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Effects of atmospheric pollution on human health
J. Aerosol Sci., vol. 21, Suppl. i, pp. S389-$396, 1 9 9 0 . Printed in Great Britain.
0021-8502/90 $3.00 + 0.00 Pergamon Press plc
E F F E C T S OF A T M O S P H E R I C P O L L U T I O N ON H U M A N H E A L T H
H.U. W a n n e r
D e p a r t m e n t of H y g i e n e and A p p l i e d Physiology, Federal I n s t i t u t e of Technology, ETH-Zentrum, CH 8092 Z u r i c h
ABSTRACT
M o s t air p o l l u t a n t s do not lead to s p e c i f i c diseases. D e p e n d i n g on the pollutant, the c o n c e n t r a t i o n and the d u r a t i o n of e x p o s u r e some organs are m o r e a f f e c t e d t h a n others. The m o s t frequent d i s o r d e r s are t h o s e c a u s e d by i r r i t a n t g a s e s and p a r t i c u l a t e s on the m u c o u s m e m b r a n e s and r e s p i r a t o r y organs. The c o n s e q u e n c e s are eye, nose and t h r o a t inflammations, dimin i s h e d lung function, i n c r e a s e d s u s c e p t a b i l i t y to r e s p i r a t o r y i n f e c t i o n and a h i g h e r i n c i d e n c e of c h r o n i c bronchitis. T h e s e d i s o r d e r s and d i s e a s e s are, of course, i n f l u e n c e d by o t h e r factors as well, such as immune deficiency, allergies, o c c u p a t i o n a l e x p o s u r e to pollutants, and p a r t i c u l a r l y smoking. The e f f e c t s of air p o l l u t a n t s are, therefore, m u l t i f a c t o r i a l l y c o n d i t i o n e d and n o n s p e c i f i c d i s o r d e r s are p l a c e d in the foreground. Evid e n c e for an a s s o c i a t i o n of air p o l l u t i o n w i t h a d v e r s e effects on h u m a n h e a l t h is d r a w n from three sources: animal experiments, e x p e r i m e n t a l human exposures, and e p i d e m i o l o g i c studies of e x p o s e d h u m a n populations. The b u r d e n of a t m o s p h e r i c p o l l u t i o n m u s t be r e d u c e d to p r o t e c t h u m a n h e a l t h by an a d e q u a t e s a f e t y margin. In particular, the i n c r e a s e d s e n s i t i v i t y of sick and aged p e o p l e as well as c h i l d r e n should be t a k e n into account. In d e f i n i n g the m a x i m u m i m m i s s i o n levels, p r e v e n t i v e a s p e c t s s h o u l d h a v e p r i o r i t y so as to k e e p the r i s k of d a m a g e to h e a l t h and the h a r m f u l influences on the e n v i r o n m e n t to a minimum.
KEYWORDS
Air p o l l u t a n t s ; h e a l t h effects; studies; air q u a l i t y standards.
epidemiological
studies;
experimental
M E T H O D S FOR P R O V I N G H E A L T H EFFECTS
T o d a y we h a v e r e l e v a n t s c i e n t i f i c m e t h o d s by w h i c h the i n f l u e n c e of div e r s e factors can be i n v e s t i g a t e d and considered. W i t h t h e s e we can m a k e s t a t e m e n t s a b o u t the e f f e c t s of air p o l l u t i o n on h u m a n b e i n g s and the environment. For a c o m p r e h e n s i v e evaluation, however, m u l t i p l e i n v e s t i g a tions u s i n g d i f f e r e n t types of field e q u i p m e n t and p o s i n g d i f f e r e n t types of q u e s t i o n s are a l w a y s necessary. The two m o s t i m p o r t a n t study m e t h o d s for p r o v i n g the e f f e c t s of air p o l l u t i o n on h e a l t h are e p i d e m i o l o a i c a l inv e s t i q a t i o n s and e x p e r i m e n t a l studies (Van E i m e r e n and Horisberger, 1987).
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E p i d e m i o l o g i c a l studies are i n v e s t i g a t i o n s for e s t a b l i s h i n g the effects of the actual air p o l l u t i o n load on a p a r t i c u l a r p o p u l a t i o n group. We differentiate b e t w e e n " c r o s s - s e c t i o n a l studies", in w h i c h the f r e q u e n c y of part i c u l a r h e a l t h p r o b l e m s in areas with d i f f e r e n t air p o l l u t i o n levels are compared, and " l o n a i t u d i n a l studies" w h e r e c o m p a r a t i v e o b s e r v a t i o n s are made of the same p o p u l a t i o n groups while u n d e r e x p o s u r e to lower and h i g h e r air p o l l u t i o n levels. (For example before, d u r i n g and after smog episodes). The m e a n i n g f u l n e s s of such studies d e p e n d s on the size of the i n v e s t i g a t e d group, the size of the sought or o b s e r v e d d i f f e r e n c e concerning h e a l t h effects, and the level of pollution. The d i s t r i b u t i o n in relation to age, sex, general health and social status m u s t be c o m p a r a b l e betw e e n the i n v e s t i g a t e d groups. Furthermore, we m u s t take into account the influence of i n t e r v e n i n g factors such as smoking habits, o c c u p a t i o n a l exposure and climate.
E x P e r i m e n t a l studies e s t a b l i s h the effects of individual p o l l u t a n t s or m i x t u r e s of p o l l u t a n t s d e p e n d i n g on the dosage, time of exposure, the physical activity, t e m p e r a t u r e and the air humidity. These studies are c o n d u c t e d w i t h v o l u n t a r y subjects by s t a n d a r d i z e d m e t h o d s and u n d e r p r e c i s e l y c o n t r o l l e d conditions. The results are v a l i d for the investigated group u n d e r the c o n t r o l l e d e x p e r i m e n t a l conditions. T h e y have only limited g e n e r a l i t y to c o n d i t i o n s in the real e n v i r o n m e n t w h e r e there are d i f f e r e n t m i x t u r e s of p o l l u t a n t s and c h a n g i n g c l i m a t i c conditions.
The f o l l o w i n g results of i n v e s t i g a t i o n s have shown a c o r r e l a t i o n b e t w e e n the f r e q u e n c y of chronic r e s p i r a t o r y d i s e a s e s and r e s p i r a t o r y symptoms in h e a l t h y p e r s o n s (adults and children) w i t h the e x t e n t of air p o l l u t i o n over e x t e n d e d periods of time.
