Since light absorption could be attributed solely to Black Carbon at the near infrared channel [Hansen et al., 1984; Weingartner et al., 2003; Favez et al., 2009], the measurement at the 880 nm wavelength, which was considered as the standard channel for Black Carbon measurements, was only used for the determination of concentration. The Aethalometer was operated at 5 l/min with an inlet placed at 3.0 m height above ground grassland.