•eBC: equivalent black carbon mass concentration, an estimation of EC mass to represent EC by evolve gas analysis (EGA), which is different from EC by NIOSH and IMPROVE.

•b_ATN: light attenuation coefficient on filter.

•b_abs: light absorption coefficient in the air.

•SACS: specific attenuation cross section (also known as the sigma in the Aethalometer manual), represents the conversion factor between light attenuation on filter (b_ATN) and eBC.

•MAE: mass absorption efficiency, also know as mass absorption cross section (MAC), represents the conversion factor between light absorption in the air (b_abs) and eBC/EC.

•C_ref: conversion factor between b_ATN and b_abs, which is a result of the multiple scattering effect of the filter matrix.