Waste container weighing data processing to create reliable information of household waste generation.

Household mixed waste container weighing data was processed by knowledge discovery and data mining techniques to create reliable information of household waste generation. The final data set included 27,865 weight measurements covering the whole year 2013 and it was selected from a database of Helsinki Region Environmental Services Authority, Finland. The data set contains mixed household waste arising in 6m(3) containers and it was processed identifying missing values and inconsistently low and high values as errors. The share of missing values and errors in the data set was 0.6%. This provides evidence that the waste weighing data gives reliable information of mixed waste generation at collection point level. Characteristic of mixed household waste arising at the waste collection point level is a wide variation between pickups. The seasonal variation pattern as a result of collective similarities in behaviour of households was clearly detected by smoothed medians of waste weight time series. The evaluation of the collection time series against the defined distribution range of pickup weights on the waste collection point level shows that 65% of the pickups were from collection points with optimally dimensioned container capacity and the collection points with over- and under-dimensioned container capacities were noted in 9.5% and 3.4% of all pickups, respectively. Occasional extra waste in containers occurred in 21.2% of the pickups indicating the irregular behaviour of individual households. The results of this analysis show that processing waste weighing data using knowledge discovery and data mining techniques provides trustworthy information of household waste generation and its variations.

Prevalence of building-related symptoms as an indicator of health and productivity.

BACKGROUND: The prevalence of building-related symptoms (BRS) is commonly used to characterize the indoor air quality in office buildings. To analyze the costs of building renovation and the improvement of the indoor environment, it is useful to quantitatively relate the prevalence or intensity of BRS to productivity. The intent of this study is to summarize the links between the BRS and productivity, and demonstrate this linkage in two case buildings. MATERIAL AND METHODS: A literature was surveyed for studies that measured simultaneously the prevalence or intensity of BRS and subjectively reported or objectively measured productivity. Case studies in two office environments were performed. An association between the prevalence of BRS and productivity of workers in a call center and in an insurance office were investigated. In the first case study, the productivity was expressed using the direct productivity metrics, namely the number of telephone contacts during active working hours while in the second case, the productivity was assessed by using the data concerning sick leave rates. RESULTS: Employees who report more BRS also have more often absences which relate to indoor environment quality (IEQ). Their productivity is lower than those who have better IEQ in their offices. Despite uncertainties related to the data concerning recorded sick leave and self-reported productivity, the number of studies showing an association between BRS and productivity or sick leave suggests that such a relationship exists. The present case studies also demonstrated an association between the BRS and the direct productivity. Based on the data from the call center, a reduction of 10%-units in the prevalence of general symptoms (such as fatigue, headache, nausea, etc.) corresponded with a gain of 1.5% in performance. Based on the findings in the insurance company, a reduction of 10%-units in the prevalence of irritation symptoms corresponded with a decrease of 0.7% in the short-term absenteeism. CONCLUSIONS: A review of 23 studies suggests that a linkage exists between typical BRS and productivity indicators such as task or work performance or absence from work. Quantitative associations between BRS and productivity were demonstrated in two office environments. Quantitative associations between BRS and economic metrics enable cost-benefits analysis.