Analysis of Volatile Organic Compounds in Indoor Air of Selected University Laboratories in North West Nigeria

University chemistry, biology, and engineering laboratories in North West Nigeria expose students, technicians, and researchers to complex mixtures of volatile organic compounds through solvent use, reagent preparation, and experimental procedures. Inadequate ventilation in many laboratory facilities compounds this exposure risk. This study systematically analysed volatile organic compound concentrations in the indoor air of twelve laboratories across three universities in Kano and Kaduna States, comparing organic air quality against occupational exposure limits and characterising differences between laboratory types and times of activity. Sampling was conducted using Tenax TA sorbent tubes during active and inactive periods, with thermal desorption-gas chromatography-mass spectrometry used for compound identification and quantification. Over sixty volatile organic compounds were detected across laboratories, including benzene, toluene, chloroform, hexane, acetone, diethyl ether, methanol, and various halogenated solvents. Benzene concentrations exceeded the UK WEL of 1 ppm in chemistry undergraduate teaching laboratories during active use periods in six of twelve sampled laboratories. Chloroform levels exceeded 2 ppm in two organic chemistry preparative laboratories. Total volatile organic compound concentrations during active use periods in organic chemistry labs reached 4,200 micrograms per cubic metre, substantially above the European guideline of 300 micrograms per cubic metre for indoor air. Inactive period concentrations remained elevated due to inadequate air exchange rates, with measurements confirming fewer than 0.5 air changes per hour in most facilities. The study fills a critical health risk assessment gap for Nigerian university laboratories and recommends comprehensive ventilation audits, fume hood performance testing, and solvent substitution programmes.

Keywords: volatile organic compounds, indoor air quality, university laboratories, occupational exposure, North West Nigeria