Air Quality and Stationary Source Emission Control (1975) / Chapter Skim
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2 General Considerations
2 General Considerations
Pages 4-34
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From page 4... ...
; 1~ 131,fi:, AL GENERAL CONE ATWQSP~IC ==C=, T~TIONS A~ SI=S ·. An understanding of the sources, atmospheric reactions, and eventual sinks of sulfur oxides · and particles would be of enormous value in studying the health effects of these pollutants and devising~appropriate control strategies.
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From page 5... ...
is derived from fossil-fuel co~bus;tion :~ {Altshuller 1973~..:However, further refinement of the data is necessary. >The atmospheric residence times of the various sulfur oxides are not precisely known.
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From page 6... ...
-Rain plays- an important role in removing atmospheric Sulfur oxides, but the resulting increase in raindrop acidity is believed to have affected vegetation in-the United States and northern Europe adversely. Sulfur oxides returned-to the sa~-may be reduced to.
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From page 7... ...
sulfur trioxide,;.SO3 the a,nhydrous -form of sul.-.furic Lucia, HiSOt-''`Inasmuch asgaseous, sulfur,` t.r,ioxide reacts almost;' -> instantane...ously-~-i,th.water vapor to form :sulfuric acid aerosol :(reaction 1~) ~-'reacti.ons la and lb can be considered to be a single '' i ' reaction in whi$h,,sulfur dioxide is.;'oxidized'to sulfuric acid,..
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From page 8... ...
Earlier studies usually measured the sulfation rate of a lead peroxide candle over relatively long periods. This prOcedure is somewhat at the mercy of meteorologic conditions and may to some extent include other sulfur oxides.
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From page 9... ...
n is that the for~nati~on of sulfuric acid aerosol conceivably decreases sunlight and thereby lessens He rate at which further sulfuric acid is foneed. Ozone: itself c" also oxidize sulfur dioxide in the presence of water droplets, but this reaction occurs very ';lowi~ in the;gas phase- {box and Penkett 1972~.
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From page 10... ...
Two types of information are obviously necessary: the relative toxicities of the various airborne sulfur oxides, and the sources and atmospheric processes that result in their formation. These subjects are under study.
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From page 11... ...
The rather significant rural sulfate burden, despite minimal sulfur dioxide content, has been especially evident in the Northeast and has led the Environmental Protection Agency to suggest~that long-range transport of sulfur oxides produced by the relatively prevalent. fossil-fuel combustion in this area has produced a regional decrease in air quality.
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From page 12... ...
The role of the weakly basic ammonia in forming acid sulfates has been evaluated in a few controlled chamber studies; atmospheric ammonia in the parts-per-billion range may have a significant impact on the formation of acid sulfates (McKay 1971, Van Den Heuvel and Mason 1963~. Of utmost importance to sulfur oxide toxicity is the observation that the overwhelming majority of sulfate compounds derived from fossil fuels are in the submicrometer range and can therefore penetrate deeply into the respiratory tract.
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From page 13... ...
given ~ concentration of total suspended ~particles,there may be a wide range in the fraction- that is respirable or that is oft specific form,-: SUGAR as;:~ulfates or nitrates Accordingly, the total suspended particulate ~ or smoke shade Procedures result in only an indirect measurement of those particles in polluted air which are in furious. Fll~thennore-, the cation content of respirable parti~lates has generally nOt been measured,~nor have the potential health ef f eats of such cations been explored in detail .
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From page 14... ...
The dif f iculties in extrapolating animal data to man are derived to a large extent [£~ species differences. This is particularly true for pulmonary effects, in view of the relatively marked difference in respiratory tract anatomy and physiology between .
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From page 15... ...
Controlled Human-Exposure Experiments Controlled human-exposure studies in which volunteers ~ inhale defined concentrations of air pollutants, either singly or in mixtures, hate provided significant information concerning the effects of sulfur oxides. This approach allows determi-nation~of a doserespons-e.
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From page 16... ...
However, the evidence -indicates' that ne~lier-~£ these measurements directly reflects potential health effects, An that oxidation products of sulfur dioxide are probably more responsible for health effects than sulfur dioxide alone and because, of 0e total suspended particles, only the smaller ones- can penetrate into the respiratory tract.
