Sampled air enters the inlet cowl and accelerates through six radial slots in the first impactor stage. The cowl eliminates ashes and debris from the sampler. Particles larger than the cut-point of the first stage impact on the pre-cut collection substrate. The air flows through the narrower slots in the second impactor stage and smaller particles impact on the second collection substrate. This process continues to the final filter. The width of the radial slots is constant for each stage but smaller for each succeeding stage. The jet velocity is higher for each succeeding stage, and smaller particles eventually acquire sufficient momentum to impact on the collection substrates. After the last impactor stage, remaining fine particles are collected on the built-in 34mm filter.
Prior to sampling, collection substrates and the back-up filter are weighed and placed in the impactor. A commercial-type personal air sampler pump with a flow range from 0.5 to 5 liters will accommodate the New Star Marple Personal Cascade Impactors. The typical flow rate is set at 2 lpm (liters per minute). The impactors personal mounting bracket is attached to the lapel or pocket.
After sampling, the substrates and filters are weighed. Weight increase on each substrate is the mass of the particles for that impactor stage. The total weight of particles on all stages and final filter is added and the percent particle mass in each size range is calculated. Respirable particle mass fraction is determined from the particle size distribution.
- Wood dust
- Coal dust
- Silica dust
- Respirable dust sampling
- Inhalation toxicology
- Indoor air pollution
- Aerosol research
A multi-jet, multi-stage personal cascade impactor
||2 liters per minute (lpm) nominal; 1-5 lpm flow range (1-3 lpm recommended)
||34 mm diameter, Mylar, stainless steel, glass fiber, and other filter media
||34 mm diameter; PVC filter media, 5 micron pore size and glass fiber