An analysis by the Observatoire de la Qualité des Environnements Intérieurs (OQEI) on September 29, 2026, examined the health and economic impacts of indoor air pollution in French homes. The study used the most recent data available to look at how indoor air quality affected the health of the entire population in mainland France between 2020 and 2023. It found that improvements in indoor air quality over the past 20 years have helped prevent numerous illnesses and saved significant amounts of money. The researchers suggested that even more health and economic benefits could be achieved by reducing sources of pollution, especially fine particles (PM2.5), passive smoking, and the presence of humidity and mold. Since the early 2000s, the levels of several harmful pollutants in indoor air have dropped significantly. These include toluene, formaldehyde, benzene, and fine particles (PM2.5). This improvement has helped prevent several tens to hundreds of thousands of people from developing asthma. The study's authors credited these changes to stricter regulations, improvements in housing, reductions in certain pollution sources, the use of safer materials, and the requirement to label construction products with information about their potential health effects. Despite these improvements, the study found that 75% of homes in France still have indoor air quality that exceeds the guideline for fine particles. If all homes met the recommended air quality standards, the study estimates that 47,900 new cases of hypertension in adults, 24,150 cases of asthma in children, and 14,400 cases of chronic obstructive pulmonary disease (COPD) in adults could be avoided. These numbers highlight the ongoing importance of maintaining good indoor air quality for public health. At the individual level, simple steps can improve indoor air quality. These include ventilating homes for 10 to 15 minutes a day, even during winter, avoiding smoking or vaping indoors, limiting the use of candles, incense, and scented sprays, using household products according to their instructions, and regularly maintaining ventilation systems. These actions can help reduce exposure to harmful pollutants and promote better health.