Evaluation of pump pulsation in respirable size-selective sampling: part II. Changes in sampling efficiency

Area of Science:

• Occupational hygiene
• Aerosol science
• Industrial safety

Background:

• Personal sampling pumps generate air pulsations affecting respirable particle sampler efficiency.
• Previous work characterized pump pulsations, necessitating evaluation of their impact on sampling efficiency.

Purpose of the Study:

• To evaluate changes in sampling efficiency of respirable size-selective samplers due to pump-generated air pulsations.
• To compare current European standards for pump pulsation criteria with experimental findings.

Main Methods:

• Used monodisperse ammonium fluorescein particles (1-9 µm) with 10-mm Dorr-Oliver (DO) cyclones and five medium flow pumps with varying pulsations (5%-70%).
• Employed GK2.69 cyclones with high flow pumps (Legacy: 15% pulsation, Elite12: 41% pulsation).
• Measured fluorescein intensity using a luminescence spectrometer to determine sampling efficiencies and generated bias maps.

Main Results:

• No significant change in sampling efficiency (bias < ±10%) was observed for the DO cyclone until pulsations exceeded 25%.
• Pumps with 30%, 56%, and 70% pulsations caused substantial changes in sampling efficiency.
• The GK2.69 cyclone showed similar trends, with no change at 15% pulsation but significant changes at 41% pulsation.

Conclusions:

• A pulsation criterion of 25% may be acceptable for respirable particle collection with DO cyclones.
• Current European standards (10% pulsation) may be overly restrictive and unachievable for many pumps.
• Further research is recommended to establish appropriate pulsation criteria for international standards.