Indoor Air Quality: Status and Standards
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Article Outline Glossary Definition Introduction Biological, Physical, and Chemical Sources of Pollution Deposition of Pollutants Ventilation Systems in Buildings In Situ Chemistry Indoor Air Quality and Health Remediation Methods Sustainable Buildings Future Directions Bibliography
Glossary Aerosol A suspension of particulate matter composed of solid and/or liquid material in a gas. Carbon Dioxide (CO2) CO2 is a part of the atmosphere (>405 ppm), and indoor concentrations in excess of ambient are mainly generated by people, about a kilogram per day depending on metabolism. The indoor exposure limit is commonly taken as 1000 ppm, a level at which the negative health effects of CO2 are not yet significant. CO2 is a useful Freja Hasager and Joachim Dithmer Bjerregaard contributed equally.
proxy for general indoor air quality including bioeffluents. Continued exposure to CO2 levels over 2500 ppm have been linked to drowsiness and tiredness. Studies have shown impacts on decision making and focus from around 1300 ppm [1]. Carbon Monoxide (CO) CO is a product of incomplete combustion. Indoor sources include heaters and stoves, tobacco smoke, and candles. CO is toxic to humans. Ambient air contains about 1 ppm of carbon monoxide. In busy streets, the atmospheric mole fraction can be in the range of 10–20 ppm. Indoor levels generally follow outdoor levels except in poorly ventilated houses with indoor CO sources [2]. Formaldehyde (CH2O) CH2O is a volatile organic compound that is found in indoor air due to off-gassing from building materials containing adhesives and polymers and objects like furniture and fabrics. It is also formed from the oxidation of hydrocarbons; in the indoor environment, this includes cigarettes and ozonolysis of aromatic hydrocarbons. Indoor concentrations depend on the age of the building and vary depending on season and time of day. CH2O is known to cause adverse health effects in humans. According to the World Health Organization’s guideline for formaldehyde, exposure should not exceed 0.1 mg/m3 (30-min average) [3]. Ventilation Systems Ventilation can be effectuated by mechanical or by natural means. In mechanical ventilation, fans are used to ventilate an enclosed space, while natural ventilation is dependent on the outside conditions and is driven by natural forces. Because modern buildings are becoming more well sealed (more impenetrable), ventilation or air exchange rates between indoor and outdoor air have decreased. This improves thermal efficiency, but contaminants from indoor sources will be trapped inside resulting in elevated pollutant concentrations that can cause adverse health effects in the occupants. It is now recognized that an optimal balance between
© Springer Science+Business Media, LLC, part of Springer Nature 2021 M. E. Goodsite et al. (eds.), Air Pollution Sources, Statistics and Health Effects, https://doi.org/10.1007/978-1-0716-0596-7_1097 Originally published in R. A. Meyers (ed.), Encyclopedia of Sustainability Science and Technology, © Springer Science+Business Media,
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