Oral Presentation World Sustainable Built Environment Conference 2026

Investigating the relationship between airtightness, cooking fuel and indoor air quality in dwellings through in-situ CO2, NO2 and PM2.5 measurements (132908)

Muthukumar Maragathamayil 1 2 3 , Nicola Willand 1 2 3 , Lucy Gunn 2 3 4 , Nigel Goodman 1 3 5
  1. School of Property, Construction and Project Management, RMIT University, Melbourne, Victoria, Australia
  2. Centre for Urban Research, RMIT University, Melbourne, Victoria, Australia
  3. Healthy Environments and Lives (HEAL) National Research Network, Canberra, Australian Capital Territory, Australia
  4. School of Global, Urban and Social Studies, RMIT University, Melbourne, Victoria, Australia
  5. Heal Global Research Centre, Health Research Institute, University of Canberra, Canberra, Australian Capital Territory, Australia

Australians spend most time indoors where their health may be impacted by indoor air quality (IAQ). Factors including dwelling airtightness, heating and cooking appliance type (fuel), outdoor and indoor conditions, occupant behaviour and climate change can influence IAQ in dwellings. However, there is a lack of research in the Australian context investigating relationships between these factors and IAQ in dwellings. This study aimed to address this gap using a quantitative approach with low-cost sensors in four households in inner west Melbourne, Australia, which experiences high outdoor pollution levels. Purposive sampling presented four households with diverse heating and cooking appliance types (gas or electric) and high/low draughtproofing status. Air quality monitors measured indoor and outdoor levels of carbon dioxide (CO2), fine particulate matter (PM2.5) and nitrogen dioxide (NO2) at 5-minute intervals in the main living room and bedroom for one week in summer (February 2025) and winter (June–July 2025). Dwelling airtightness was evaluated by calculating the air change rate (ACR) using CO2 measurements in the bedroom as a tracer gas (decay method). Ordinary least squares regression analysis with a heteroscedasticity and autocorrelation consistent estimator tested the relationship between airtightness, cooking fuel and IAQ in dwellings. Winter results showed that the leakiest house (0.24<ACR<0.32, doors closed) was associated with higher indoor PM2.5 concentrations (0.305<coefficient<0.316, p<0.001) than in other dwellings (0.081<ACR<0.150, 0.142<coefficient<0.247, p<0.001) possibly due to penetration of outdoor PM2.5 concentrations. Furthermore, gas cooking was associated with higher indoor NO2 concentrations in the kitchen/living areas (coefficient=0.850, p<0.001)(coefficient=0.638, p<0.05) when compared to electric cooking in households with similar outdoor NO2 pollution levels. The findings could help householders, designers, builders and policy makers understand the relationship between dwelling airtightness and type of cooking appliance on indoor PM2.5 and NO2 concentrations which could influence modifications to existing dwellings and the design of new dwellings.