Low flow rate sharp cut impactors for indoor air sampling: design and calibration
Two single round nozzle impactors have been developed for use in Harvard's indoor air pollution health study. Both impactors operate at flow rates of 4 L/m and are nearly identical, differing only in their cut size of 2.5 ..mu..m and 10 ..mu..m aerodynamic diameters. Two identical cascaded stages of the same cut size are used to obtain sharp cut-of characteristics. The particles are deposited on impaction plates made of oil impregnated, porous material to reduce particle bounce and are discarded. Only the particles collected on the afterfilter are analyzed. Special care has been taken to collect the particles uniformly on the afterfilter to aid in particle analysis. The impactors were calibrated with a vibrating orifice monodisperse aerosol generator. However, due to the sharp cut of the impactors, doublets and triplets in the calibration aerosols, even in small quantities, gave erroneous calibration curves. Therefore, the number of doublets and triplets in the challenging aerosols were measured and appropriate corrections made to the calibration curves.
- Research Organization:
- Univ. of Minnesota, Minneapolis (USA)
- OSTI ID:
- 5319742
- Journal Information:
- J. Air Pollut. Control Assoc.; (United States), Journal Name: J. Air Pollut. Control Assoc.; (United States) Vol. 37:11; ISSN JPCAA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Personal cascade impactor: design, evaluation and calibration
Calibration of a Monsanto cascade impactor with a monodisperse aerosol