This 1991 North Central Regional Extension publication explains that indoor air contains vast numbers of fine particles — such as smoke, dust, pollen, and bacteria — most of which are too small to be seen by the naked eye, with potentially over 400 million particles per cubic foot of air. It describes the size ranges of common indoor pollutants and the filtering devices used to capture them. Note: this document addresses residential indoor air quality and fine particle pollution, and does not contain information related to airport noise policy.Open full document
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This North Central Regional Extension publication explains the nature and sources of fine particle air pollution in residential settings, including smoke, dust, and pollen. It describes the size ranges of common indoor air pollutants and notes that most particles are too small to be seen by the naked eye, with potentially over 400 million unseen particles per cubic foot of indoor air. A chart illustrates the size ranges of various indoor air pollution particles and the control devices capable of capturing them.