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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.

AeroViz.rawDataReader.script.MA350.Reader 

Reader(path: Path | str, reset: bool | str = False, qc: bool | str = True, **kwargs)

Bases: AbstractReader

MA350 Aethalometer Data Reader

A specialized reader for MA350 Aethalometer data files, which measure black carbon at multiple wavelengths and provide source apportionment.

See full documentation at docs/source/instruments/MA350.md for detailed information on supported formats and QC procedures.

Attributes

nam class-attribute instance-attribute 

nam = 'MA350'

BC_COLUMNS class-attribute instance-attribute 

BC_COLUMNS = ['BC1', 'BC2', 'BC3', 'BC4', 'BC5']

ABS_COLUMNS class-attribute instance-attribute 

ABS_COLUMNS = ['abs_375', 'abs_470', 'abs_528', 'abs_625', 'abs_880']

CAL_COLUMNS class-attribute instance-attribute 

CAL_COLUMNS = ['abs_550', 'AAE', 'eBC']

MIN_BC class-attribute instance-attribute 

MIN_BC = 0

MAX_BC class-attribute instance-attribute 

MAX_BC = 20000

MIN_AAE class-attribute instance-attribute 

MIN_AAE = 0.7

MAX_AAE class-attribute instance-attribute 

MAX_AAE = 2.0

ERROR_STATES class-attribute instance-attribute 

ERROR_STATES = [1, 2, 4, 16, 32, 128, 256, 2048, 8192, 16384, 32768, 65536, 262144, 524288]

Functions

_raw_reader 

_raw_reader(file)

Read and parse raw MA350 Aethalometer data files.

Parameters:

Name Type Description Default
file Path or str

Path to the MA350 data file.

 required

Returns:

Type Description
DataFrame

Processed MA350 data with datetime index and standardized black carbon and source apportionment columns.

_QC 

_QC(_df)

Perform quality control on MA350 Aethalometer raw data.

QC Rules Applied (raw data only)
  1. Status Error : Invalid instrument status codes
  2. Invalid BC : BC concentration outside 0-20000 ng/m³
  3. Insufficient : Less than 50% hourly data completeness

Note: AAE validation is done in _process() after calculation.

_process 

_process(_df)

Calculate absorption coefficients and validate derived parameters.

Processing Steps
  1. Calculate absorption coefficients at each wavelength
  2. Calculate AAE (Absorption Ångström Exponent)
  3. Calculate eBC (equivalent Black Carbon)
  4. Validate AAE range and update QC_Flag

Data Format

  • File format: CSV file
  • Sampling frequency: 1 minute
  • 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:

Column Wavelength Description
BC1 375 nm UV channel
BC2 470 nm Blue channel
BC3 528 nm Green channel
BC4 625 nm Red channel
BC5 880 nm Near-IR channel (reference)

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

The MA350 reader uses the declarative QCFlagBuilder system with the following rules:

+-----------------------------------------------------------------------+
|                            _QC() Pipeline                             |
+-----------------------------------------------------------------------+
|                                                                       |
|  [Pre-process] Calculate absorption coefficients, AAE, eBC            |
|       |                                                               |
|       v                                                               |
|  +---------------------+    +---------------------+                   |
|  | Rule: Status Error  |    | Rule: Invalid BC    |                   |
|  +---------------------+    +---------------------+                   |
|  | Bitwise status      |    | BC <= 0 OR          |                   |
|  | code filtering      |    | BC > 20000 ng/m³    |                   |
|  +---------------------+    +---------------------+                   |
|           |                          |                                |
|           v                          v                                |
|  +---------------------+    +---------------------+                   |
|  | Rule: Invalid AAE   |    | Rule: Insufficient  |                   |
|  +---------------------+    +---------------------+                   |
|  | AAE < -2.0 OR       |    | < 50% hourly data   |                   |
|  | AAE > -0.7          |    | completeness        |                   |
|  +---------------------+    +---------------------+                   |
|                                                                       |
+-----------------------------------------------------------------------+

QC Rules Applied

Rule Condition Description
Status Error Bitwise status code check Invalid instrument status codes detected
Invalid BC BC ≤ 0 OR BC > 20000 ng/m³ BC concentration outside valid range
Invalid AAE AAE < -2.0 OR AAE > -0.7 Angstrom exponent outside valid range
Insufficient < 50% hourly data Less than 50% hourly data completeness

Error Status Codes

Code Description
1 Power Failure
2 Start up
4 Tape advance
16 Optical saturation
32 Sample timing error
128 Flow unstable
256 Pump drive limit
2048 System busy
8192 Tape jam
16384 Tape at end
32768 Tape not ready
65536 Tape transport not ready
262144 Invalid date/time
524288 Tape error

Output Data

The processed data contains the following columns:

Column Unit Description
BC1-BC5 ng/m³ Black carbon at 5 wavelengths
abs_375-880 Mm⁻¹ Absorption coefficients
abs_550 Mm⁻¹ Interpolated absorption at 550nm
AAE - Absorption Angstrom Exponent
eBC ng/m³ Equivalent black carbon

QC_Flag Handling

  • The intermediate file (_read_ma350_qc.pkl/csv) contains the QC_Flag column
  • The final output has invalid data set to NaN and QC_Flag column removed

Notes

  • Provides real-time source apportionment
  • Distinguishes between fossil fuel and biomass burning
  • Multi-wavelength measurement capability (5 channels)
  • Advanced data quality control with QCFlagBuilder