PMID- 11262437
OWN - NLM
STAT- MEDLINE
DCOM- 20010521
LR  - 20131121
IS  - 0894-2684 (Print)
IS  - 0894-2684 (Linking)
VI  - 13
IP  - 4
DP  - 2000 Winter
TI  - Comparison of nebulized particle size distribution with Malvern laser diffraction 
      analyzer versus Andersen cascade impactor and low-flow Marple personal cascade 
      impactor.
PG  - 303-14
AB  - Particle size of nebulized aerosols can be measured directly using laser 
      diffraction or by evaluating aerodynamic properties by cascade impaction. As of 
      today, there are no generally accepted standards for measuring particle size 
      distribution from nebulizers. Laser diffraction has been questioned because of 
      potential evaporative losses of the small particles at the edge of the plume, 
      causing an apparent shift in the particle size distribution and thus a larger 
      mass median diameter (MMD). When particle-sizing wet aerosols, cascade impaction 
      may give rise to an apparent shift in the distribution, resulting in a smaller 
      mass median aerodynamic diameter (MMAD) due to evaporative losses of aerosol 
      droplets as they enter the impactor at ambient temperature. The modified low-flow 
      Marple 296 Personal Cascade Impactor (MPCI) is currently being proposed as the 
      European standard for wet aerosol analysis to minimize evaporative losses during 
      sampling. The present study compared the particle size distribution of salbutamol 
      and sodium cromoglycate aerosols nebulized by the Pari LC Star, using laser 
      diffraction (Malvern Mastersizer X; MMX) and cascade impaction (Andersen Cascade 
      Impactor [ACI] and the commercially available MPCI), which was either at ambient 
      temperature or cooled to the nebulized aerosol temperature (10 degrees C). MMDs 
      obtained with the MMX were virtually identical to the MMADs measured with both 
      impactors when cooled with no significant differences in geometric standard 
      deviation (sigma(g)). When the impactors were operated at ambient temperature, 
      MMADs were smaller (18 to 30%) with a significantly larger sigma(g) (p < 0.05) 
      compared to the MMX. These findings suggest that droplet distribution data for 
      wet aerosol where evaporation process has not been minimized must be viewed with 
      caution. There was no evidence suggesting a significant evaporative loss of small 
      droplets from the edge of the plume during laser particle sizing. The MPCI does 
      not minimize evaporative losses of aerosol particles during sampling.
FAU - Kwong, W T
AU  - Kwong WT
AD  - Divisions of Respiratory Medicine and Lung Biology Research, Research Institute, 
      Hospital for Sick Children and the University of Toronto, Toronto, Ontario, 
      Canada.
FAU - Ho, S L
AU  - Ho SL
FAU - Coates, A L
AU  - Coates AL
LA  - eng
PT  - Comparative Study
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - J Aerosol Med
JT  - Journal of aerosol medicine : the official journal of the International Society 
      for Aerosols in Medicine
JID - 8809251
RN  - 0 (Aerosols)
RN  - 0 (Anti-Asthmatic Agents)
RN  - 0 (Bronchodilator Agents)
RN  - Q2WXR1I0PK (Cromolyn Sodium)
RN  - QF8SVZ843E (Albuterol)
MH  - Aerosols/administration & dosage
MH  - Albuterol/administration & dosage
MH  - Anti-Asthmatic Agents/administration & dosage
MH  - Bronchodilator Agents/administration & dosage
MH  - Cromolyn Sodium/administration & dosage
MH  - Humans
MH  - Lasers
MH  - *Nebulizers and Vaporizers
MH  - *Particle Size
EDAT- 2001/03/23 10:00
MHDA- 2001/05/25 10:01
CRDT- 2001/03/23 10:00
PHST- 2001/03/23 10:00 [pubmed]
PHST- 2001/05/25 10:01 [medline]
PHST- 2001/03/23 10:00 [entrez]
AID - 10.1089/jam.2000.13.303 [doi]
PST - ppublish
SO  - J Aerosol Med. 2000 Winter;13(4):303-14. doi: 10.1089/jam.2000.13.303.