A Critical Review of the Impact of Retrofitting on Indoor Air Quality in Residential Buildings in Nigeria

The objective of this review paper is to critically examine the impact of residential building retrofitting on indoor air quality (IAQ). Indoor air quality plays an essential role in ensuring occupant health and comfort, yet it is often neglected in retrofitted residential buildings despite the increasing adoption of retrofitting as a strategy for improving energy efficiency. Retrofitted buildings can indirectly alter indoor environmental conditions through changes in building envelopes, ventilation rates, and material selection, which may influence pollutant accumulation and exposure levels. This review synthesizes existing literature on IAQ in retrofitted residential buildings, focusing on assessment approaches, pollutant metrics, climatic influences, and applicable standards. The review identifies key challenges, including the absence of localized IAQ standards, inadequate monitoring mechanisms, and limited theoretical and empirical studies within developing country contexts. Furthermore, the findings reveal gaps in regionally defined assessment methods and the limited adaptation of internationally established guidelines to local residential conditions. This review highlights the need for context-specific IAQ assessment frameworks and integrated retrofitting strategies that balance energy efficiency with indoor environmental quality. Future research should prioritize localized measurements and the development of adaptable IAQ guidelines to support healthier residential retrofit practices.