Source profiles of particulate organic matters emitted from cereal straw burnings.
Cereal straw is one of the most abundant biomass burned in China but its contribution to fine particulates is not adequately understood. In this study, three main kinds of cereal straws were collected from five grain producing areas in China. Fine particulate matters (PM2.5) from the cereal straws subjected to control burnings, both under smoldering and flaming status, were sampled by using a custom made dilution chamber and sampling system in the laboratory. Element carbon (EC) and organic carbon (OC) was analyzed. 141 compounds of organic matters were measured by gas chromatography-mass spectrum (GC-MS). Source profiles of particulate organic matters emitted from cereal straw burnings were obtained. The results indicated that organic matters contribute a large fraction in fine particulate matters. Levoglucosan had the highest contributions with averagely 4.5% in mass of fine particulates and can be considered as the tracer of biomass burnings. Methyloxylated phenols from lignin degradation also had high concentrations in PM2.5, and contained approximately equal amounts of guaiacyl and syringyl compounds. beta-Sitostrol also made up relatively a large fraction of PM2.5 compared with the other sterols (0.18%-0.63% of the total fine particle mass). Normal alkanes, PAHs, fatty acids, as well as normal alkanols had relatively lower concentrations compared with the compounds mentioned above. Carbon preference index (CPI) of normal alkanes and alkanoic acids showed characteristics of biogenic fuel burnings. Burning status significantly influenced the formations of EC and PAHs. The differences between the emission profiles of straw and wood combustions were displayed by the fingerprint compounds, which may be used to identify the contributions between wood and straw burnings in source apportionment researches.
Zhang
Yuan-xun
YX
State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences, Peking University, Beijing 100871, China. zyx@plu.edu.cn
Shao
Min
M
Zhang
Yuan-hang
YH
Zeng
Li-min
LM
He
Ling-yan
LY
Zhu
Bin
B
Wei
Yong-jie
YJ
Zhu
Xian-lei
XL
D000383:Agriculture / Q000379:methods; D000393:Air Pollutants / Q000032:analysis*; D002241:Carbohydrates / Q000032:analysis; D002523:Edible Grain; D005227:Fatty Acids / Q000032:analysis; D006358:Hot Temperature; D009930:Organic Chemicals / Q000032:analysis; D010316:Particle Size; D012906:Smoke / Q000032:analysis*; D013261:Sterols / Q000032:analysis; D018505:Waste Management / Q000379:methods
D000393:Air Pollutants; D002241:Carbohydrates; D005227:Fatty Acids; D009930:Organic Chemicals; D012906:Smoke; D013261:Sterols