Pattern classification of volatile organic compounds in various indoor environments

The purpose of this study was to survey the distribution patterns of volatile organic compounds (VOCs) and formaldehyde in the various indoor environments using cluster analysis. We investigated VOCs and formaldehyde in subway stations, underground shopping areas, medical centers, maternity recuperation centers, public childcare centers, large stores, funeral homes, and indoor parking lots from June 2005 to May 2006 (9 p.m. to 6 a.m.). The concentration of total volatile compounds (TVOCs) in maternity recuperations was 2,605.7 μg/m³, which was higher than that stated in the guideline and other chosen facilities. TVOCs in public childcare centers were 1,951.6 μg/m³, which also exceeded the guideline. Moreover, the concentration of TVOCs in every facility exceeded the guideline of the Ministry of Environment, Korea. In the case of formaldehyde, the mean concentration of 336.5 μg/m³ found only in public childcare centers exceeded the 120 μg/m³ stated in the guideline. Finally, by applying cluster analysis, three patterns of the indoor air pollutions were distinguished. In the results of the analysis, concentrations of TVOCs and formaldehyde of cluster 3 were higher than clusters 1 and 2, which were 2,561.4 and 184.9 μg/m ³, respectively.