E x a m p l e s of "cross sectional studies" Chapman et al. (1985) m a d e c r o s s - s e c t i o n a l i n v e s t i g a t i o n s in four cities which had d i f f e r e n t levels of p o l l u t i o n in Utah, in the USA. They interv i e w e d in total 5623 m o t h e r s and fathers of school children. T h e y established the l o n g - t e r m effect of r e l a t i v e l y low c o n c e n t r a t i o n s of sulphur dioxide on the f r e q u e n c y of chronic coughs and expectoration. In the most h e a v i l y e x p o s e d city (Magna) the average 5-year v a l u e s of s u l p h u r dioxide c o n c e n t r a t i o n s w e r e 115 m i c r o g r a m s per cubic m e t e r and of s u l f a t e s 14 micrograms per cubic meter. In the other cities the r e s p e c t i v e v a l u e s lay b e t w e e n ii and 36, r e s p e c t i v e l y 5 and 8 m i c r o g r a m s per cubic meter. The p r e v a l e n c e of c h r o n i c coughs and e x p e c t o r a t i o n in M a g n a for the non-smoking m o t h e r s was 4.2% and for the n o n - s m o k i n g fathers 7.8% on average. For the s m o k i n g m o t h e r s the p r e v a l e n c e was 21.8% and for the s m o k i n g fathers 22.2% on average. In the other cities the r e s p e c t i v e p r e v a l e n c e s were s i g n i f i c a n t l y lower, on average 2% or 17% respectively. No s i g n i f i c a n t d i f f e r e n c e was found b e t w e e n the cities with low p o l l u t i o n levels. M o s t a r d i et al. (1981) i n v e s t i g a t e d lung function v a l u e s and the frequency of r e s p i r a t o r y s y m p t o m s among 146 c h i l d r e n in the age g r o u p i0 to ii in an area w i t h h e a v y p o l l u t i o n and also 153 c h i l d r e n in the same age group in an area of low pollution. The frequency of r e s p i r a t o r y s y m p t o m s (coughing, runny noses, hoarseness, colds, irritation of the eyes) was e s t a b l i s h e d by a q u e s t i o n n a i r e filled in by the parents. Lung functions w e r e m e a s u r e d by means of a s p i r o m e t e r at school. At the school w i t h the h i g h e r p o l l u t i o n load the m e a n daily values during the school year for s u l p h u r dioxide were 77 and for n i t r o g e n d i o x i d e 54 m i c r o g r a m s per cubic meter. Individual symptoms per day w e r e about twice as frequent than in the school with less
Effects of atmospheric pollution on human health
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pollution (sulphur dioxide 21 and nitrogen dioxide 37 micrograms per cubic meter). Furthermore the lung function values during acute respiratory tract infections showed a larger degree of disorder. Braun et al. (1989) investigated the association between air pollutionand respiratory symptoms in a diary study on a random sample of 1063 Swiss children aged from 0 to 5 years in four different areas of switzerland (two urban, a suburban and a rural area). Passive samplers inside and outside the home measured nitrogen dioxide concentration over 6 weeks. During this time diaries were filled out by parents. 20% of them were validated with the attending pediatrician's case notes and were in good agreement. The frequency of respiratory symptoms per child per day was found to increase with increasing levels of nitrogen dioxide measured outdoors. The relationship was more significant for the non smoking families with Swiss children. Possible other factors were accounted for by multiple regression analysis; the variables "season" and "child's susceptibility to colds" also showed a significant association with respiratory symptoms. But the relationship between nitrogen dioxide outdoors and respiratory symptoms per child per day remained statistically significant. The result indicates that air pollution is a contributory factor in the development of respiratory symptoms in children. Euler et al. (1987, 1988) investigated the effect on the frequency of chronic obstructive airways disease from long term exposure to airborne dust pollution and sulphur dioxide, using a questionnaire from the National Heart, Lung and Blood Institute. Their subjects were a group of healthy adults. The relative risk, 1.18, under a concentration of sulphur dioxide of more than 105 micrograms per cubic meter over 500 hours per year, was significantly increased. With a concentration of airborne dust particles of more than 150 micrograms per cubic meter (2500 hours per year) a relative risk of 1.32 was also found. The same test group was exposed to oxidants at a concentration of more than 200 micrograms per cubic meter over 750 hours per year and the relative risk for chronic respiratory diseases (1.20) was higher than over an exposure time of 250 hours per year (1.07). With a concentration of more than 300 micrograms per cubic meter the relative risk increased with the time of exposure. Exposure to nitrogen dioxide did not show a significant correlation whereby only a small part of the population group under investigation was exposed to values over i00 micrograms per cubic meter. Passive smoking at work increased the prevalence of bronchitis significantly.
Example of a "lonqitudinal
study"
Wichmann et al. (1988) made measurements of lung function during smog periods in 1981 using different population groups, iii healthy workers from the areas of Cologne and Dusseldorf who were not occupationally exposed, showed increased airway resistance during the smog period in comparison to the control period. Additionally 59 patients with slight obstructive airway disease who came from diverse regions of Germany showed a worsening of their conditions. In comparison to the control period, airway resistance was increased and the spirometric parameters were decreased. Mean values of sulphur dioxide for the investigated periods were 250 micrograms per cubic meter. The investigations have shown that even during relatively low immission loads small but consistent changes in suitable measuring values regarding lung functioning are identifiable.
Example of an experimental study Linder et al. (1988) investigated the effects of ozone on physical acti-
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vity. T h e y t e s t e d twelve h e a l t h y w o m e n and twelve h e a l t h y men on an exercise b i c y c l e until e x h a u s t i o n in a c l i m a t i c c h a m b e r at ozone levels of less than 8 m i c r o g r a m s per cubic m e t e r (the control), 120 to 140 and 245 to 260 m i c r o g r a m s per cubic meter. Ozone levels as h i g h as 200 m i c r o g r a m s per cubic m e t e r are often reached d u r i n g the summer m o n t h s in rural as well as u r b a n areas. U n d e r high ozone, a c l e a r d e c r e a s e of p e r f o r m a n c e was seen at maximal effort as well as a shift of the a n a e r o b i c t h r e s h o l d to somewhat lower p e r f o r m a n c e values. These changes are p r o b a b l y c a u s e d by i n c r e a s i n g l y d i f f i c u l t breathing. At high ozone c o n c e n t r a t i o n s , further symptoms w e r e recognized: itching of the throat and neck, thirst, fatigue and itching eyes. In addition, c o m p a r a b l e levels of e x e r c i s e were judged as m o r e strenuous.
EFFECTS OF A I R P O L L U T A N T S
In total, all i n v e s t i g a t i o n s to date have shown that the effects of air p o l l u t a n t s are m u l t i - f a c t o r i a l l y d e t e r m i n e d and often v e r y n o n - s p e c i f i c d i s o r d e r s are in the foreground. There is also no s p e c i f i c a i r - p o l l u t i o n disease. The c o m p l e x effects cannot be traced back to simple correlations, w h e r e b y every d e t e c t a b l e effect has a p a r t i c u l a r sole cause. A further d i f f i c u l t y is that the e n s u i n g d i s o r d e r s and d i s e a s e s in m a n y cases run their course slowly and so to speak in a h i d d e n fashion. The p u r p o s e is, however, to r e c o g n i z e d a m a g i n g p r o c e s s e s at an early stage, b e f o r e these speed up and reach a critical stage. That's why it is n e c e s s a r y to think in m u l t i f a c t o r i a l c o r r e l a t i o n s and to remove o u r s e l v e s from the old linear way of t h i n k i n g w h i c h only copes with m o n o c a u s a l relationships. Detrimental effects of air p o l l u t i o n on h e a l t h are (American T h o r a c i c Society, 1985): a n n o y a n c e from odors eye, nose and throat irritations - impairment of lung function - impairment of p h y s i c a l p e r f o r m a n c e i n c r e a s e d s u s c e p t i b i l i t y to r e s p i r a t o r y d i s e a s e s - i n c r e a s e d i n c i d e n c e of chronic b r o n c h i t i s and asthma i n c r e a s e d risk of c a r d i o v a s c u l a r d i s e a s e s The i n f l u e n c e of "air p o l l u t i o n factors", u n d e r the listed effects, depends on the type, c o n c e n t r a t i o n and d u r a t i o n of e x p o s u r e to the pollutant. -
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The m o s t i m p o r t a n t air p o l l u t a n t s c o n t r i b u t i n g to the d e v e l o p m e n t and to the course of h e a l t h d e t e r i o r a t i o n and d i s e a s e s are the irritants sulfur dioxide, n i t r o g e n d i o x i d e and ozone, but also s u s p e n d e d p a r t i c u l a t e s and acid aerosols. A l s o in keyword fashion, here are the h e a l t h effects of the individual p o l l u t a n t s as we know them t o d a y (Bundesamt fdr Umwelt, W a l d und Landschaft, 1986, 1988, 1989). These effects are always d e p e n d a n t on the c o n c e n t r a t i o n and the time of exposure, and on t h e i r c o m b i n a t i o n with other pollutants.
