LEAST TOXIC ACTIVATED CARBON MASK
A relatively non-toxic activated carbon mask that I use is a dual-cartridge half-mask respirator now sold under the "Survivair" brand name. It was previously made by Wilson. Many years ago I tried a dozen different brands, and the only ones that I found tolerable were one made by Wilson and one by Survivair. (Possibly since then other companies may have managed to reduce the toxicity of their masks.) Survivair has since bought out Wilson. Currently the less expensive model, the Survivair Value Air Plus, is the least toxic. Air it out for a week before using. For the replaceable cartridges, I use only the "Organic Vapor" type of activated carbon cartridge, even though they are not very good for removing formaldehyde, because I (and others with MCS) have found that cartridges with additives to remove additional compounds cause irritation. This mask will remove many of the irritating and odorous components of car and diesel exhaust, but note that there is no type of cartridge available that will remove carbon monoxide.
This mask and its cartridges are available from laboratory/safety supply companies, including Grainger. Below are listed the sizes available, with the manufacturer's model #, followed by Grainger's part # for each. The mask/respirator costs about $14.00, and a box of six (three pairs) of cartridges costs about $36.00.
small 3010 4RF41
med 3020 4RF42
large 3030 4RF43
Organic Vapor Cartridges (6) TO1 4EU73