Indoor air quality (IAQ) describes the air quality in buildings and rooms. Despite the well-known outdoor exposures to gases such as ozone and pesticides, indoor air can be even more problematic in terms of pollution. Substances such as formaldehyde, volatile organic compounds (VOCs) or CO₂ are emitted by construction materials, furniture, and humans. This pollution, while sometimes not actively perceived, affects ones well-being, the cognitive performance and increases the risk for diseases such as lung cancer or stroke. Thus, monitoring and sustaining a high IAQ is important for overall well-being and health.