Assessment of biomass burning and fossil fuel contribution to black carbon concentrations in Delhi during winter

Characterizing Light-absorbing Aerosols in a Low-income Settlement in South Africa

“…Wang et al (2013) also found varying E (abs) values which ranged from 0.47 m 2 g -1 to 5.15 m 2 g -1 , signifying the effect of temporal and spatial variability on E (abs) measurements. E (abs) value of 7.7 m 2 g -1 measured at 880 nm, generally represents pure BC computed by Aethalometer instruments (Dumka et al, 2018;Dumka et al, 2019). If possible, sitederived E (abs) values are mostly preferred for long-term lightabsorbing aerosol measurements as they can improve the accuracy of quantifying BC particulates (Wang et al, 2013).…”

“…But the presence of other light-absorbing particles (for example, BrC-related polycyclic aromatic hydrocarbons (PAH)) leads to stronger absorption at short wavelengths (≤ 470 nm), and thus stronger short wavelength dependence is indicated by AAE > 1 ( Ramachandran and Rajesh, 2007). For example, wood burning-related aerosols are sensitive to short wavelengths and can be indicated by high AAE values which can range from 1.31 to 1.88 (Massabò et al, 2015;Dumka et al, 2018). The AAE measured at multiple wavelengths enables the apportionment of different light-absorbing aerosols contributing to the total mass concentration of the lightabsorbing fraction (Backman et al, 2014).…”

“…The AAE measured at multiple wavelengths enables the apportionment of different light-absorbing aerosols contributing to the total mass concentration of the lightabsorbing fraction (Backman et al, 2014). In this respect, the absorption wavelength dependences were calculated at 370/880 nm, 370/590 nm, 590/950 nm and 370/950 nm, which are commonly used to analyse chemical composition of the measured light-absorbing aerosols (Favez et al, 2010;Dumka et al, 2018). The 370/880 nm and 370/950 nm pair represents the average absorption wavelength behaviour of the measured particles and has been used widely for understanding source apportionment from residential fuel combustion (for example, Sandradewi et al, 2008;Yang et al, 2009;Favez et al, 2010;Tiwari et al, 2014;Dumka et al, 2018).…”

“…In this respect, the absorption wavelength dependences were calculated at 370/880 nm, 370/590 nm, 590/950 nm and 370/950 nm, which are commonly used to analyse chemical composition of the measured light-absorbing aerosols (Favez et al, 2010;Dumka et al, 2018). The 370/880 nm and 370/950 nm pair represents the average absorption wavelength behaviour of the measured particles and has been used widely for understanding source apportionment from residential fuel combustion (for example, Sandradewi et al, 2008;Yang et al, 2009;Favez et al, 2010;Tiwari et al, 2014;Dumka et al, 2018). However, there is no strong consensus on the strength of the relationship between specific AAE values and specific aerosol compositions (Kaskaoutis et al, 2007).…”

“…Lack of adequate information on light-absorbing particles contributes to the uncertainties associated with comprehensive assessment of the impacts of aerosols on human health and climate (Bergstrom et al, 2007;Wu et al, 2009;Yan et al, 2017;Laakso et al, 2012;Vakkari et al, 2014;Maritz et al, 2015;Maritz, 2019). Efforts to understand aerosol properties are applied increasingly worldwide (for example, Yang et al, 2009;Chakrabatry et al, 2010;Favez et al, 2010;Gadhavi and Jayaraman, 2010;Segura et al 2014;Tiwari et al, 2016, Dumka et al, 2018 but there is still limited work done on light-absorbing aerosol fractions in southern Africa (for example, Laakso et al, 2012;Vakkari et al, 2014;Feig et al, 2015;Maritz et al, 2015;Chiloane et al, 2017;Maritz, 2019).…”