eng Science and Education Publishing Journal of Atmospheric Pollution 2381-2990 2017-05-13 5 1 24 32 10.12691/jap-5-1-4 JAP2017514 article Aniefiok E. Ite aniefiokite@yahoo.co.uk 1 2 Clement O. Ogunkunle 3 Clement O. Obadimu 3 Ekpedeme R. Asuaiko 4 Udo J. Ibok 4 Department of Chemistry, Akwa Ibom State University, P. M. B. 1017, Uyo, Akwa Ibom State, Nigeria Environmental Biology Unit, Department of Plant Biology, University of Ilorin, Nigeria Department of Geology, Akwa Ibom State University, P. M. B. 1017, Uyo, Akwa Ibom State, Nigeria 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 (PM1, PM2, PM5, PM10), temperature, relative humidity, carbon monoxide (CO) and carbon dioxide (CO2) levels were simultaneously measured in fourteen (14) sampling days using Fluke 985 Particle Counter and Fluke 975 AirMeter. The concentrations of particulate matter in the occupied air-conditioned office during the rainy season ranged from 5152 - 5984 μg/m3 for PM1; 2744- 3015 μg/m3 for PM2; 137- 149 μg/m3 for PM5 and 36- 50 μg/m3 for PM10 and in the unoccupied air̨Cconditioned office, the concentrations of particulate matter ranged from 1898 - 2556 μg/m3 for PM1; 987- 1311 μg/m3 for PM2; 38- 59 μg/m3 for PM5 and 15- 24 μg/m3 for PM10. During the dry season, the concentrations of particulate matter in the occupied air̨Cconditioned office ranged from 5852 - 6510 μg/m3 for PM1; 4490- 4992 μg/m3 for PM2; 335- 362 μg/m3 for PM5 and 59- 69 μg/m3 for PM10 and in the unoccupied air̨Cconditioned office, the concentrations of particulate matter ranged from 2598 - 3112 μg/m3 for PM1; 1168- 1694 μg/m3 for PM2; 153- 257 μg/m3 for PM5 and 29- 42 μg/m3 for PM10. This study has revealed that the particulate matter (PM1, PM2, PM5, PM10) concentrations in an occupied air̨Cconditioned 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 PM10 obtained in the present study were found to be much lower than the ambient maximum contaminant level for airborne PM10 standard promulgated by the United States Environmental Protection Agency (USEPA) (150 μg/m3 daily average and 50 ̦g/m3 annual average) and World Health Organization (WHO) PM10 guidelines values (50 ̦g/m3 daily average and 20 ̦g/m3 annual average). Although there were no significant relationships among PM1, PM2, PM5, and PM10 in occupied air-conditioned office, correlation analysis indicated that PM1, PM2 and PM5 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 air̨Cconditioned 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 CO2 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. http://pubs.sciepub.com/jap/5/1/4/jap-5-1-4.pdf indoor air quality particulate matter air-conditioned office staff exposure Akwa Ibom State University