Martin L. Pall (PhD)
"It should be clear from the above, that chemicals acting in MCS are not acting on the classic olfactory receptors (15,16), but rather are acting as toxicants. This is opposite many published but undocumented claims that MCS is a response to odors. There is additional evidence arguing against the view that MCS is a reaction to odors. MCS sufferers who are acosmic, having no sense of smell, people who have intense nasal congestion and people whose nasal epithelia have been blocked off with nose clips can all be highly chemically sensitive (1,4). This does not necessarily mean that MCS never impacts the olfactory system. It simply means that MCS is not primarily an olfactory response. A recent study, confirmed this view, showing that the olfactory center in the brain in people with MCS was less sensitive to activation by chemical exposure than in normal controls, rather than being more sensitive (17)."