Sulfur dioxide health effects

Sulfur dioxide Fuel combustion (coal, oil), smelting and casting, manufacture of paper by sulfite process Primary metals (ferrous and nonferrous) pulp and paper Sensory and respiratory irritation, vegetation damage, corrosion, possible adverse effect on health... 

A difficulty that should not be overlooked is that airborne particulates are rarely homogeneous. They vary greatly in size and shape, and their chemical composition is determined by factors specific to the source and location of the emissions. The combined effects and interactions of various substances mixed with particulates have not yet been established (except for sulfur dioxide), but they are believed to be significant, especially where long-term exposure occurs. Measurement techniques and their reliability may vary across regions and countries, and so may other factors, such as diet, lifestyle, and physical fitness, that influence the human health effects of exposure to particulates. 

Health effects attributed to sulfur oxides are likely due to exposure to sulfur dioxide, sulfate aerosols, and sulfur dioxide adsorbed onto particulate matter. Alone, sulfur dioxide will dissolve in the watery fluids of the upper respiratory system and be absorbed into the bloodstream. Sulfur dioxide reacts with other substances in the atmosphere to form sulfate aerosols. Since most sulfate aerosols are part of PMj 5, they may have an important role in the health impacts associated with fine particulates. However, sulfate aerosols can be transported long distances through the atmosphere before deposition actually occurs. Average sulfate aerosol concentrations are about 40% of average fine particulate levels in regions where fuels with high sulfur content are commonly used. Sulfur dioxide adsorbed on particles can be carried deep into the pulmonary system. Therefore, reducing concentrations of particulate matter may also reduce the health impacts of sulfur dioxide. Acid aerosols affect respiratory and sensory functions. 

TABLE 8.6.3 Predicted Effects on Human Health of Exposure to Various Concentrations of Sulfur Dioxide ... 

Spiegelman, J. R., G. D. Hanson, A. Lazarus, R. J. Bennett, M. Lippmann, and R. A. Albert. Effect of acute sulfur dioxide exposure on bronchial clearance in the donkey. Arch. Environ. Health 17 321-326, 1968. 

Snell, R. E., and P. C. Luchsinger. Effects of sulfur dioxide on expiratory flow rates and total respiratory resistance in normal human subjects. Arch. Environ. Health 18 693-698, 1969. 

Most of the information on the effects of air pollution on humans comes from acute pollution episodes such as the ones in Donora and London. Illnesses may result from chemical irritation of the respiratory tract, with certain sensitive subpopulations being more affected (1) very young children, whose respiratory and circulatory systems are poorly developed, (2) the elderly, whose cardiorespiratory systems function poorly, and (3) people with cardiorespiratory diseases such as asthma, emphysema, and heart disease. Heavy smokers are also affected more adversely by air pollutants. In most cases the health problems are attributed to the combined action of particulates and sulfur dioxides (SO2) no one pollutant appears to be responsible. Table 4.2 summarizes some of the major air pollutants and their sources and effects. 

Sulfur dioxide. The sources are burning coal and oil, especially high sulfur coal from Eastern US, and industrial processes (paper and metal industry). Health effects include breathing problems, which may cause permanent damage to lungs. Environmental effects are as follows S02 is an ingredient of acid rain (acid aerosols), which can damage trees and life in lakes. Acid aerosols can also reduce visibility. 

Several epidemiologic studies have examined the health effects of inhalation exposure to sulfur compounds (e.g., Jaakkola et al. 1990 Marttila et al. 1995 Partti-Pellinen et al. 1996 other studies summarized in ATSDR 1999). The first three studies are part of the South Karelia air pollution study (Table 7-2). In general, the studies report that exposure to sulfur dioxide and other sulfur com... 

This chapter reviews the physical and chemical properties and toxicokinetic, toxicologic, and epidemiologic data on sulfur dioxide. The Subcommittee on Submarine Escape Action Levels used this information to assess the health risk to Navy personnel aboard a disabled submarine and to evaluate the submarine escape action levels (SEALs) proposed to avert serious health effects and substantial degradation in crew performance from short-term exposures (up to 10 d). The subcommittee also identifies data gaps and recommends research relevant for determining the health risk attributable to exposure to sulfur dioxide. 

Many studies have examined the human health effects from exposure to sulfur dioxide. The next section examines the effects of experimental, accidental, occupational, and community exposures however, more complete reviews are available in the Toxicological Profile for Sulfur Dioxide (ATSDR 1998) Air Quality Criteria for Particulate Matter and Sulfur Oxides (EPA 1982) and Supplement to the Second Addendum (1986) to Air Quality Criteria for Particulate Matter and Sulfur Oxides (1982) (EPA 1994a,b). 

Table 9-2 summarizes exposure studies that used controlled exposures to sulfur dioxide. Mild irritation, bronchoconstriction, and decreased lung function, as assessed by measurements of specific airway resistance or decreases in forced expiratory volume or expiratory flow, are produced after exposure of healthy individuals to low concentrations of sulfur dioxide. People with asthma are more susceptible. Exercise, cold air, and airborne participates appear to exacerbate the toxic effects (Gong et al. 1995 Roger et al. 1985 Schachter et al. 1984 Stacy et al. 1981). Concentration seems to be more important than duration as a determinant of health effects. Initial atmospheric exposure to sulfur dioxide can result in immediate discomfort, irritation, and coughing that abate after gradual acclimation to increasing concentrations (Andersen et al. 1974). Health effects reported by healthy volunteers are summarized in Table 9-3. 

Acute inhalation exposure to sulfur dioxide produces lethal and nonlethal effects in laboratory animals. Data suggest that the sensitivity of animals to sulfur dioxide varies Rats are most resistant and guinea pigs are most sensitive. Table 9—4 lists the concentrations that produce 50% mortality in exposed animals (LC50). Acute lethality at exposures greater than 100 ppm appears to be a function of concentration and duration of exposure. For example, LC50s were calculated in mice exposed to nominal concentrations of 150, 1,000, and 3,000 ppm sulfur dioxide for exposure durations of 847 h, 4 h, and 30 min, respectively (Hilado and Machado 1977 U.S. Department of Health Education and Welfare 1969, as cited in ACGIH 1994). 

On the basis of its review of human and experimental animal health-effects and related data, the subcommittee concludes that the Navy s proposed SEAL 1 of 3 ppm for sulfur dioxide is too conservative. The subcommittee recommends a SEAL 1 of 20 ppm. The subcommittee s recommendation is supported by several occupational studies that show tolerance to irritant effects from repeated exposures at 20 ppm (Ferris et al. 1967 Kehoe et al. 1932 Skalpe 1964). It is also supported by a study in which volunteers showed tolerance to a 6-h exposure at 25 ppm (Andersen et al. 1974) and minimal pulmonary flow resistance to a 10-min nose-only exposure at 15 or 29 ppm (Frank 1964). Effects on mucus flow and airflow resistance are to be expected at exposure concentrations of 20 ppm (Frank et al. 1964), however, they should not impair the submariners ability to escape. Healthy submariners should be able to tolerate irritative effects associated with exposures to less than 20 ppm for up to 10 d. 

Baskurt, O.K. 1988. Acute hematologic and hemorheologic effects of sulfur dioxide inhalation. Arch. Environ. Health 43(5) 344-348. 

Goldring, I.P., L.Greenburg, S.S.Park, and I.M.Ratner. 1970. Pulmonary effects of sulfur dioxide exposure in the Syrian hamster. II. Combined with emphysema. Arch. Environ. Health 21... 

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