THS exposes people to mixtures of chemical compounds in gas phase and particulate phase similar to those contained in
mainstream smoke and SHS, as well as to additional products of surface reactions involving tobacco smoke constituents.
The particles of SHS tend to be smaller, and therefore stay airborne longer than
mainstream smoke.
This type of smoke contains more toxins and nicotine than
mainstream smoke.
328) Although noting that the "physiochemical nature" of ETS differed from that of
mainstream smoke, the Committee pointed out that ETS contained many of the same toxic chemicals as
mainstream smoke.
According to the American Lung Association, side-stream smoke contains more tar, nicotine and carbon monoxide than
mainstream smoke.
Research shows that more deleterious components are released into the environment with sidestream smoke than with
mainstream smoke.
Partly because ETS consists of the same carcinogenic chemicals found in
mainstream smoke (inhaled by the smoker), the report concludes that ETS can itself be classified by the EPA as a "Group A" carcinogen along with arsenic, asbestos, benzene and radon.
Mainstream smoke, filtered through the cigarette and inhaled by the smoker, is highly concentrated; the toxins it contains occur in comparatively large particles.
ETS contains many of the toxic agents and carcinogens that are present in
mainstream smoke, but in diluted form.
Mainstream smoke contains over 4000 identified substances, approximately 4 dozen of which are carcinogenic.
As expected, the
mainstream smoke -- the portion inhaled by the smoker -- collected from low-tar cigarettes induced 20 to 30 percent fewer mutations per mg of pollutants in the test system's growing bacteria than did
mainstream smoke from the high-tar brand.
Nonsmokers are also exposed to
mainstream smoke after the smoker exhales it.
