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MA350 Aethalometer

The MA350 is an advanced aethalometer that measures black carbon concentrations at multiple wavelengths and provides source apportionment between fossil fuel and biomass burning sources.

Data Format

  • File format: CSV file
  • Sampling frequency: Variable
  • File naming pattern: *.csv
  • Data structure:
    • Datetime index from 'Date / time local' column
    • BC measurements at multiple wavelengths
    • Source apportionment data
    • Derived parameters

Measurement Parameters

The MA350 provides:

  • Black carbon measurements at five wavelengths:
    • UV (BC1)
    • Blue (BC2)
    • Green (BC3)
    • Red (BC4)
    • IR (BC5)
  • Source apportionment:
    • Biomass burning BC mass (BB mass)
    • Fossil fuel BC mass (FF mass)
  • Derived parameters:
    • Delta-C (UV-IR difference)
    • AAE (Absorption Ångström Exponent)
    • BB (Biomass burning percentage)

Data Processing

Data Reading

  • Processes CSV files with specific header structure
  • Standardizes column names
  • Maps wavelength-specific measurements
  • Handles datetime parsing
  • Converts measurements to numeric format

Quality Control

  1. Instrument Status Check:

    • Filters data based on instrument status codes:
      • Status = 1: Power Failure
      • Status = 2: Start up
      • Status = 4: Tape advance
      • Status = 16: Optical saturation
      • Status = 32: Sample timing error
      • Status = 128: Flow unstable
      • Status = 256: Pump drive limit
      • Status = 2048: System busy
      • Status = 8192: Tape jam
      • Status = 16384: Tape at end
      • Status = 32768: Tape not ready
      • Status = 65536: Tape transport not ready
      • Status = 262144: Invalid date/time
      • Status = 524288: Tape error
    • Removes data points with other status codes indicating instrument problems

  2. Value Range Check:

    • Removes physically impossible values:
      • Negative concentrations
      • Values > 20000 ng/m³

  3. Data Representativeness:

    • Requires at least 50% of expected data points in each 1-hour window
    • Ensures temporal consistency of measurements

  4. Complete Record Requirement:

    • Ensures data completeness across all channels
    • Validates source apportionment calculations

Output Data

The processed data contains:

  • Time index: Data acquisition time
  • BC1-BC5: Black carbon at each wavelength (ng/m³)
  • BB mass: Biomass burning BC (ng/m³)
  • FF mass: Fossil fuel BC (ng/m³)
  • Delta-C: UV-IR difference (ng/m³)
  • AAE: Absorption Ångström Exponent
  • BB: Biomass burning percentage (%)

Notes

  • Provides real-time source apportionment
  • Distinguishes between fossil fuel and biomass burning
  • Multi-wavelength measurement capability
  • Advanced data quality control
  • Source-specific mass concentrations