Since light absorption could be attributed solely to BC 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 BC 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.