Impact of climate change on indoor air quality: emerging pollutants, health implications, and mitigation strategies

Abstract

Climate change has been recognised as an important factor affecting indoor environmental conditions including the indoor air quality (IAQ). Climate-related changes are mostly observed in the outdoor space, but many of their impacts are felt in the indoor space, as a result of the interactions between the outdoor climatic conditions, building features, ventilation systems, sources of indoor air pollution, and indoor activities. This review examines the possible impacts of climate change on IAQ, focusing on the changes in the nature and activity of IAQ pollutants. Major indoor air pollutants, such as particulate matter, gaseous pollutants and Volatile Organic Compounds (VOCs) are discussed in addition to emerging pollutants with growing concern, such as per- and polyfluoroalkyl substances (PFAS), bisphenols and organophosphate esters. The review additionally explores the potential impact of changes in temperature, relative humidity, precipitation patterns, ventilation circumstances, outdoor air pollution and extreme weather conditions on the generation, infiltration and persistence of indoor air pollutants. An increase in temperatures can increase emissions and volatilisation of some indoor chemicals, and changes in humidity can affect microbial growth, particle behaviour and chemical reactions. These interactions illustrate how climate change can alter the composition and concentration of pollutants in the indoor environment, which may increase occupants’ exposure to these pollutants and consequently elevate the risk of adverse health effects. High levels of particulate matter, VOCs, and other indoor air pollutants can cause respiratory and cardiovascular complications, allergic and inflammatory reactions, and, in some cases, neurological, developmental, and other health impacts. Children, older adults and people with pre-existing respiratory or cardiovascular diseases may be especially susceptible to these climate-related shifts in indoor exposures. These challenges can be addressed with more integration of climate adaptation, building design, ventilation management and indoor air-quality monitoring. The need for improved understanding of climate–building–pollutant interactions is then critical in designing resilient and healthy indoor environments in a changing climate.