Sulfur Dioxide and Exercise: Relationships between Response and Absorption in Upper Airways

Free-radical chemistry of sulfite.

“…The S03 radical has been produced by oxidation sulfite with Ce4+ in acid solution (39)(40)(41), by reacti of sulfite with rad.icals produced by Fenton-type i agents, e.g., OH, NH2, and S4-(from the reaction Ti + with H202, NH2OH, S2082, respeetively) (42), reaction with radiolytically produced OH radicals other oxidizing radicals (43)(44)(45)(46)(47) OH + S02 -R OH-+ SOgby photoionization of sulfite directly (3,48,49) or throu photosensitizers (49) S032-+ hv -SO-+ eor by photolysis of dithionate (50) or thiosulfate (5 The S03-single-line ESR spectrum has been detect by using all ofthe above techniques (39)(40)(41)(42)46,47,49,5 as well as in biochemical systems such as horseradi peroxidase-hydrogen peroxide (52) or prostaglan( hydroperoxidase (53). Most of these studies report a g factor for S03 around 2.0030, except experimer with Ce4+ in acid solutions, where g = 2.0022 has be measured (39)(40)(41).…”

“…Sulfur dioxide can produce bronchoconstriction upon inhalation, particularly in asthmatics and during exercise (5,6). In addition to inhalation of SO2, sulfite can enter the body due to its use as a preservative in food, wine, and medications.…”

Effects of Inhaled Oxidant and Acidic Air Pollutant Combinations on Nasal and Tracheal Tissues in Exercising Rats

“…The nose is also an efficient scrubber of water soluble gases such as SO 2 and formaldehyde from inspired air. At the breathing frequencies and rates of minute ventilation typical of the exercising state the particle collection efficiency of the upper respiratory airways is increased; however, larger fractions of gaseous pollutants can penetrate deeper into the respiratory tract (YOKOYAMA and FRANK, 1972;KLEINMAN, 1984). It is likely that these generalisations apply to rats as well as humans.…”

Sulfur

“…When sulfur is inhaled as sulfur dioxide, it is rapidly absorbed both by the nasal mucosa and the upper respiratory tract (Kleinman 1984).…”