CALIBRATION OF A MODIFIED ANDERSEN BACTERIAL AEROSOL SAMPLER.

Area of Science:

• Environmental Science
• Aerosol Science
• Microbiology

Background:

• The Andersen sampler is a widely used device for assessing airborne microbial contamination.
• Previous versions exhibited limitations in accurately sampling larger airborne particles, potentially skewing results.

Purpose of the Study:

• To identify and rectify defects in the commercial Andersen sampler's particle sampling capabilities.
• To enhance the instrument's performance for more accurate airborne particle size distribution analysis.

Main Methods:

• Investigated the flow regime within the commercial Andersen sampler.
• Redesigned the hole patterns of the upper stages and incorporated an additional stage.
• Developed a new, rational hole pattern for the lower stages.
• Introduced a colony-counting mask for improved assay efficiency.
• Calibrated the modified Andersen sampler system.

Main Results:

• Identified specific defects in the sampling of larger airborne particles.
• Achieved satisfactory sampling performance through redesigning hole patterns and adding a stage.
• Extended the effective sampling range of the instrument.
• Demonstrated the utility of a colony-counting mask for easier analysis.
• Presented a calibration method enabling particle size distribution curve generation.

Conclusions:

• The modified Andersen sampler design significantly improves the sampling of larger airborne particles.
• The enhanced instrument provides a more accurate assessment of airborne particle size distribution.
• The suggested modifications offer a practical solution for improving aerosol sampling accuracy.