GRASP has been joined in partnership with the cutting edge instrument building company Airphoton (soon to be GRASP NA). This is a selection of the most advanced instruments for air quality control and the study of atmospheric particulate matter:

Aeroexplorer System

The AirPhoton AeroExplorer System measures aerosols in real time using a 3 wavelength integrating Nephelometer as well as collecting and preserving the aerosols themselves for later analysis using one of our filter stations. Aerosols sizes for sampling in either device can be selected using either standard inlets or cyclone inlets for a more sharply defined size cutoff. The aerosols collected for later analysis are preserved within a cartridge assembly. The cartridge can be configured to collect all samples on a single filter or to use a two stage filter which further divides the particles into fine and coarse size ranges. The cartridge is mailed intact for analysis virtually eliminating contamination issues.


Small and compact AirPhoton Integrating Nephelometers are our highest quality scientific instrument, enclosed in an environmentally protected case, ready for outdoor deployment in rugged conditions. They have been deployed in the Antarctic, the Swiss Alps and the Himalayan Mountains as well as hot and humid tropical conditions in Brazil and Singapore. Our unique design allows us to make completely separate and useful measurements in both the forward and backward scattering directions. Measurements are made in three wavelengths 450nm, 532 nm and 632 nm, over the angular range 7 to 170 ° and to a sensitivity <10-7m-1. Internal sensors measure and record temperature, relative humidity and pressure.

Power requirements are 25W @ 120 VAC and input power options include: 110/220 VAC, 50/60Hz with the provided power supply. Other powering options can be made available upon request such as operating from batteries or solar power. Optional heaters are available at the expense of additional power consumption. Data from our integrating nephelometers is saved in a removable SD memory card and can be linked to an external computer via RS485 using AirPhoton optional accessories. Bluetooth and RS232 options are available upon request. AirPhoton nephelometers can be linked to the AeroExplorer filter sampling station to sync data time series from both instruments.There are currently 4 models of nephelometers to choose from as described in the table below.

Filter Stations

The AirPhoton Explorer Automated Filter Sampling Station is a fully programmable system that collects particulate matter on filters for subsequent analysis. Consisting of a Inlet/Filter unit and a Control box, the station is designed for compatibility with the AirPhoton 8-slot filter cartridge model FC10. The programmable capability allows flexibility when designing sampling cycles, moving collection from filter slot to filter slot or turning collection on and off at specified times.

Laser Imaging Nephelometer

The AirPhoton Laser-Imaging Nephelometer is a unique instrument which offers full particle characterization including size distribution and the complex refractive index. It can be used in any controlled environment such as a laboratory, aircraft or shipboard.