Characterisation of Volatile Organic Compounds in Indoor Air of Furniture Workshops in Lagos State and Associated Non-Cancer and Cancer Health Risk Assessment

Furniture workshops are significant indoor sources of volatile organic compounds from wood adhesives, varnishes, paints, and solvents, creating occupational exposure risks for craftsmen in Nigeria's large informal furniture manufacturing sector. This study characterises volatile organic compound profiles in indoor air of 30 furniture workshops in Ikeja and Surulere local government areas of Lagos State, South West Nigeria, and conducts non-cancer and cancer risk assessments for exposed workers. Indoor air sampling was performed using passive sorption tubes loaded with Tenax TA for a 48-hour sampling period. Thermal desorption and gas chromatography-mass spectrometry were used for identification and quantification. Target compounds include benzene, toluene, ethylbenzene, xylenes, formaldehyde, acetaldehyde, styrene, and naphthalene. Work duration, years of employment, and smoking status were obtained from questionnaires. Non-cancer hazard quotients and excess lifetime cancer risk were calculated using USEPA risk assessment methodology. Results show that benzene concentrations exceeded the WHO indoor air guideline of 1.7 micrograms per cubic metre in 87 percent of sampled workshops, with mean concentrations of 23.4 micrograms per cubic metre. Formaldehyde exceeded the NIOSH ceiling value in workshops using urea-formaldehyde adhesives. Cumulative excess lifetime cancer risk for long-term workers averaged 2.3 times 10 to the power of minus 4, exceeding the acceptable risk threshold of 10 to the power of minus 6. The study recommends mandatory ventilation standards for furniture workshops, substitution of benzene-containing solvents, and targeted occupational health surveillance programmes through the Lagos State Ministry of Labour. Keywords: volatile organic compounds, furniture workshops, indoor air, cancer risk, Lagos State