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From page 17... ...
characteri^stics.of particles, so more.a.~curate dose data~should be forthcoming. However, the relative lack of such information in..the past hampers determination of the role of sulfuric acid and particulate sulfates in causing or ~ aggravating chronic respiratory disease, which presumably reflects the cumulative effects of inhalation of pollutants over a period of .
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From page 18... ...
Tn such situations, interpretation of the applicab~l~ty of the results can be difficult. For Instance, the finding that one particular response is statistically related to a partiOf confid9en°f ~pPOllutant at the 5 perce ~ ~ ~n-20 possibility that the result is due solely to chance -- would have questionable value in a study in which 20 sets of response-dose combinations were evaluated Another point should be noted on the subject of the relevance of epidemiologic studies of acute nonlethal responses in setting air quality standards: The question of what constitutes a disease effect and what can be considered a normal nonharmful response.
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From page 19... ...
It is also conceivable that repeated reversible adaptive changes over a period of many decades may lead inexorably to a chronic disease process. The resolution of this question must ultimately come f rom epidemiologic studies of the chronic effects of exposure to pollutants.
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From page 20... ...
It must be emphasized that careful epidemiologic studies can yield excellent information concerning the health effects of air pollutants. Such studies have clearly indicated a causal role of atmospheric sulfur oxides in human disease.
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From page 21... ...
The respiratory consequences of the i~halation of sulfur oxides and particles depend; greatly on which external orifices are infuse. The convoluted and mist nasal pasSageway:s are extremely efficient filters for highly solu}~legases, such as sulfur ~ dioxide, and for particles Vaughan et al.
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From page 22... ...
A propensity to breathe through the mouth would theref ore be expected to lead to an increased rish of pollutant effect in the respiratory tract. Among the causes of increased mouth breathing are exercise, emotional stress, and blockage of the nasal passageways, the latter usually occurring as a consequence of viral upper respiratory infection.
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From page 23... ...
However, there is no direct evidence of Ian effect Of sulfur oxides, in concentrations approaching ambient conditions, on mucociliary function in the lower respiratory tract.
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From page 24... ...
·! sT10 AL 1 1~ lam VARIATIONS IN REspo ma If the, goat, that ethnic men their populations in the n the white a United nd non States 'have been trite
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From page 25... ...
chronic respiratory disease mortality data also tends to support a greater susceptibility to pulmonary irritants among the white population. Although the male death rates for bronchitis and emphysema were t;imilar in whites and nonwhites 25 years ago, the recent steep increase in deaths from these disorders.
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From page 26... ...
A familial tendency toward chronic bronchitis has also been suggested, and inherited factors might be responsible for differences in the metabolism of pollutants and in the bronchoconstrictive response to inhaled irritants. ;` In addition to disease states and smoking, other, more subtle environmental factors might play ~ role in conditioning the response to sulfur oxides.
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From page 27... ...
~lity might —-en ~~hodologic ~ dews due to the llutants ~ believed pies are —En:' _~x series Ire, it berated in t acute gown people Wily, an gender a ~ : : pity to it, ~ al..
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From page 28... ...
dioxide and S(lf9a73) Atm°Spheric sulfur ~l ~_1 ~1 ~ I ~11 ~erosf1l974J | ~ hengclRnce 184 156_~58 e St.
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From page 29... ...
29 ~ Aid' ~ ";,'t -~ Me of - sulfur .. Dines in E:_~Lreh.
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From page 31... ...
P Review of the health effects of sulfur oxides.
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From page 32... ...
J Moll ~ 1 9 6 0J Formation of sulfuric acid in flogs.
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From page 33... ...
~ 973) A su ey of respiratory disease among New York y postal and transit workers.
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From page 34... ...
~: Sulfuric that is highl though its e has not been: pH, sulfur d1 of sulfite, S These ions at by a widely d Accordingly,mechanism Of.c its weak acid bisulfite ion The rece reflexes appe in hydrogen ~¢~ fore conceive sulfur dioxides flex bronchoc' decrease in p] "rations of t3 even more lid response, and; vate the same Relative button, metals and bisulfite>~ radioactively-¢have confirmed dioxide is aft the body (Yok 1960)
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