High Resolution Aerosol Mass Spectrometer (HRToF-AMS)

Tehcnical Specifications

Dimensions in cm: 105 x 61 x 135

Weight: about 170 Kg. (about 280 Kg in its shipping box)

Universal Power Supply: 110VAC/60Hz o 220VAC/50 Hz

Vacuum System operates at 24 VDC

Electric power: about 600W

Granulometric Classification and Chemical Analysis of Sub-micronic Aerosol Particles

Aerodynamic Range: 40 nm – 1 µm

ToFMS: The spectrometer during flight time can work in low-resolution configuration (V) or high resolution (W):

 Limit of Detection   Resolution

  Mass Range

HR-ToF-AMS (V-mode)   0.003

  Unitaria (1000)

HR-ToF-AMS (W-mode)   0.05   4000   1-1200

Detection limits are determined every minute with a three to one S/N ratio. Limits are calculated using nitrate ions, and the collection efficiency for each chemical compound can be determined by referring to a database. In this database, each organic and inorganic species has been measured in relationship to Ammonium Nitrate. This inorganic compound has been selected due to its chemical reactivity in aerosol, and because it is used for calibrating the instrument. Detection limits depend on the operation mode of the HR-ToF-AMS, but for nitrates they are about 3 ng/m3 (in V-mode) and 30 ng/m3 (in W-mode). Organic species show detection limits about 10 times higher for both modes, sulfates show 2 to 4 times the limits, and ammonium 5 to 10 times.

Parameters Measured and Output Formats:

All modifications are provided in HDF (Hierarchical Data Format) and applications are run using IGOR Pro 6.2

  • The distribution of aerodynamic aerosols ranges from 40nm – 1 micron
  • Parameters measured include spectral mass data for inorganic substances (nitrates, sulfates, ammonium) and speciation of organic substances for classes of compounds (saturated and unsaturated hydrocarbons, oxygenated hydrocarbons, etc..)
  • The instrument can determine the composition of elements (O: C, H: C)

The instrument is portable and can be placed in vans and on small platforms. Due to its high acquisition speed, the instrument can create high-resolution maps using commerical-sized airliners.

By acquiring vertical profiles, it is possible to study the correlation between an aerosol’s chemical composition and the optical properties of the particulates.

For example, the AMS is able to determine information relating to the hygroscopicity of particular matter, as moisture will affect its optical properties. As a result, the AMS is able to instantly determine not only the water content but also the presence of other chemical species. In this way one can calibrate images by satellite or by remote sensing, to generally improve what these images can offer in regard to chemical composition.

In addition, in laboratory tests the AMS evaluates kinetic formations of particulate matter, and it can evaluate secondary phenomena like adsorption of chemical species on atmospheric particles.