Use of a Nonnegative Constrained Principal Component Regression Chemical Mass Balance Model to Study the Contributions of Nearly Collinear Sources

Abstract

In this study, a nonnegative constrained principal component regression chemical mass balance (NCPCRCMB) model was used to solve the near collinearity problem among source profiles for source apportionment. The NCPCRCMB model added the principle component regression route into the CMB model iteration. The model was tested with the synthetic data sets, which involved contributions from eleven actual sources, with a serious near collinearity problem among them. The actual source profiles were randomly perturbed and then applied to create the synthetic receptor. The resulting synthetic receptor concentrations were also randomly perturbed to simulate measurement errors. The synthetic receptors were separately apportioned by CMB and NCPCRCMB model. The result showed that source contributions estimated by the NCPCRCMB model were much closer to the true values than those estimated by the CMB model. Next, five real ambient data sets from five cities in China were analyzed using the NCPCRCMB model to test the model practicability. Reasonable results were obtained in all cases. It is shown that the NCPCRCMB model has an advantage over the traditional CMB model when dealing with near collinearity problems in source apportionment studies.

Estimation of the direct and indirect impacts of fireworks on the physicochemical characteristics of atmospheric PM<sub>10</sub> and PM<sub>2.5</sub>

“…Based on our previous works and other related studies (Shi et al, 2009;Xue et al, 2010;Tian et al, 2013a;Zhao et al, 2013a, b), the PM 2.5 and PM 10 (24 h samples) were simultaneously collected on quartz-fibre filters and polypropylenefibre filters using medium-volume air samplers (TH-150) at a flow rate of 100 L min −1 . The detailed information for the sampling and quality assurance/quality control (QA/QC) are available in the Supplement.…”

“…Blanks and duplicate sample analyses were performed for nearly 10 % of the samples. The pretreatment procedure, chemical analysis and QA/QC are described in detail in the Supplement and refer to our previous works and other related studies (Bi et al, 2007;Shi et al, 2009;Wu et al, 2009;Kong et al, 2010;Xue et al, 2010;Zhao et al, 2013a, b).…”

Seasonal Study of Primary and Secondary Sources of Carbonaceous Species in PM10 from Five Northern Chinese Cities

“…The principle of CMB model had been described in lots of literature (Hopke, 2003;Shi et al, 2009). In this work, only the principle of CMB-Iteration model is presented, considering the length of the paper.…”

Comparison of Filtration System and a Honeycomb Denuder-Based System for Sampling PM2.5 in Tianjin, China

“…Enough blank tests (nearly 10% of samples) were conducted and used to correct corresponding data. The pre-treatment procedure, chemical analysis can be referred to our previous works and other related studies (Bi et al, 2007;Kong et al, 2010;Shi et al, 2009;Tian et al, 2014). Fig.…”

“…Therefore, confirming the optimum concentrations of coating solutions before sampling PM 2.5 using HDS is essential, especially in China where the atmospheric concentrations of particulate matter are much higher. Despite of the existence of sampling artifacts, samplers without denuders and back-up filters are still widely used because of the cost-effective equipment and convenient operation (Louie et al, 2005;Shi et al, 2009;Tian et al, 2014).…”