Sulfur d i o x i d e - This is an irritant of the eyes and the u p p e r r e s p i r a t o r y tract. At h i g h e r c o n c e n t r a t i o n s during deep b r e a t h i n g it is also active in the lower airways. It causes a n a r r o w i n g of the bronchial tubes, an increase in the flow r e s i s t a n c e of the r e s p i r a t o r y paths, an i m p a i r m e n t of lung capacity, impairment of the function of the c i l i a t e d e p i t h e l i u m and an increase in mucous secretion.
E f f e c t s of a t m o s p h e r i c p o l l u t i o n on h u m a n h e a l t h
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The acute e f f e c t s are - e s p e c i a l l y in c o m b i n a t i o n w i t h s u s p e n d e d p a r t i c u l a t e s - an i m p a i r m e n t of lung f u n c t i o n and for a s t h m a t i c s an i n c r e a s e d f r e q u e n c y of t h e i r attacks. -
- C h r o n i c e f f e c t s are m o r e f r e q u e n t r e s p i r a t o r y symptoms, lung f u n c t i o n and an i n c r e a s e in c h r o n i c bronchitis.
i m p a i r m e n t of
Nitroaen dioxide - This is an i r r i t a n t of the eyes and r e s p i r a t o r y tract. A c u t e e x p o s u r e causes an i n c r e a s e d air flow r e s i s t a n c e in the r e s p i r a t o r y tract. -
- W i t h long t e r m exposure, an i n c r e a s e in the f r e q u e n c y of c h r o n i c b r o n chitis, c o u g h i n g and e x p e c t o r a t i o n along w i t h d i s o r d e r s of lung functioning can be observed, p a r t i c u l a r l y in c o m b i n a t i o n w i t h s u s p e n d e d p a r t i c u l a t e s and s u l f u r dioxide.
Ozone An i r r i t a n t of the eyes and r e s p i r a t o r y tract. B e c a u s e of its low w a t e r s o l u b i l i t y it can e a s i l y p e n e t r a t e into the small airways. -
D u r i n g e x p e r i m e n t a l i n v e s t i g a t i o n s the f o l l o w i n g e f f e c t s h a v e b e e n observed, d e p e n d i n g on the type of exposure: i r r i t a t i o n r e a c t i o n s of the t i s s u e s w i t h b i o c h e m i c a l and m o r p h o l o g i c a l c h a n g e s (alveolar, e p i t h e l i a l and c i l i a t e d epithelial), t r i g g e r i n g of i n f l a m m a t o r y processes, d a m a g e of m a c r o p h a g e s w h i c h are i m p o r t a n t for r e s i s t a n c e to infections, as well as f u n c t i o n a l d i s o r d e r s of the lung. -
- A c u t e e f f e c t s are - d e p e n d i n g on the c o n c e n t r a t i o n and d u r a t i o n of e x p o s u r e - i r r i t a t i o n of the eyes and r e s p i r a t o r y t r a c t and a d e c r e a s e of lung function. T h e r e are g r e a t d i f f e r e n c e s in s u s c e p t i b i l i t y a m o n g h e a l t h y adults and also c h i l d r e n as well as p e o p l e s u f f e r i n g from o t h e r lung diseases. W i t h s t r e n u o u s p h y s i c a l e x e r c i s e the o c c u r e n c e of i r r i t a t i o n s is i n c r e a s e d and the p h y s i c a l p e r f o r m a n c e level (for e x a m p l e in e n d u r a n c e sports) can be decreased. F r e q u e n t l y r e p e a t e d ozone e x p o s u r e can h a v e an i n f l u e n c e on the development and the c o u r s e of r e s p i r a t o r y disorders. In areas w i t h h i g h ozone c o n c e n t r a t i o n s a g r e a t e r f r e q u e n c y of r e s p i r a t o r y s y m p t o m s and a d e c r e a s e of lung f u n c t i o n can be o b s e r v e d in the population. -
SUsDended particulates S u s p e n d e d p a r t i c u l a t e s can be a c a r r i e r of sulfates, m e t a l s and of p o l y c y c l i c h y d r o c a r b o n s . -
nitrates,
heavy
- F r o m a h e a l t h p o i n t of v i e w the p e r c e n t a g e s of the r e s p i r a b l e fractions are of importance: P a r t i c u l a t e s w i t h a d i a m e t e r of m o r e t h a n about i0 m i c r o n s get t r a p p e d in the n a s o - p h a r y n g e a l c a v i t y and p a r t i c u l a t e s of less than 3 - 5 m i c r o n s can p e n e t r a t e into the alveoli. E p i d e m i o l o g i c a l s t u d i e s show c o r r e l a t i o n s b e t w e e n the c o n c e n t r a t i o n of s u l f a t e s and n i t r a t e s in the r e s p i r a b l e p a r t i c u l a t e s and the o c c u r r e n c e of chronic d i s o r d e r s of the r e s p i r a t o r y tracts, p a r t i c u l a r l y b r o n c h i t i s and -
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asthma.
Acid aerosols - In e x p e r i m e n t a l studies a d v e r s e effects on the lung f u n c t i o n and airway r e s i s t a n c e of a s t h m a t i c s have been shown from s u l f u r i c acid aerosols. - In e p i d e m i o l o g i c a l studies c o r r e l a t i o n s b e t w e e n the e s t i m a t e d s u l f u r i c acid c o n c e n t r a t i o n and w i t h m o r t a l i t y and d i s o r d e r s of the r e s p i r a t o r y tracts have been observed. Only a few m o r e recent e p i d e m i o l o g i c a l studies have i n c l u d e d m e a s u r e m e n t s of the acid c o m p o n e n t s in aerosols. The q u e s t i o n r e m a i n s open w h i c h c o m p o n e n t s of the acid a e r o s o l s are the m o s t s u i t a b l e i n d i c a t o r s of the effects and by w h i c h m e t h o d s the p o l l u t a n t s s h o u l d be measured. W h e t h e r or not the acid aerosols, a l o n g s i d e the k n o w n p o l l u t a n t s such as o z o n e and n i t r o g e n dioxide, m i g h t be new i n d i c a t o r s of h e a l t h e f f e c t s m u s t be shown by further studies. -
AIR QUALITY
GUIDELINES
The q u e s t i o n now arises w h a t c o n c e n t r a t i o n s of the i n d i v i d u a l p o l l u t a n t s are a c c e p t i b l e from a h e a l t h perspective. In a d d i t i o n it is n e c e s s a r y to c o n s i d e r the p r o t e c t i o n of the environment. For this p u r p o s e air q u a l i t y g u i d e l i n e s and air q u a l i t y s t a n d a r d s have b e e n established. T h e s e are b a s e d - as for example, the air q u a l i t y g u i d e l i n e s p u b l i s h e d b y the W o r l d H e a l t h O r g a n i z a t i o n (1987) - p a r t i c u l a r l y on the e f f e c t s of air p o l l u t a n t s on h u m a n h e a l t h made k n o w n by s c i e n t i f i c i n v e s t i g a t i o n s . H e a l t h and wellbeing, as u n d e r s t o o d by the W o r l d H e a l t h O r g a n i z a t i o n (WHO), are only p o s s i b l e over the long term in a h e a l t h y environment. For this r e a s o n e c o t o x i c o l o g i c a l c r i t e r i a are also c o n s i d e r e d in the e v a l u a t i o n of air p o l l u t i o n effects. In r e f e r e n c e to t h e s e W H O g u i d e l i n e s c o n s i d e r e d (Achermann, 1988):
the f o l l o w i n g
p o i n t s m u s t be
- The g u i d e l i n e s w h i c h have been w o r k e d out to p r o t e c t the g e n e r a l p u b l i c are v a l i d as a rule only for individual pollutants. The s i m u l t a n e o u s o c c u r r e n c e of d i f f e r e n t p o l l u t a n t s can h o w e v e r p r o d u c e s t r o n g e r (additive, synergistic) or in c e r t a i n cases also w e a k e r (antagonistic) r e s u l t i n g effects. As yet the c o m b i n e d e f f e c t s of air p o l l u t a n t s have in general not been i n v e s t i g a t e d sufficiently, p a r t i c u l a r l y in the area of h u m a n toxicology. T h e y h a v e only been c o n s i d e r e d in individual c a s e s such as the c o m b i n a t i o n of s u l p h u r d i o x i d e and s u s p e n d e d p a r t i c u l a t e s . - T h e r e is no a b s o l u t e a s s u r a n c e that air p o l l u t i o n levels b e l o w the prop o s e d g u i d e l i n e s do not have d a m a g i n g effects. In p a r t i c u l a r , high risk groups such as c h i l d r e n and the ill can react m o r e sensitively. The simult a n e o u s o c c u r r e n c e of several p o l l u t a n t s can also lower the so c a l l e d e f f e c t threshold. - If the limits are exceeded, it does not m e a n that in immediately, d a m a g i n g e f f e c t s are to be expected. T h e r e i n c r e a s e d r i s k of a d v e r s e effects on h e a l t h w h i c h will and o f t e n will only be r e c o g n i z e d a f t e r l o n g e r p e r i o d s - When setting
the g u i d e l i n e s
no real d i s t i n c t i o n
e v e r y case, or will h o w e v e r be an g r a d u a l l y result of exposure.
