Consistency of urban background black carbon concentration measurements by portable AE51 and reference AE22 aethalometers : effect of corrections for filter loading

Masey, Nicola and Ezani, Eliani and Gillespie, Jonathan and Sutherland, Fiona and Lin, Chun and Hamilton, Scott and Heal, Mathew R. and Beverland, Iain J. (2019) Consistency of urban background black carbon concentration measurements by portable AE51 and reference AE22 aethalometers : effect of corrections for filter loading. Aerosol and Air Quality Research. ISSN 2071-1409 (In Press)

[img] Text (Masey-etal-AAQR-2019-Consistency-of-urban-background-black-carbon-concentration-measurements)
Masey_etal_AAQR_2019_Consistency_of_urban_background_black_carbon_concentration_measurements.pdf
Accepted Author Manuscript
Restricted to Repository staff only until 1 August 2020.

Download (3MB) | Request a copy from the Strathclyde author

    Abstract

    Measurement of exposure to black carbon with portable monitoring devices is an important part of research on the health impacts of combustion-related air pollutants. We collected 786 hourly-averaged equivalent black carbon (eBC) measurements from co-located duplicate portable AethLab AE51 aethalometers and a UK government reference Magee Scientific AE22 aethalometer (latter adjusted for filter darkening effects using a standard procedure for UK government AE22 aethalometers) at an urban background site in Glasgow, UK. AE51 and reference AE22 aethalometer concentrations were highly correlated (R2 ≥ 0.87) over the combined deployment periods. Application of a previously-reported method for correction of underestimation of concentrations by AE51 monitors associated with filter loading generally overestimated [corrected] reference AE22 aethalometer eBC concentrations (e.g. for two AE51 monitors normalised mean bias = +14% and +25% for literature-based correction method cf. -2% and +3% for unadjusted AE51 data across the full range of measurements). We found limited and inconsistent evidence for underestimation of eBC cf. corrected AE22 eBC measurements for the two AE51 instruments evaluated (for AE51 attenuation (ATN) ≤ ~52). Our observations suggest that the AE51 monitors we evaluated do not require correction for filter loading, at relatively low ATN values in environments with low eBC concentrations, to achieve close agreement with UK government corrected AE22 eBC measurements.