering coefficients of ambient aerosol particles with a high sensitivity and time resolution in a wide range of monitoring and research applications related to air pollution and climate. Accurate, direct measurements of the scattering and absorption coefficients of atmospheric aerosol particles are of importance for determining how particles affect radiative transfer and visibility in the atmosphere.

The integrating nephelometer, as devised by Beuttell and Brewer (1949), measures the particulate scattering coefficient, ?sp, by performing a geometrical integration of the light scattered from a sample volume illuminated by a Lambertian light source that is orthogonal to the axis of the detector. As such, the nephelometer provides a direct measure of scattering coefficient independent of the size, chemical composition, and physical state of the aerosol in an enclosed volume and it can be calibrated by gases with known scattering coefficients.

Why use an LED diffusion source instead of a flash lamp?

• Our LED light source is guaranteed not to fail and often exceeds 5 years compared to a flash lamp that is recommended to be changed every 4-6 months.
• Heat generated by the LED light source is a fraction of that generated by a flash lamp, minimising changes in sample relative humidity.
• LEDs emit light at a specific wavelength eliminating the need for band pass filters.

More Information

The light source used in the Aurora nephelometer is a patented LED opal glass light source which was designed for the Aurora range of nephelometers as it achieves a lambertian distribution as close as possible to ideal (light intensity is the same in every direction).  With rapid improvements in LED technology, it has been possible to obtain higher intensity outputs from smaller LED packages and as such, the lightsource has just 3 LEDs for each wavelength.   It is preferable over the older flash lamp technology for several reasons:

• Our LED light sources generate a fraction of the heat generated by halogen flash lamps.  This is a critical element when considering the impact that temperature and humidity can have on hygroscopic aerosols.
• The LED light source is extremely robust, reliable and has been demonstrated to last well inexcess of 5 years without replacement. Halogen lamps are recommended for replacement every 6 months. Considering the remote location of some integrating nephelometers, this reduction in maintenance is very significant.
• The LED array also eliminates the need for narrow bandpass optical filters due to the LEDs intrinsic wavelength selectivity.