is m a d e b e t w e e n
indoor
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and outdoor air pollution because, in relation to the investigated air pollutants, the same dose effect relationship would be valid for indoor as for outdoor areas. In relation to the frequency, the amount and the effect of immitted air pollutants outdoor pollution is considered to be more important because it not only effects human beings but also animals, vegetation, water and materials. - Guidelines for air quality do not have the importance of legally binding air quality standards. They are in a certain sense "values to be aimed for " and are part of the European WHO program "Health for All" within which all people of the European area should be protected by 1995 against recognized air pollution health risks.
Similar considerations are also valid for the Swiss air quality standards (Bundesamt f~r Umwelt, Wald und Landschaft, 1986) which, in accordance with Article 14 of the Federal Law on the Protection of the Environment, are to be established in accordance with the state of scientific knowledge or of experience, such that immissions below these standards; do not endanger human beings, animals or plants, their environment and biological communities. - do not seriously disturb the well-being of the population do not damage buildings - do not harm the fertility of the soil, vegetation and water quality. -
-
These effects must be judged individually and collectively in consideration of their combined effects (Article 8). Finally the effects on groups with increased susceptibility such as children, ill, the elderly, and pregnant women (Art 13).
the
Exceeding the immission limits always results in an increased risk of adverse health effects, damage to plants and even to whole ecosystems. The consequences are mostly recognized only gradually or after a long period. Therefore excesses also always signal the necessity and the urgency of implementing protective measures witMout further delay. Immission limits therefore have a double function: They are necessary for the evaluation of air quality and the possibility of damage; at the same time they are important instruments in the fight against air pollution. On the basis of the known pollution immissions in most countries, it is clear where the main emphasis for countermeasures needs to be placed. Particularly the emissions of nitrous oxides and hydrocarbons the precursor pollutants of ozone - need to be reduced. In countries which use coal and heavy oils for their energy production, the pollution from particulates and sulfur compounds must of course also be urgently reduced. -
Finally we have to note that by far the greatest challenge is the stru~ale aaainst areenhouse effect global warminq. For this reason a drastic reduction in the use of fossil fuels is urgent, as carbon dioxide contributes up to 50 % of the greenhouse effect. The worldwide consumption of heating oils, benzine and aviation fuel are still increasing. This use should be reduced as soon as possible. More efficient fuel use and the promotion of alternative energies - in particular solar energy - are therefore necessary. These are also long term the most effective measures against air pollution.
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REFERENCES
Achermann, B. (1988). Die schweizerischen Immissionsgrenzwerte im SDieuel neuer internationaler Luftaualit~ts~iGhtlinien. Bulletin des Bundesamtes f~r Umwelt, Wald und Landschaft, No. 2, 13-21. American Thoracic Society (1985). Guidelines as to what constitutes an adverse respiratory health effect, with special reference to epidemiologic studies of air pollution. ~ . Ref. Resp. Dis., 131, 666-668. Braun-Fahrl~nder, Ch., Ackermann-Liebrich, U., Wanner, Rutishauser, M., Minder, Ch.E. (1989). Auswirkungen stoffen auf die Atemwege von Kleinkindern. Schweiz. 119, 1424-1433.
H.U., von Luftschadmed. Wschr.,
Bundesamt f~r Umwelt, Wald und Landschaft (1986). Immissionsurenzwerte f~r Luftschadstoffe. Schriftenreihe Umweltschutz, Nr. 52, Bern. Bundesamt f~r Umwelt, Wald und Landschaft (1988). Luftverschmutzunu und Gesundheit. Schriftenreihe Umweltschutz Nr. 87, Bern. Bundesamt f~r Umwelt, Wald und Landschaft (1989). Ozon in der SchWeiz. Schriftenreihe Umweltschutz, Nr. i01, Bern. Chapman, R.S., Calafiore, D.C. and Hasselblad, V. (1985). Prevalence of persisent cough and phlegm in young adults in relation to long term ambient sulfur oxide exposure. Am. Rev. Respir. Dis., 132, 261-267. Euler, G.L., Abbey, D.E., Hodgkin, J.E. and Magie, A.R. (1987). Chronic Obstructive Pulmonary Disease Symptom Effects of Long-Term Cumulative Exposure to Ambient Levels of Total Suspended Particulates and Sulfur Dioxide in California Seventh-day Adventists Residents. Archives of Environmental Health, 42, 213-222. Euler, G.L., Abbey, D.E., Hodgkin, J.E. and Magie, A.R. (1988). Chronic Obstructive Pulmonary Disease Symptom Effects of Long-Term Cumulative Exposure to Ambient Levels of Total Oxidants and Nitrogen Dioxide in CalifOrnia Seventh-day Adventists Residents. Archives of ~nvironmental Health, 43, 279-285. Linder, J., Herren, D., Monn, Ch. und Wanner, H.U. (1988). Die Wirkung von Ozon auf die k6rperliche Leistungsf~higkeit. Schweiz. Ztschr. SDortmed., 36, 5-10. Mostardi, R.A., Ely, D.L., Woebkenberg, N.R., Richardson, B. and Jarrett, M.T. (1981). The university of Akron Study on Air Pollution and Human Health Effects. I. Methodology, Baseline Data, and Aerometrics. II. Effects on Acute Respiratory Illness. Archives of EDvironmenta~ Heal~h, 36, 243-255. Van Eimeren, W. und Horisberger, B. (1987). Umwelt und Gesundheit Statistisch methodische Aspekte von epdiemiologischen Studien ~ber die Wirkung von Umweltfaktoren auf die menschliche Gesundheit. Springer Verlag Berlin-Heidelberg. Wichmann, H.E., Sugiri, D., Mohammed Serajul, Islam, Haake, D. and Roscovann, A. (1988). Lungenfunktion und Carboxyh~moglobin in der Smogsituation des Januar 1987. Zbl. Bakt. Hyq. B. 187, 31-43. World Health Organization (1987). Air Quality Guidelines for Europe. WHO Regional Publications. European Series No. 23, Copenhagen.
