Residential indoor air quality assessment in Ibadan metropolis, Nigeria

Abstract

Given the importance of the indoor air quality to healthy living, this study provides a situation analysis of residential indoor environments in Ibadan Metropolis. Data on building attributes and concentrations of inhalable particles (PM10) were obtained from 421 buildings, across high, medium and low-density residential areas with the aid of a structured questionnaire and MetOne-531S Particle Counter. Descriptive statistics were used to summarize collected data, while cooking fuel use index (CFUI) was computed using summative indexing on a five-point Likert response format. Findings revealed the preponderance of rooming building types (50.6%), side-hung windows (47.0%) and generators (51.8%). Ambient PM10 concentrations in residential areas revealed relatively low indoor air quality, with the low-density residential areas alone exhibiting a mean PM10 concentration (89.51 μg/m3) significantly lower than prescribed limit. Analysis of Variance (ANOVA) showed a significant difference in mean indoor PM10 for the different building types (F = 9.811, p = 0.0005) with rooming buildings having the highest concentration (429.23 μg/m3). Among residents, firewood (2.06), charcoal (3.10) and gas (3.61) exhibited the highest CFUI scores and there was a fairly weak but significant negative correlation (r = − 0.281; p = 0.0005) between cooking fuel efficiency and indoor PM10 levels. On the whole, inhalable particle pollution was higher in medium and high-density residential areas, varied with building types and driven by cooking fuels in the study area. A transition toward cleaner fuels and simple domestic preferences that could be revised were explicated upon as necessary measures to improve indoor air quality of residential dwellings in the city.