Evaluation of Volatile Organic Compounds at the Rooftop of the Chemical Use Laboratory Building in a University

Abstract

Objective : Volatile organic compounds (VOCs) are important air pollutants found in urban regions. VOCs cause adverse health effects to humans as well as being detrimental to the atmospheric environment. Various chemicals that produce VOCs are used in lab fume hoods, and are present in emissions of chemicals into the air through ventilation ducts. In Korea, it is not obligatory to install an air purifier in the ventilation system and thus, there is an inevitable contamination of the atmospheric environment. The purpose of this study was to assess the VOC concentrations on the rooftops of laboratory buildings in a university. Methods : A total of six buildings comprising four laboratory buildings and two non-laboratory buildings in a university campus were selected for the survey. VOCs were sampled using activated charcoal adsorbent tubes in front of the fume-hood exhaust located on the rooftops of the laboratory buildings and also on the rooftops of non-laboratory buildings. During the survey, factors such as meteorological conditions, the amount of chemicals being used, and air velocity at the exhaust, were considered. VOCs from samples were analyzed using gas chromatography with a flame ionization detector. One-way ANOVA, Pearson correlation, and multiple regression analyses were performed using SAS 9.2 to identify the factors affecting the VOC concentrations. Results : A total of 11 individual compounds were quantified in the samples collected at the study buildings. The concentrations of 10 VOCs at the laboratory buildings were significantly higher than those at the non-laboratory buildings (p < 0.01), with the exception of m, p-xylene (p = 0.155). The VOC concentrations were proportional to the chemical use in the laboratory building (p < 0.01). Using multiple regression analysis, we found that the amount of chemical use in each lab fume hood correlated to the concentrations of acetone (β = 0.650, p < 0.01), methylene chloride (β = 0.216, p < 0.01), n-hexane (β = 0.468, p < 0.05), and chloroform (β = 1.445, p < 0.01). The outdoor temperature was correlated to the concentrations of methylene chloride (β = 0.833, p = 0.103), n-hexane (β = 1.442, p < 0.05), and chloroform (β = 1.158, p < 0.05), and the relative humidity slightly affected methylene chloride (β = -0.390, p < 0.1) and chloroform (β = -3.762, p = 0.103) concentrations. Conclusion : The concentrations of VOCs from the laboratory fume hoods in the laboratory buildings were higher than the general atmospheric concentrations at the non-laboratory buildings on the campus. From this study, we suggest that the installation of an air purifier in the ventilation system of the school laboratory is necessary to create a green campus and to protect the atmospheric environment from pollutants that detrimentally affect outdoor air quality.