INDOOR AIR QUALITY AND MICROBIAL ASSESSMENT OF A NIGERIAN UNIVERSITY CAMPUS IN LAGOS, NIGERIA

Abstract

Good indoor air quality improves productivity at the workplace. On the other hand, poor indoor air quality could lead to losses in productivity as a result of comfort problems, ill health and sickness-absenteeism. The aim of the study was to assess indoor air quality in various rooms of university buildings covering the offices, lecture theatre, laboratory or workshops and public restroom across eight faculties in a conventional university. Investigations were conducted at twenty-nine indoor locations in the main campus of University of Lagos. Noise level, PM2.5, PM10, relative humidity and temperature, CO, SO2, NOx, and the microbial quality (fungal and bacterial) were all determined. The microbial quality was determined using the sedimentation method (open petri dishes) containing different culture media for sample collection. Noise level ranged from 61.60 to 84.10 dBA. The noise level is quite high in almost all sampling points especially in the workshops, yet there was no significant difference (P>0.05) across all the indoor sampling points and the WHO limit.SO2 were mostly absence, however, the highest value of 0.4 ppm was recorded which was higher than recommended limit of 0.1 ppm.PM2.5 ranged between 4.0–25.0 µg/m3 and PM10 were between 8.0–47.0 µg/m3. Though, there was high variation in PM2.5 and PM10 across all the indoor sampling points, there were no significant difference (P>0.05). They were below the maximum limit of 150 µg/m3.The total fungi load ranged from 10.4 to 963 CFU/m3. There was generally higher number of fungi in the restroom than all the other indoor environments and they were significant in Faculty of social sciences. Fungi isolates include Aspergillus spp. (86.2%), unidentified mold (13.77%) and Sporothrix schenckii (0.03%). Total bacteria load ranged from 96.3 to 689 CFU/m3. The lowest load of bacteria (9.63 x 101 CFU/m3) was recorded in the dean’s office at the faculty of environmental science. The rest rooms have higher bacterial load (6.89 x 102 CFU/m3), which was higher than the recommended maximum limit of 500 CFU/m3. Identification from the colonies showed that about 55% were gram negative and 45% were gram negative cells. Morphological studies showed that cocci were also more predominant over the bacillary shape bacteria (55% versus 45%).