Aerodynamic Particle Sizer (APS)

The APS is an instrument used for measuring aerodynamic particle size distributions in the micrometer range.

Data Format

• File format: Tab-delimited text file
• Sampling frequency: Variable
• File naming pattern: *.txt
• Data structure:
  • Header: 6 rows of metadata
  • Time columns: Date and Start Time
  • Size distribution data: Columns 3-54

Measurement Parameters

The APS provides aerodynamic particle size distribution measurements:

• Size range: 542-1981 nm
• Output: Number concentration for each size bin
• Total particle concentration (particles/cm³)

Data Processing

Data Reading

• Automatically skips header rows
• Parses date and time into datetime index
• Extracts particle size distribution data
• Rounds size bin values to 4 decimal places
• Validates datetime values

Quality Control

• Ensures temporal data completeness (minimum 5 measurements/hour)
• Applies total concentration thresholds (1-700 particles/cm³)
• Calculates total concentration with logarithmic bin spacing
• Removes invalid measurements

Output Data

The processed data contains:

• Time index: Data acquisition time
• Size bins: Number concentration for each particle size
• Total concentration: Integrated particle number concentration

Notes

• Measures aerodynamic particle diameter directly
• Complementary to SMPS for larger particle sizes
• Size range approximately 0.5-20 μm
• Logarithmic bin spacing in size distribution