0021-8502/90 $3.00 + 0.00 Pergamon Press plc
E F F E C T S OF A T M O S P H E R I C P O L L U T I O N ON H U M A N H E A L T H
H.U. W a n n e r
D e p a r t m e n t of H y g i e n e and A p p l i e d Physiology, Federal I n s t i t u t e of Technology, ETH-Zentrum, CH 8092 Z u r i c h
ABSTRACT
M o s t air p o l l u t a n t s do not lead to s p e c i f i c diseases. D e p e n d i n g on the pollutant, the c o n c e n t r a t i o n and the d u r a t i o n of e x p o s u r e some organs are m o r e a f f e c t e d t h a n others. The m o s t frequent d i s o r d e r s are t h o s e c a u s e d by i r r i t a n t g a s e s and p a r t i c u l a t e s on the m u c o u s m e m b r a n e s and r e s p i r a t o r y organs. The c o n s e q u e n c e s are eye, nose and t h r o a t inflammations, dimin i s h e d lung function, i n c r e a s e d s u s c e p t a b i l i t y to r e s p i r a t o r y i n f e c t i o n and a h i g h e r i n c i d e n c e of c h r o n i c bronchitis. T h e s e d i s o r d e r s and d i s e a s e s are, of course, i n f l u e n c e d by o t h e r factors as well, such as immune deficiency, allergies, o c c u p a t i o n a l e x p o s u r e to pollutants, and p a r t i c u l a r l y smoking. The e f f e c t s of air p o l l u t a n t s are, therefore, m u l t i f a c t o r i a l l y c o n d i t i o n e d and n o n s p e c i f i c d i s o r d e r s are p l a c e d in the foreground. Evid e n c e for an a s s o c i a t i o n of air p o l l u t i o n w i t h a d v e r s e effects on h u m a n h e a l t h is d r a w n from three sources: animal experiments, e x p e r i m e n t a l human exposures, and e p i d e m i o l o g i c studies of e x p o s e d h u m a n populations. The b u r d e n of a t m o s p h e r i c p o l l u t i o n m u s t be r e d u c e d to p r o t e c t h u m a n h e a l t h by an a d e q u a t e s a f e t y margin. In particular, the i n c r e a s e d s e n s i t i v i t y of sick and aged p e o p l e as well as c h i l d r e n should be t a k e n into account. In d e f i n i n g the m a x i m u m i m m i s s i o n levels, p r e v e n t i v e a s p e c t s s h o u l d h a v e p r i o r i t y so as to k e e p the r i s k of d a m a g e to h e a l t h and the h a r m f u l influences on the e n v i r o n m e n t to a minimum.
KEYWORDS
Air p o l l u t a n t s ; h e a l t h effects; studies; air q u a l i t y standards.
epidemiological
studies;
experimental
M E T H O D S FOR P R O V I N G H E A L T H EFFECTS
T o d a y we h a v e r e l e v a n t s c i e n t i f i c m e t h o d s by w h i c h the i n f l u e n c e of div e r s e factors can be i n v e s t i g a t e d and considered. W i t h t h e s e we can m a k e s t a t e m e n t s a b o u t the e f f e c t s of air p o l l u t i o n on h u m a n b e i n g s and the environment. For a c o m p r e h e n s i v e evaluation, however, m u l t i p l e i n v e s t i g a tions u s i n g d i f f e r e n t types of field e q u i p m e n t and p o s i n g d i f f e r e n t types of q u e s t i o n s are a l w a y s necessary. The two m o s t i m p o r t a n t study m e t h o d s for p r o v i n g the e f f e c t s of air p o l l u t i o n on h e a l t h are e p i d e m i o l o a i c a l inv e s t i q a t i o n s and e x p e r i m e n t a l studies (Van E i m e r e n and Horisberger, 1987).
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E p i d e m i o l o g i c a l studies are i n v e s t i g a t i o n s for e s t a b l i s h i n g the effects of the actual air p o l l u t i o n load on a p a r t i c u l a r p o p u l a t i o n group. We differentiate b e t w e e n " c r o s s - s e c t i o n a l studies", in w h i c h the f r e q u e n c y of part i c u l a r h e a l t h p r o b l e m s in areas with d i f f e r e n t air p o l l u t i o n levels are compared, and " l o n a i t u d i n a l studies" w h e r e c o m p a r a t i v e o b s e r v a t i o n s are made of the same p o p u l a t i o n groups while u n d e r e x p o s u r e to lower and h i g h e r air p o l l u t i o n levels. (For example before, d u r i n g and after smog episodes). The m e a n i n g f u l n e s s of such studies d e p e n d s on the size of the i n v e s t i g a t e d group, the size of the sought or o b s e r v e d d i f f e r e n c e concerning h e a l t h effects, and the level of pollution. The d i s t r i b u t i o n in relation to age, sex, general health and social status m u s t be c o m p a r a b l e betw e e n the i n v e s t i g a t e d groups. Furthermore, we m u s t take into account the influence of i n t e r v e n i n g factors such as smoking habits, o c c u p a t i o n a l exposure and climate.
E x P e r i m e n t a l studies e s t a b l i s h the effects of individual p o l l u t a n t s or m i x t u r e s of p o l l u t a n t s d e p e n d i n g on the dosage, time of exposure, the physical activity, t e m p e r a t u r e and the air humidity. These studies are c o n d u c t e d w i t h v o l u n t a r y subjects by s t a n d a r d i z e d m e t h o d s and u n d e r p r e c i s e l y c o n t r o l l e d conditions. The results are v a l i d for the investigated group u n d e r the c o n t r o l l e d e x p e r i m e n t a l conditions. T h e y have only limited g e n e r a l i t y to c o n d i t i o n s in the real e n v i r o n m e n t w h e r e there are d i f f e r e n t m i x t u r e s of p o l l u t a n t s and c h a n g i n g c l i m a t i c conditions.
The f o l l o w i n g results of i n v e s t i g a t i o n s have shown a c o r r e l a t i o n b e t w e e n the f r e q u e n c y of chronic r e s p i r a t o r y d i s e a s e s and r e s p i r a t o r y symptoms in h e a l t h y p e r s o n s (adults and children) w i t h the e x t e n t of air p o l l u t i o n over e x t e n d e d periods of time.
