Quantifying errors in the aerosol mixing-state index based on limited particle sample size

J. T. Gasparik, Q. Ye, J. H. Curtis, A. A. Presto, N. M. Donahue, R. C. Sullivan, M. West, and N. Riemer

Aerosol Science and Technology 54(12), 1527-1541, 2020.

This study evaluates the error that is introduced in quantifying observed aerosol mixing states due to a limited particle sample size. We used the particle-resolved model PartMC-MOSAIC to generate a scenario library that encompasses a large number of reference particle populations with a wide range of mixing states quantified by the mixing-state index χ. We stochastically sub-sampled these particle populations using sample sizes of 10 to 10,000 particles and recalculated χ based on the sub-samples. The finite sample size led to a consistent overestimation of χ, with the 95% confidence intervals ranging from −70 to 30 percentage points for sample sizes of 10 particles, and decreasing to ±10 percentage points for sample sizes of 10,000 particles. These findings were experimentally confirmed with single-particle measurements from the Pittsburgh area using a soot-particle aerosol mass spectrometer.

DOI: 10.1080/02786826.2020.1804523

Full text: GaYeCuPrDoSuWeRi2020.pdf