Formaldehyde is a common indoor pollutant with significant health implications. It is a colorless, flammable gas that is highly reactive and used in various industrial applications, including adhesives, resins, and coatings. Formaldehyde emissions come from both outdoor and indoor sources, with indoor sources including wood-based materials, flooring, insulation, and coatings. Outdoor sources include natural compounds, atmospheric reactions, combustion, and emissions from industrial processes. Formaldehyde is a known human carcinogen and can cause respiratory irritation, eye irritation, and other health effects. Formaldehyde is primarily released from wood-based products, especially those bonded with urea-formaldehyde resins. The use of formaldehyde in adhesives has decreased over time due to regulations and the development of alternative materials. However, formaldehyde emissions from these materials can still be significant, especially in new or renovated homes. Formaldehyde can also be produced through indoor combustion, such as from cigarettes, wood burning, and other sources. Sampling and analysis of formaldehyde in the indoor environment involve various methods, including in-situ techniques like spectroscopy, derivatization methods like the DNPH and acetylacetone methods, and sensors. These methods are used to measure formaldehyde concentrations in air, which are critical for assessing indoor air quality and health risks. Formaldehyde concentrations in indoor environments can vary widely, influenced by factors such as climate, building materials, and human activities. Guidelines for formaldehyde levels in indoor environments have been established by various countries and organizations, with limits set to protect public health. The reduction of indoor formaldehyde pollution is a key concern, with efforts focused on improving building materials, enhancing ventilation, and implementing stricter regulations. Future trends in formaldehyde analysis include the development of more sensitive and portable detection methods to better monitor and control formaldehyde levels in indoor environments.Formaldehyde is a common indoor pollutant with significant health implications. It is a colorless, flammable gas that is highly reactive and used in various industrial applications, including adhesives, resins, and coatings. Formaldehyde emissions come from both outdoor and indoor sources, with indoor sources including wood-based materials, flooring, insulation, and coatings. Outdoor sources include natural compounds, atmospheric reactions, combustion, and emissions from industrial processes. Formaldehyde is a known human carcinogen and can cause respiratory irritation, eye irritation, and other health effects. Formaldehyde is primarily released from wood-based products, especially those bonded with urea-formaldehyde resins. The use of formaldehyde in adhesives has decreased over time due to regulations and the development of alternative materials. However, formaldehyde emissions from these materials can still be significant, especially in new or renovated homes. Formaldehyde can also be produced through indoor combustion, such as from cigarettes, wood burning, and other sources. Sampling and analysis of formaldehyde in the indoor environment involve various methods, including in-situ techniques like spectroscopy, derivatization methods like the DNPH and acetylacetone methods, and sensors. These methods are used to measure formaldehyde concentrations in air, which are critical for assessing indoor air quality and health risks. Formaldehyde concentrations in indoor environments can vary widely, influenced by factors such as climate, building materials, and human activities. Guidelines for formaldehyde levels in indoor environments have been established by various countries and organizations, with limits set to protect public health. The reduction of indoor formaldehyde pollution is a key concern, with efforts focused on improving building materials, enhancing ventilation, and implementing stricter regulations. Future trends in formaldehyde analysis include the development of more sensitive and portable detection methods to better monitor and control formaldehyde levels in indoor environments.