Extended Data Fig. 1: Data analysis stream used in this study.
From: Substantial contribution of transported emissions to organic aerosol in Beijing
Chemical characterizations of ToF-ACSM and FIGAERO-CIMS are used to quantify the sources of primary and secondary OA. We combine the quantitative OA ToF-ACSM analyses with a factorization of time series of near-molecular organic aerosol mass spectra determined by FIGAERO-CIMS. The ToF-ACSM is used to determine the organic mass and the contribution of primary organic aerosol (POA) from liquid fossil fuel combustion (HOA) and cooking (COA); the FIGAERO-CIMS is used to produce a set of SOA sources besides POA from solid-fuel combustion, which are converted into mass loadings using a multilinear regression to the ToF-ACSM OA mass loadings, once some of the POA sources (HOA, COA) have been subtracted from it. Thereby, we obtain response factors of the FIGAERO-CIMS to the different SOA sources. Were these to be single compounds (instead of SOA sources), the response factors would be calibration factors but here they were applied across a wide range of compounds contained in a specific SOA source in this instance.