E x a m p l e s of "cross sectional studies" Chapman et al. (1985) m a d e c r o s s - s e c t i o n a l i n v e s t i g a t i o n s in four cities which had d i f f e r e n t levels of p o l l u t i o n in Utah, in the USA. They interv i e w e d in total 5623 m o t h e r s and fathers of school children. T h e y established the l o n g - t e r m effect of r e l a t i v e l y low c o n c e n t r a t i o n s of sulphur dioxide on the f r e q u e n c y of chronic coughs and expectoration. In the most h e a v i l y e x p o s e d city (Magna) the average 5-year v a l u e s of s u l p h u r dioxide c o n c e n t r a t i o n s w e r e 115 m i c r o g r a m s per cubic m e t e r and of s u l f a t e s 14 micrograms per cubic meter. In the other cities the r e s p e c t i v e v a l u e s lay b e t w e e n ii and 36, r e s p e c t i v e l y 5 and 8 m i c r o g r a m s per cubic meter. The p r e v a l e n c e of c h r o n i c coughs and e x p e c t o r a t i o n in M a g n a for the non-smoking m o t h e r s was 4.2% and for the n o n - s m o k i n g fathers 7.8% on average. For the s m o k i n g m o t h e r s the p r e v a l e n c e was 21.8% and for the s m o k i n g fathers 22.2% on average. In the other cities the r e s p e c t i v e p r e v a l e n c e s were s i g n i f i c a n t l y lower, on average 2% or 17% respectively. No s i g n i f i c a n t d i f f e r e n c e was found b e t w e e n the cities with low p o l l u t i o n levels. M o s t a r d i et al. (1981) i n v e s t i g a t e d lung function v a l u e s and the frequency of r e s p i r a t o r y s y m p t o m s among 146 c h i l d r e n in the age g r o u p i0 to ii in an area w i t h h e a v y p o l l u t i o n and also 153 c h i l d r e n in the same age group in an area of low pollution. The frequency of r e s p i r a t o r y s y m p t o m s (coughing, runny noses, hoarseness, colds, irritation of the eyes) was e s t a b l i s h e d by a q u e s t i o n n a i r e filled in by the parents. Lung functions w e r e m e a s u r e d by means of a s p i r o m e t e r at school. At the school w i t h the h i g h e r p o l l u t i o n load the m e a n daily values during the school year for s u l p h u r dioxide were 77 and for n i t r o g e n d i o x i d e 54 m i c r o g r a m s per cubic meter. Individual symptoms per day w e r e about twice as frequent than in the school with less
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pollution (sulphur dioxide 21 and nitrogen dioxide 37 micrograms per cubic meter). Furthermore the lung function values during acute respiratory tract infections showed a larger degree of disorder. Braun et al. (1989) investigated the association between air pollutionand respiratory symptoms in a diary study on a random sample of 1063 Swiss children aged from 0 to 5 years in four different areas of switzerland (two urban, a suburban and a rural area). Passive samplers inside and outside the home measured nitrogen dioxide concentration over 6 weeks. During this time diaries were filled out by parents. 20% of them were validated with the attending pediatrician's case notes and were in good agreement. The frequency of respiratory symptoms per child per day was found to increase with increasing levels of nitrogen dioxide measured outdoors. The relationship was more significant for the non smoking families with Swiss children. Possible other factors were accounted for by multiple regression analysis; the variables "season" and "child's susceptibility to colds" also showed a significant association with respiratory symptoms. But the relationship between nitrogen dioxide outdoors and respiratory symptoms per child per day remained statistically significant. The result indicates that air pollution is a contributory factor in the development of respiratory symptoms in children. Euler et al. (1987, 1988) investigated the effect on the frequency of chronic obstructive airways disease from long term exposure to airborne dust pollution and sulphur dioxide, using a questionnaire from the National Heart, Lung and Blood Institute. Their subjects were a group of healthy adults. The relative risk, 1.18, under a concentration of sulphur dioxide of more than 105 micrograms per cubic meter over 500 hours per year, was significantly increased. With a concentration of airborne dust particles of more than 150 micrograms per cubic meter (2500 hours per year) a relative risk of 1.32 was also found. The same test group was exposed to oxidants at a concentration of more than 200 micrograms per cubic meter over 750 hours per year and the relative risk for chronic respiratory diseases (1.20) was higher than over an exposure time of 250 hours per year (1.07). With a concentration of more than 300 micrograms per cubic meter the relative risk increased with the time of exposure. Exposure to nitrogen dioxide did not show a significant correlation whereby only a small part of the population group under investigation was exposed to values over i00 micrograms per cubic meter. Passive smoking at work increased the prevalence of bronchitis significantly.
Example of a "lonqitudinal
study"
Wichmann et al. (1988) made measurements of lung function during smog periods in 1981 using different population groups, iii healthy workers from the areas of Cologne and Dusseldorf who were not occupationally exposed, showed increased airway resistance during the smog period in comparison to the control period. Additionally 59 patients with slight obstructive airway disease who came from diverse regions of Germany showed a worsening of their conditions. In comparison to the control period, airway resistance was increased and the spirometric parameters were decreased. Mean values of sulphur dioxide for the investigated periods were 250 micrograms per cubic meter. The investigations have shown that even during relatively low immission loads small but consistent changes in suitable measuring values regarding lung functioning are identifiable.
Example of an experimental study Linder et al. (1988) investigated the effects of ozone on physical acti-
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vity. T h e y t e s t e d twelve h e a l t h y w o m e n and twelve h e a l t h y men on an exercise b i c y c l e until e x h a u s t i o n in a c l i m a t i c c h a m b e r at ozone levels of less than 8 m i c r o g r a m s per cubic m e t e r (the control), 120 to 140 and 245 to 260 m i c r o g r a m s per cubic meter. Ozone levels as h i g h as 200 m i c r o g r a m s per cubic m e t e r are often reached d u r i n g the summer m o n t h s in rural as well as u r b a n areas. U n d e r high ozone, a c l e a r d e c r e a s e of p e r f o r m a n c e was seen at maximal effort as well as a shift of the a n a e r o b i c t h r e s h o l d to somewhat lower p e r f o r m a n c e values. These changes are p r o b a b l y c a u s e d by i n c r e a s i n g l y d i f f i c u l t breathing. At high ozone c o n c e n t r a t i o n s , further symptoms w e r e recognized: itching of the throat and neck, thirst, fatigue and itching eyes. In addition, c o m p a r a b l e levels of e x e r c i s e were judged as m o r e strenuous.
EFFECTS OF A I R P O L L U T A N T S
In total, all i n v e s t i g a t i o n s to date have shown that the effects of air p o l l u t a n t s are m u l t i - f a c t o r i a l l y d e t e r m i n e d and often v e r y n o n - s p e c i f i c d i s o r d e r s are in the foreground. There is also no s p e c i f i c a i r - p o l l u t i o n disease. The c o m p l e x effects cannot be traced back to simple correlations, w h e r e b y every d e t e c t a b l e effect has a p a r t i c u l a r sole cause. A further d i f f i c u l t y is that the e n s u i n g d i s o r d e r s and d i s e a s e s in m a n y cases run their course slowly and so to speak in a h i d d e n fashion. The p u r p o s e is, however, to r e c o g n i z e d a m a g i n g p r o c e s s e s at an early stage, b e f o r e these speed up and reach a critical stage. That's why it is n e c e s s a r y to think in m u l t i f a c t o r i a l c o r r e l a t i o n s and to remove o u r s e l v e s from the old linear way of t h i n k i n g w h i c h only copes with m o n o c a u s a l relationships. Detrimental effects of air p o l l u t i o n on h e a l t h are (American T h o r a c i c Society, 1985): a n n o y a n c e from odors eye, nose and throat irritations - impairment of lung function - impairment of p h y s i c a l p e r f o r m a n c e i n c r e a s e d s u s c e p t i b i l i t y to r e s p i r a t o r y d i s e a s e s - i n c r e a s e d i n c i d e n c e of chronic b r o n c h i t i s and asthma i n c r e a s e d risk of c a r d i o v a s c u l a r d i s e a s e s The i n f l u e n c e of "air p o l l u t i o n factors", u n d e r the listed effects, depends on the type, c o n c e n t r a t i o n and d u r a t i o n of e x p o s u r e to the pollutant. -
-
-
-
The m o s t i m p o r t a n t air p o l l u t a n t s c o n t r i b u t i n g to the d e v e l o p m e n t and to the course of h e a l t h d e t e r i o r a t i o n and d i s e a s e s are the irritants sulfur dioxide, n i t r o g e n d i o x i d e and ozone, but also s u s p e n d e d p a r t i c u l a t e s and acid aerosols. A l s o in keyword fashion, here are the h e a l t h effects of the individual p o l l u t a n t s as we know them t o d a y (Bundesamt fdr Umwelt, W a l d und Landschaft, 1986, 1988, 1989). These effects are always d e p e n d a n t on the c o n c e n t r a t i o n and the time of exposure, and on t h e i r c o m b i n a t i o n with other pollutants.
