An affordable, water-based, community condensation particle counter

Area of Science:

• Atmospheric Science
• Environmental Monitoring
• Instrumentation

Background:

• Accurate measurement of airborne particle number concentrations is crucial for understanding air quality and climate.
• Existing condensation particle counters can be expensive, limiting widespread deployment.
• Development of affordable and reliable particle monitoring instruments is needed.

Purpose of the Study:

• To introduce and evaluate a novel, affordable Community Condensation Particle Counter (cCPC).
• To assess the cCPC's performance in detecting and quantifying airborne particles, particularly smaller sizes.
• To compare the cCPC's measurements with established instruments under ambient and laboratory conditions.

Main Methods:

• The cCPC utilizes an expansion-type condensation particle counting method with single particle detection.
• Particle number concentrations are calculated from droplet detection, pressure readings, and cell volume.
• Performance was evaluated through modeling, experimental detection limits, ambient sampling, and laboratory comparisons with benchtop instruments.

Main Results:

• The cCPC detects particles as small as 4 nm, with over 95% detection efficiency for particles >20 nm.
• Ambient sampling showed high agreement between two collocated cCPCs (3.5% pooled standard deviation).
• Comparison with ADI MAGIC CPCs yielded a high correlation (R²=0.98) and a regression slope of 1.1.

Conclusions:

• The developed cCPC offers an affordable solution for monitoring airborne particle number concentrations.
• The instrument demonstrates reliable performance and high detection efficiency for ambient aerosols.
• Discrepancies observed in laboratory studies at high concentrations require further investigation.