Wikipedia Article with references.
Plus: Indoor Air Pollution
Very informative US Government web page. Contains guides and many links to indoor air quality, indoor air pollution sources,
conditions, prevention, and much more information.
EPA: Indoor Air
Quality, types and sources of indoor air pollution
Environmental Protection Agency government web page. A book also is available in PDF format.
Air Ions and Human Comfort
Canadian Building Digest: Nature and effects of air ions, ion measurement and generation, ion
concentration in the atmosphere and in buildings, and other information and research.
Negative Ions Information Center
Information about negative ions, negative ion generators, ozone, allergy reports, and links
ENGINEERING - Penn State University
Information about negative ions, ozone, ultraviolet light, airborne pathogens
(microorganisms). A wealth of information, superbly done.
Informative page that discusses ion sizes, and very simply illustrates how
negative ions are formed (hold your mouse over the two moving atoms).
Bad Science - The Truth about oxygen
What about "Small Ions" ? From the Guardian Unlimited.