Sulfur d i o x i d e - This is an irritant of the eyes and the u p p e r r e s p i r a t o r y tract. At h i g h e r c o n c e n t r a t i o n s during deep b r e a t h i n g it is also active in the lower airways. It causes a n a r r o w i n g of the bronchial tubes, an increase in the flow r e s i s t a n c e of the r e s p i r a t o r y paths, an i m p a i r m e n t of lung capacity, impairment of the function of the c i l i a t e d e p i t h e l i u m and an increase in mucous secretion.
E f f e c t s of a t m o s p h e r i c p o l l u t i o n on h u m a n h e a l t h
$393
The acute e f f e c t s are - e s p e c i a l l y in c o m b i n a t i o n w i t h s u s p e n d e d p a r t i c u l a t e s - an i m p a i r m e n t of lung f u n c t i o n and for a s t h m a t i c s an i n c r e a s e d f r e q u e n c y of t h e i r attacks. -
- C h r o n i c e f f e c t s are m o r e f r e q u e n t r e s p i r a t o r y symptoms, lung f u n c t i o n and an i n c r e a s e in c h r o n i c bronchitis.
i m p a i r m e n t of
Nitroaen dioxide - This is an i r r i t a n t of the eyes and r e s p i r a t o r y tract. A c u t e e x p o s u r e causes an i n c r e a s e d air flow r e s i s t a n c e in the r e s p i r a t o r y tract. -
- W i t h long t e r m exposure, an i n c r e a s e in the f r e q u e n c y of c h r o n i c b r o n chitis, c o u g h i n g and e x p e c t o r a t i o n along w i t h d i s o r d e r s of lung functioning can be observed, p a r t i c u l a r l y in c o m b i n a t i o n w i t h s u s p e n d e d p a r t i c u l a t e s and s u l f u r dioxide.
Ozone An i r r i t a n t of the eyes and r e s p i r a t o r y tract. B e c a u s e of its low w a t e r s o l u b i l i t y it can e a s i l y p e n e t r a t e into the small airways. -
D u r i n g e x p e r i m e n t a l i n v e s t i g a t i o n s the f o l l o w i n g e f f e c t s h a v e b e e n observed, d e p e n d i n g on the type of exposure: i r r i t a t i o n r e a c t i o n s of the t i s s u e s w i t h b i o c h e m i c a l and m o r p h o l o g i c a l c h a n g e s (alveolar, e p i t h e l i a l and c i l i a t e d epithelial), t r i g g e r i n g of i n f l a m m a t o r y processes, d a m a g e of m a c r o p h a g e s w h i c h are i m p o r t a n t for r e s i s t a n c e to infections, as well as f u n c t i o n a l d i s o r d e r s of the lung. -
- A c u t e e f f e c t s are - d e p e n d i n g on the c o n c e n t r a t i o n and d u r a t i o n of e x p o s u r e - i r r i t a t i o n of the eyes and r e s p i r a t o r y t r a c t and a d e c r e a s e of lung function. T h e r e are g r e a t d i f f e r e n c e s in s u s c e p t i b i l i t y a m o n g h e a l t h y adults and also c h i l d r e n as well as p e o p l e s u f f e r i n g from o t h e r lung diseases. W i t h s t r e n u o u s p h y s i c a l e x e r c i s e the o c c u r e n c e of i r r i t a t i o n s is i n c r e a s e d and the p h y s i c a l p e r f o r m a n c e level (for e x a m p l e in e n d u r a n c e sports) can be decreased. F r e q u e n t l y r e p e a t e d ozone e x p o s u r e can h a v e an i n f l u e n c e on the development and the c o u r s e of r e s p i r a t o r y disorders. In areas w i t h h i g h ozone c o n c e n t r a t i o n s a g r e a t e r f r e q u e n c y of r e s p i r a t o r y s y m p t o m s and a d e c r e a s e of lung f u n c t i o n can be o b s e r v e d in the population. -
SUsDended particulates S u s p e n d e d p a r t i c u l a t e s can be a c a r r i e r of sulfates, m e t a l s and of p o l y c y c l i c h y d r o c a r b o n s . -
nitrates,
heavy
- F r o m a h e a l t h p o i n t of v i e w the p e r c e n t a g e s of the r e s p i r a b l e fractions are of importance: P a r t i c u l a t e s w i t h a d i a m e t e r of m o r e t h a n about i0 m i c r o n s get t r a p p e d in the n a s o - p h a r y n g e a l c a v i t y and p a r t i c u l a t e s of less than 3 - 5 m i c r o n s can p e n e t r a t e into the alveoli. E p i d e m i o l o g i c a l s t u d i e s show c o r r e l a t i o n s b e t w e e n the c o n c e n t r a t i o n of s u l f a t e s and n i t r a t e s in the r e s p i r a b l e p a r t i c u l a t e s and the o c c u r r e n c e of chronic d i s o r d e r s of the r e s p i r a t o r y tracts, p a r t i c u l a r l y b r o n c h i t i s and -
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H. U. W A N N E R
asthma.
Acid aerosols - In e x p e r i m e n t a l studies a d v e r s e effects on the lung f u n c t i o n and airway r e s i s t a n c e of a s t h m a t i c s have been shown from s u l f u r i c acid aerosols. - In e p i d e m i o l o g i c a l studies c o r r e l a t i o n s b e t w e e n the e s t i m a t e d s u l f u r i c acid c o n c e n t r a t i o n and w i t h m o r t a l i t y and d i s o r d e r s of the r e s p i r a t o r y tracts have been observed. Only a few m o r e recent e p i d e m i o l o g i c a l studies have i n c l u d e d m e a s u r e m e n t s of the acid c o m p o n e n t s in aerosols. The q u e s t i o n r e m a i n s open w h i c h c o m p o n e n t s of the acid a e r o s o l s are the m o s t s u i t a b l e i n d i c a t o r s of the effects and by w h i c h m e t h o d s the p o l l u t a n t s s h o u l d be measured. W h e t h e r or not the acid aerosols, a l o n g s i d e the k n o w n p o l l u t a n t s such as o z o n e and n i t r o g e n dioxide, m i g h t be new i n d i c a t o r s of h e a l t h e f f e c t s m u s t be shown by further studies. -
AIR QUALITY
GUIDELINES
The q u e s t i o n now arises w h a t c o n c e n t r a t i o n s of the i n d i v i d u a l p o l l u t a n t s are a c c e p t i b l e from a h e a l t h perspective. In a d d i t i o n it is n e c e s s a r y to c o n s i d e r the p r o t e c t i o n of the environment. For this p u r p o s e air q u a l i t y g u i d e l i n e s and air q u a l i t y s t a n d a r d s have b e e n established. T h e s e are b a s e d - as for example, the air q u a l i t y g u i d e l i n e s p u b l i s h e d b y the W o r l d H e a l t h O r g a n i z a t i o n (1987) - p a r t i c u l a r l y on the e f f e c t s of air p o l l u t a n t s on h u m a n h e a l t h made k n o w n by s c i e n t i f i c i n v e s t i g a t i o n s . H e a l t h and wellbeing, as u n d e r s t o o d by the W o r l d H e a l t h O r g a n i z a t i o n (WHO), are only p o s s i b l e over the long term in a h e a l t h y environment. For this r e a s o n e c o t o x i c o l o g i c a l c r i t e r i a are also c o n s i d e r e d in the e v a l u a t i o n of air p o l l u t i o n effects. In r e f e r e n c e to t h e s e W H O g u i d e l i n e s c o n s i d e r e d (Achermann, 1988):
the f o l l o w i n g
p o i n t s m u s t be
- The g u i d e l i n e s w h i c h have been w o r k e d out to p r o t e c t the g e n e r a l p u b l i c are v a l i d as a rule only for individual pollutants. The s i m u l t a n e o u s o c c u r r e n c e of d i f f e r e n t p o l l u t a n t s can h o w e v e r p r o d u c e s t r o n g e r (additive, synergistic) or in c e r t a i n cases also w e a k e r (antagonistic) r e s u l t i n g effects. As yet the c o m b i n e d e f f e c t s of air p o l l u t a n t s have in general not been i n v e s t i g a t e d sufficiently, p a r t i c u l a r l y in the area of h u m a n toxicology. T h e y h a v e only been c o n s i d e r e d in individual c a s e s such as the c o m b i n a t i o n of s u l p h u r d i o x i d e and s u s p e n d e d p a r t i c u l a t e s . - T h e r e is no a b s o l u t e a s s u r a n c e that air p o l l u t i o n levels b e l o w the prop o s e d g u i d e l i n e s do not have d a m a g i n g effects. In p a r t i c u l a r , high risk groups such as c h i l d r e n and the ill can react m o r e sensitively. The simult a n e o u s o c c u r r e n c e of several p o l l u t a n t s can also lower the so c a l l e d e f f e c t threshold. - If the limits are exceeded, it does not m e a n that in immediately, d a m a g i n g e f f e c t s are to be expected. T h e r e i n c r e a s e d r i s k of a d v e r s e effects on h e a l t h w h i c h will and o f t e n will only be r e c o g n i z e d a f t e r l o n g e r p e r i o d s - When setting
the g u i d e l i n e s
no real d i s t i n c t i o n
e v e r y case, or will h o w e v e r be an g r a d u a l l y result of exposure.
