Mass Absorption Efficiency of PM1 in Mexico City during ACU15

From January to March 2015, an atmospheric aerosol measurement campaign, “Aerosoles en Ciudad Universitaria 2015” (ACU15), was carried out in Mexico City determine the particles’ optical properties and chemical composition. Two photoacoustic spectrometers measured scattering absorption coefficient at two different wavelengths. The average 532 nm 12.71 ± 9.48 Mm−1 870 10.35 7.36 Mm−1. 65.63 47.12 (532 nm) 21.12 14.24 (870 nm). composition determined via speciation monitor. organic fraction represented 53% of total PM1 made up 63% low volatile (4.64 µg m−3), 22% hydrogenated (1.90 15% semi-volatile organics (1.54 m−3). correlation species (NO3−, NH4+, SO42−, low-volatile, organics) 0.92. multilinear regression showed a good agreement among (r > 0.7). mass calculated for measuring site MAE870 = 5.8 m2 g−1, instead default 4.74 g−1. Furthermore, based on median AAE, MAE532 resulting from multiple linear (MLR) following coefficients: 7.70 g−1 (eBC), 0.22 (HOA), 0.16 (LV–OOA). coefficients MLR were: 7.08 5.83 (NO3−), 5.69 (low aerosol), 2.78 (SO42−), 2.40 (hydrocarbon-like 1.04 (semi aerosol).