## 1 Introduction  
One of the health risk factors, air pollution, has brought about approximately 3.7 million premature deaths in 2012, and is estimated to be affecting mostly on the mortality due to environmental effects by 2050 [1, 2]. PM\({}_{2.5}\), one of the air pollutants, is a particulate of aerodynamic diameter less than 2.5 \(\upmu\)m occupying 96% of those found in human lungs [3]. PM\({}_{2.5}\) penetrates the gas exchange region of the lungs and enters the circulatory system via passing through the respiratory barrier thereby spreads over the human body [4, 5, 6]. The Guidelines of Air Quality Management of World Health Organization recommend the employment of PM\({}_{2.5}\) instead of PM\({}_{10}\) as an indicator identifying air pollution; the public interest in the risk of PM\({}_{2.5}\) was increasing thereby [1]. To reduce the amount of PM\({}_{2.5}\), the sources of PM\({}_{2.5}\) in terms of the composition thereof needs to be identified. Depending on the sources of PM\({}_{2.5}\), the attribute of PM\({}_{2.5}\) can be distinguished into the artificial- and natural sources by which it can be divided into the primary matter directly discharged from sources and the secondary matter to be produced by chemical reaction of gas phase materials according to the photochemical reaction. The components of PM\({}_{2.5}\) consist mainly of carbons, such as organic mass (OM) including organic carbon (OC) and elemental carbon (EC), heavy metals and water soluble ions, etc. [7; 8; 9]. Less than 30% of organic compounds among the components can be identified as individual organic species wherein the part of materials of organic species exhibit very high source specificity [10]. These substances can be exploited as molecular markers to estimate the contribution of each source which are assigned in the model devised to identify sources of PM\({}_{2.5}\)[11; 12]. Representative molecular markers comprise levoglucosan (pyrolysis of biomass), hopanes and steranes (combustion of fossil fuels) and cholesterol (combustion of meats) [10; 12; 13]. In South Korea, although use of biomass materials, such as pine trees, as the fuel of boilers has been growing in rural areas, in which farmers use vinyl greenhouses to raise fruits, vegetables and tropical plants during winter. However, the major source of serious air pollution problems in rural and neighboring urban areas is the natural forest fire during wintertime in the dry condition. The other source of air pollution due to biomass burning is the open-burning of agricultural crop residues after harvest to prepare the next cultivation even though the government prohibited the burning activities. As discussed above, the chemical properties of organic aerosol particles from biomass burning emissions vary significantly depending on the burning phase and biomass type. It is still a major challenge to investigate the chemical properties. Distinguished sources of air pollutants can be employed as basic data for the reduction of emission of sources of air pollutants by which the contribution of air pollutants can be reduced. In general, diverse kinds of acceptance model techniques are used for the distribution of sources of air pollutants. Representative models for the distribution of sources of air pollutants comprise the principal component analysis (PCA), enrichment factors (EFs), chemical mass balance (CMB), positive matrix factorization (PMF), empirical orthogonal functions (EOF), multiple regression, Fourier transformation time series and other multivariate analysis, etc. [13; 14; 15; 16; 17; 18; 19; 20; 21; 22; 23]. Among them, the CMB model is most widely used to identify sources of PM\({}_{2.5}\)[24]. However, the CMB model accompanies uncertainties originated from errors for arbitrary measurements or errors of input variables (organic molecular markers) beyond analytic results and inputted molecular markers. Thus, component analysis of PM\({}_{2.5}\) and accuracy of input variables are needed for the CMB model [25].