is m a d e b e t w e e n
indoor
Effects of atmospheric pollution on human health
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and outdoor air pollution because, in relation to the investigated air pollutants, the same dose effect relationship would be valid for indoor as for outdoor areas. In relation to the frequency, the amount and the effect of immitted air pollutants outdoor pollution is considered to be more important because it not only effects human beings but also animals, vegetation, water and materials. - Guidelines for air quality do not have the importance of legally binding air quality standards. They are in a certain sense "values to be aimed for " and are part of the European WHO program "Health for All" within which all people of the European area should be protected by 1995 against recognized air pollution health risks.
Similar considerations are also valid for the Swiss air quality standards (Bundesamt f~r Umwelt, Wald und Landschaft, 1986) which, in accordance with Article 14 of the Federal Law on the Protection of the Environment, are to be established in accordance with the state of scientific knowledge or of experience, such that immissions below these standards; do not endanger human beings, animals or plants, their environment and biological communities. - do not seriously disturb the well-being of the population do not damage buildings - do not harm the fertility of the soil, vegetation and water quality. -
-
These effects must be judged individually and collectively in consideration of their combined effects (Article 8). Finally the effects on groups with increased susceptibility such as children, ill, the elderly, and pregnant women (Art 13).
the
Exceeding the immission limits always results in an increased risk of adverse health effects, damage to plants and even to whole ecosystems. The consequences are mostly recognized only gradually or after a long period. Therefore excesses also always signal the necessity and the urgency of implementing protective measures witMout further delay. Immission limits therefore have a double function: They are necessary for the evaluation of air quality and the possibility of damage; at the same time they are important instruments in the fight against air pollution. On the basis of the known pollution immissions in most countries, it is clear where the main emphasis for countermeasures needs to be placed. Particularly the emissions of nitrous oxides and hydrocarbons the precursor pollutants of ozone - need to be reduced. In countries which use coal and heavy oils for their energy production, the pollution from particulates and sulfur compounds must of course also be urgently reduced. -
Finally we have to note that by far the greatest challenge is the stru~ale aaainst areenhouse effect global warminq. For this reason a drastic reduction in the use of fossil fuels is urgent, as carbon dioxide contributes up to 50 % of the greenhouse effect. The worldwide consumption of heating oils, benzine and aviation fuel are still increasing. This use should be reduced as soon as possible. More efficient fuel use and the promotion of alternative energies - in particular solar energy - are therefore necessary. These are also long term the most effective measures against air pollution.
H. U. WANNER
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REFERENCES
Achermann, B. (1988). Die schweizerischen Immissionsgrenzwerte im SDieuel neuer internationaler Luftaualit~ts~iGhtlinien. Bulletin des Bundesamtes f~r Umwelt, Wald und Landschaft, No. 2, 13-21. American Thoracic Society (1985). Guidelines as to what constitutes an adverse respiratory health effect, with special reference to epidemiologic studies of air pollution. ~ . Ref. Resp. Dis., 131, 666-668. Braun-Fahrl~nder, Ch., Ackermann-Liebrich, U., Wanner, Rutishauser, M., Minder, Ch.E. (1989). Auswirkungen stoffen auf die Atemwege von Kleinkindern. Schweiz. 119, 1424-1433.
H.U., von Luftschadmed. Wschr.,
Bundesamt f~r Umwelt, Wald und Landschaft (1986). Immissionsurenzwerte f~r Luftschadstoffe. Schriftenreihe Umweltschutz, Nr. 52, Bern. Bundesamt f~r Umwelt, Wald und Landschaft (1988). Luftverschmutzunu und Gesundheit. Schriftenreihe Umweltschutz Nr. 87, Bern. Bundesamt f~r Umwelt, Wald und Landschaft (1989). Ozon in der SchWeiz. Schriftenreihe Umweltschutz, Nr. i01, Bern. Chapman, R.S., Calafiore, D.C. and Hasselblad, V. (1985). Prevalence of persisent cough and phlegm in young adults in relation to long term ambient sulfur oxide exposure. Am. Rev. Respir. Dis., 132, 261-267. Euler, G.L., Abbey, D.E., Hodgkin, J.E. and Magie, A.R. (1987). Chronic Obstructive Pulmonary Disease Symptom Effects of Long-Term Cumulative Exposure to Ambient Levels of Total Suspended Particulates and Sulfur Dioxide in California Seventh-day Adventists Residents. Archives of Environmental Health, 42, 213-222. Euler, G.L., Abbey, D.E., Hodgkin, J.E. and Magie, A.R. (1988). Chronic Obstructive Pulmonary Disease Symptom Effects of Long-Term Cumulative Exposure to Ambient Levels of Total Oxidants and Nitrogen Dioxide in CalifOrnia Seventh-day Adventists Residents. Archives of ~nvironmental Health, 43, 279-285. Linder, J., Herren, D., Monn, Ch. und Wanner, H.U. (1988). Die Wirkung von Ozon auf die k6rperliche Leistungsf~higkeit. Schweiz. Ztschr. SDortmed., 36, 5-10. Mostardi, R.A., Ely, D.L., Woebkenberg, N.R., Richardson, B. and Jarrett, M.T. (1981). The university of Akron Study on Air Pollution and Human Health Effects. I. Methodology, Baseline Data, and Aerometrics. II. Effects on Acute Respiratory Illness. Archives of EDvironmenta~ Heal~h, 36, 243-255. Van Eimeren, W. und Horisberger, B. (1987). Umwelt und Gesundheit Statistisch methodische Aspekte von epdiemiologischen Studien ~ber die Wirkung von Umweltfaktoren auf die menschliche Gesundheit. Springer Verlag Berlin-Heidelberg. Wichmann, H.E., Sugiri, D., Mohammed Serajul, Islam, Haake, D. and Roscovann, A. (1988). Lungenfunktion und Carboxyh~moglobin in der Smogsituation des Januar 1987. Zbl. Bakt. Hyq. B. 187, 31-43. World Health Organization (1987). Air Quality Guidelines for Europe. WHO Regional Publications. European Series No. 23, Copenhagen.