Particulate Matter and Staff Exposure in an Air-Conditioned Office in Akwa Ibom State University – Nigeria

Abstract

Indoor air quality parameters were investigated in an occupied air-conditioned office and unoccupied air-conditioned office located in the Faculty of Natural and Applied Sciences Complex in Akwa Ibom State University -Nigeria, during the rainy (June -July) and dry (November -December) seasons of 2016. Particulate matter (PM 1 , PM 2 , PM 5 , PM 10 ), temperature, relative humidity, carbon monoxide (CO) and carbon dioxide (CO 2 ) levels were simultaneously measured in fourteen (14) 10 . This study has revealed that the particulate matter (PM 1 , PM 2 , PM 5 , PM 10 ) concentrations in an occupied air-conditioned office were significantly (P < 0.001) higher than those obtained in unoccupied air-conditioned office during both rainy and dry seasons. However, the concentrations of PM 10 obtained in the present study were found to be much lower than the ambient maximum contaminant level for airborne PM 10 standard promulgated by the United States Environmental Protection Agency (USEPA) (150 μg/m 3 daily average and 50 μg/m 3 annual average) and World Health Organization (WHO) PM 10 guidelines values (50 μg/m 3 daily average and 20 μg/m 3 annual average). Although there were no significant relationships among PM 1 , PM 2 , PM 5 , and PM 10 in occupied air-conditioned office, correlation analysis indicated that PM 1 , PM 2 and PM 5 were significantly correlated at P < 0.01 in unoccupied air-conditioned office and correlation coefficients were different. Apart from suspended atmospheric dust and settling dust, human activities in the occupied air-conditioned office significantly influenced the particulate matter concentrations obtained compared to those obtained in unoccupied air-conditioned office in both rainy and dry seasons. Although the concentrations of CO and CO 2 were below detection limit (BDL), they indicated adequate air exchange at the time of the assessment in the air-conditioned office during the sampling period. The results obtained have revealed important contributions towards the understanding of particulate matter distribution patterns and provided baseline data that can be used for potential identification of human health risks associated with airborne particulate matter in air-conditioned offices in Akwa Ibom State University -Nigeria. Keywords