Biomass burning contribution to Beijing aerosol

Abstract

Biomass burning, the largest global source of elemental carbon (EC) and primary organic carbon (OC), is strongly associated with many subjects of great scientific concern, such as secondary organic aerosol and brown carbon which exert important effects on the environment and on climate in particular. This study investigated the relationships between levoglucosan and other biomass burning tracers (i.e., water soluble potassium and mannosan) based on both ambient samples collected in Beijing and source samples. Compared with North America and Europe, Beijing was characterized by high ambient levoglucosan concentrations and low winter to summer ratios of levoglucosan, indicating significant impact of biomass burning activities throughout the year in Beijing. Comparison of levoglucosan and water soluble potassium (K⁺) levels suggested that it was acceptable to use K⁺ as a biomass burning tracer during summer in Beijing, while the contribution of fireworks to K⁺ could be significant during winter. Moreover, the levoglucosan to K⁺ ratio was found to be lower during the typical summer period (0.21 ± 0.16) compared with the typical winter period (0.51 ± 0.15). Levoglucosan correlated strongly with mannosan (<i>R</i>² = 0.97) throughout the winter and the levoglucosan to mannosan ratio averaged 9.49 ± 1.63, whereas levoglucosan and mannosan exhibited relatively weak correlation (<i>R</i>² = 0.73) during the typical summer period when the levoglucosan to mannosan ratio averaged 12.65 ± 3.38. Results from positive matrix factorization (PMF) model analysis showed that about 50% of the OC and EC in Beijing were associated with biomass burning processes. In addition, a new source identification method was developed based on the comparison of the levoglucosan to K⁺ ratio and the levoglucosan to mannosan ratio among different types of biomass. Using this method, the major source of biomass burning aerosol in Beijing was suggested to be the combustion of crop residuals, while the contribution from softwood burning was also non-negligible, especially in winter

Estimation of the direct and indirect impacts of fireworks on the physicochemical characteristics of atmospheric PM&lt;sub&gt;10&lt;/sub&gt; and PM&lt;sub&gt;2.5&lt;/sub&gt;

“…In the present work, the sources to Cl − are complex, including not only anthropogenic but also natural sources (Vassura et al, 2014). Additionally, considering insufficient concentrations of Cr in the PM mass, K + and Mg 2+ may be more powerful as tracers of fireworks for the following source apportionment, as indicated by related reports Cheng et al, 2013).…”

“…Furthermore, it is interesting to find the relatively higher weighting of other species, such as OC, Al, Si and Ca. Strong links with K + and OC could demonstrate biomass combustion (Cheng et al, 2013). Factor 5 was also associated with Al, Si and Ca, which are crustal elements.…”

Observation of atmospheric peroxides during Wangdu Campaign 2014 at a rural site in the North China Plain

“…Nevertheless, in addition to the biomass burning, CO level in the NCP was also affected by anthropogenic activities with the regional transport of polluted air masses, for example, the urban plumes. It has been proved that airborne K + is acceptable as the tracer for biomass burning during summertime in the NCP (Cheng et al, 2013;Wang et al, 2015). The concentrations of CH 3 CN, another tracer for biomass burning, measured by Proton-transfer-reaction mass spectrometry (PTR-MS) exhibited similar temporal variation to the concentrations of K + during the Wangdu campaign 2014 except on 10 June (X.…”

“…Here, we tested the hypothesis by means of the box model and linear regression with the observation data from three events mentioned below during the Phase II. It is well known that CO and K + can be used as the reference for the biomass combustion Reid et al, 2005;Li et al, 2007;Sullivan et al, 2008;Cheng et al, 2013Cheng et al, , 2014J. F. Li et al, 2014;Wang et al, 2015).…”

Open burning of rice, corn and wheat straws: primary emissions, photochemical aging, and secondary organic aerosol formation

“…Open burning of agricultural residues, a convenient and inexpensive way to prepare for the next crop planting, could induce severe regional haze events (Cheng et al, 2013;Tariq et al, 2016). Among all the biomass burning types, agricultural residue burning in the field is estimated to contribute ∼ 10 % of the total mass burned globally (Andreae and Merlet, 2001), and its relative contribution is even larger in Asia (∼ 34 %), and especially in China (> 60 %) (Streets et al, 2003), where > 600 million people live in the countryside (NBSPRC, 2015).…”