COALA-2020: Measurements of aerosol composition by ACSM at Cataract Scout Park, NSW, January-March 2020

Measurements of aerosol chemical composition were captured using a Time-of-Flight Aerosol Chemical Speciation Monitor (Aerodyne Research Inc., Billerica, MA, USA). Measurements were taken at Cataract Scout Park, Appin, N.S.W. (34°14'42.29S 150°49'24.97E) from a common aerosol inlet manifold 5.13 m above ground level as part of the Characterizing Organics and Aerosol Loading over Australia (COALA-2020) campaign. Data processing was handled by the native Aerodyne software (Tofware v3.2.40210). Measurements were taken at 10-minute time resolution and down sampled to 1-minute means, as reported here. Down sampling occurred using cubic spline interpolation. The ACSM is sensitive to aerosol in the 40 – 1000 nm vacuum aerodynamic diameter range and drew sample air from the common aerosol bypass inlet at a flow rate of 85 mL min-1. Sampled air was dried using a Nafion dryer to less than 40% RH before sampling. Aerosol mass concentrations of organics, chloride, ammonium, nitrate and sulphate were retrieved. Reported errors are calculated using Tofware and are based on the number of counts recorded at each mass value and takes into account the subtraction of the background signal from the sample signal. Note however that noting the ion counts are determined from a measurement of current so that the uncertainty associated with converting the ampere signal to ion counts is also accounted for in the uncertainty calculation.