Indoor air quality risk assessment on the Canadian campus by a multilevel integrated weighted average method

Increasing incidents of indoor air quality(IAQ) related complaints lead us to the fact that IAQ has become a significant occupational health and environmental issue. However, how to effectively evaluate IAQ under different scale of multiple indicators is still a challenge. The traditional single-indicator method is subjected to uncertainties in assessing IAQ due to different subjectivity on good or bad quality and scalar differences of data set. In this study, a multilevel integrated weighted average IAQ method including initial walking through assessment(IWA) and two-layers weighted average method are developed and applied to evaluate IAQ of the laboratory building at the University of Regina in Canada. Some important chemical parameters related to IAQ in terms of volatile organic compounds(VOCs), methanol(HCHO), carbon dioxide(CO2), and carbon monoxide(CO) are evaluated based on 5 months continuous monitoring data. The new integrated assessment result can not only indicates the risk of an individual parameter, but also able to quantify the overall IAQ risk on the sampling site. Finally, some recommendations based on the result are proposed to address sustainable IAQ practices in the sampling area.

UNIFORM QUADRATIC CONVERGENCE OF A MONOTONE WEIGHTED AVERAGE METHOD FOR SEMILINEAR SINGULARLY PERTURBED PARABOLIC PROBLEMS＊

This paper deals with a monotone weighted average iterative method for solving semilinear singularly perturbed parabolic problems. Monotone sequences, based on the ac- celerated monotone iterative method, are constructed for a nonlinear difference scheme which approximates the semilinear parabolic problem. This monotone convergence leads to the existence-uniqueness theorem. An analysis of uniform convergence of the monotone weighted average iterative method to the solutions of the nonlinear difference scheme and continuous problem is given. Numerical experiments are presented.

Evaluation of regional water security using water poverty index

Water security is a widely concerned issue in the world nowadays.A new method,water poverty index(WPI),was applied to evaluate the regional water security.Twelve state farms in Heilongjiang Province,Northeastern China were selected to evaluate water security status based on the data of 2006 using WPI and mean deviation grading method.The method of WPI includes five key indices:resources(R),access(A),capacity(C),utilization(U)and environment(E).Each key index further consists of several sub-indices.According to the results of WPI,the grade of each farm was calculated by using the method of mean deviation grading.Thus,the radar images can be protracted of each farm.From the radar images,the conclusions can be drawn that the WPI values of Farm 853 and Hongqiling are under very safe status,while that of Farm Raohe is under safe status,those of Farms Youyi,597,852,291 and Jiangchuan are under moderate safe status,that of Farm Beixing is under low safe status and those of Farm Shuangyashan,Shuguang and Baoshan are under unsafe status.The results from this study can provide basic information for decision making on rational utilization of water resources and regulations for regional water safety guarantee system.