Organic Carbon/Elemental Carbon Analyzer (OC/EC)

The OC/EC analyzer measures carbonaceous aerosol components using thermal and optical methods.

Data Format

• File format: CSV file
• Sampling frequency: Variable
• File naming pattern: *.csv
• Data structure:
  • Header: 3 rows of metadata
  • Time column: Start Date/Time
  • Carbon fraction measurements
  • Sample volume information

Measurement Parameters

The OC/EC analyzer provides measurements of:

• Thermal analysis:
  • Organic Carbon (Thermal_OC)
  • Elemental Carbon (Thermal_EC)
• Optical analysis:
  • Organic Carbon (Optical_OC)
  • Elemental Carbon (Optical_EC)
• Carbon fractions:
  • OC1-4: Different temperature stages
  • PC: Pyrolyzed carbon
  • TC: Total carbon

Data Processing

Data Reading

• Processes CSV files with varying header structures
• Handles 12/24 hour time formats
• Standardizes column names
• Rounds timestamps to nearest hour
• Converts raw measurements to concentration units

Quality Control

• Removes physically implausible values (<-5 or >100 μgC/m³)
• Applies minimum detection limits:
  • Thermal_OC: 0.3 μgC/m³
  • Optical_OC: 0.3 μgC/m³
  • Thermal_EC: 0.015 μgC/m³
  • Optical_EC: 0.015 μgC/m³
• Uses time-aware IQR filtering
• Requires valid OC measurements

Output Data

The processed data contains:

• Time index: Data acquisition time
• Carbon measurements:
  • Thermal and optical OC/EC
  • Total carbon (TC)
  • Carbon fractions (OC1-4, PC)
• Sample volume: Air volume sampled

Notes

• Provides critical information about combustion sources
• Helps identify secondary organic aerosol formation
• Combines thermal and optical analysis methods
• Standardizes output across different instrument formats