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Air pollution and respiratory diseases in children in São Paulo, Brazil
Sm. SC;. Med.
Vol. 29. No. 8, pp. 959-964, 1989 Printed in Great Britain. All rights reserved
0277-9536/89f3.00 + 0.00
Copyright 0 1989Pergamon Press plc
AIR POLLUTION AND RESPIRATORY DISEASES CHILDREN IN SAO PAULO, BRAZIL
IN
HELENA RIBEIRO SOBRAL de Geografia, Pontificia Universidade Catolica de Slo Paulo, CP 7982, SHo Paulo, Brazil
Department0
Abstract-Air pollution in the huge conurbation of SHo Paulo, Brazil (13 million inhabitants) has been mapped from air quality monitoring stations. In three contrasted sample areas, children’s respiratory health parameters were collected to assess the roles of poverty and poor housing against those of air pollutton. Respiratory ill-health is clearly shown to vary with pollution levels and there is evidence that socio-economic conditions aggravate the problem. Key
words-air
pollution, child health, Sgo Paulo, Brazil, respiratory ill-health
INTRODUCTION The city of SZo Paulo has had a pre-eminent
role in
the Brazilian industrialization process since the first decades of this century and many districts with mixed functions have developed where industries and blue collar workers’ dwellings are found alongside each other. The State Pollution Control Agency (CETESB) has been monitoring air quality in-the metropolitan area only since 1973 but no previous studies have been done to verify the long term effects of air pollution on health. Yet respiratory diseases are known to be the second major cause of death in the city of SHo Paulo, a case unique in Brazil. The problem is even more serious because over 13,000,OOO people live in the metropolitan area. These facts motivated this study to ascertain whether there is a relationship between air pollution, which is quite severe in some areas, and the prevalence of respiratory diseases. METHODOLOGY
The first step was to map pollution by SO2 and by dust particles using the average of 11 yrs’ records for the metropolitan area, based on data collected by 39 CETESB monitoring stations. The mapping of CO and of photochemical pollutants was not possible because their levels are registered only at very few monitoring stations. The second step was to select three areas for study; one with a very low pollution level, Juquitiba, to be used as a control area; one with a medium pollution level, Osasco, just lower than the CETESB Air Quality Standard; and one with very high pollution all the year, Tatuape (Figs l-3). An epidemiological enquiry was carried out in each of these three among children 12 and 13 yr old. Longitudinal studies had been recommended by WHO [I] for areas where no previous investigation on the effects of air pollution on health had been done. Children at this age were chosen because among them the effects of occupational pollution and of smoking could be controlled and also at this age they are able adequately to answer the questionnaires.
The questionnaires used were developed by the Epidemiology Standardization Project [2] for children under 13 yr old and were applied in government schools located within 2 km distance from the monitoring stations in Tatuape (three schools), Osasco (three schools) and Juquitiba (one school only). All the children from this age group were listed and then a sample was selected with the size of the sample established from the formula: No.
n=
1+7
No.-1
where No. = $Q, P
P = prevalence rate of a disease expressed as a proportion of the total population, Q = complement (Q = 1 - P), TV= standard error of the prevalence P, ?p adopted was 5%, considered adequate for epidemiological studies and within the financial and personnel constraints of this project. Since the prevalence rates of many respiratory diseases were unknown, 50% was adopted as the rate that would require a larger number of questionnaires in order to minimize the chances of error. That meant that in each area at least 100 questionnaires had to be administered. In Juquitiba there were 140 children of this age group and they were all interviewed, in Tatuape 145 were interviewed and in Osasco 108. The survey was carried on in September, October and November in all three areas in order to avoid the influence of acute episodes of air pollution which often occur during winter and during spells of cold weather. In addition to these questionnaires another 21 were filled in by children of the same age group living in slums in Tatuape to find out whether social conditions in polluted areas had any influence on the prevalence rates of respiratory diseases. This was necessary because the analysis of the results showed that among children with illiterate parents (used as an indicator of low income) in the low pollution area the prevalence rates were about the same as among children whose parents had reached a higher education level. In the high pollution area the prevalences
959
HELENA RIBEIRO SOBRAL
960
Dust
particles
Org.
- Helena
Dn
-
I Air
quallty
-
Ivany
W.Sobral Bcmccorsi
/ 1988
I
standard
Osasco
...+.... Juquitlba
Year
Year
Fig. 1
Table 1. Prevalence rates of symptoms
Symvtom Cough with colds Apart from colds Most days Phlegm with colds Apart from colds Most days Congested chest + week/year Wheexing with colds Apart from colds Most days With shortness of breath Two or more episodes Required medicine Breathing abnormal interval After exercising Chest illnesses Out of activity for 3 days With more phlegm Before the age of 2 yean Hospital before 2 years old Other illnesses Measles Sinus trouble Bronchitis Asthma Pneumonia Whooping cough Ear infections Frequent ear infections Between the age of 0 and 2 Between the ages of 2 and 5 Over age 5 Ears drained Operation on tonsils or adenoids Asthma diagnosed by doctor Medicine for asthma Operation on chest Heart disease Allerav *SOI pollutant. tDust-particle pollutant.
Living place: Juquitiba (140 children) control area Pollutants: 13u/m’* (1981-82) 38~/rn’t ’ % positive
Osasco (108 children)
Tatuape (145 children)
79 p/m’* (1973-83). 73 plm’t % oositive
124p/m’* (1973-83) 127p/mst % oositivc
55.7 II.4 5.0 56.4 8.6 7.9 10.7 31.4 11.4 7.1 9.3 5.7 3.6 3.6 12.9
55.6 30.6 10.2 55.6 14.8 10.2 15.7 35.2 17.6 5.6 17.6 11.1 12.0 9.3 13.9
65.5 26.2 9.7 72.4 21.4 15.9 24. I 35.2 17.2 9.7 20.7 9.7 11.7 10.3 17.9
3.6 3.6 5.0 12.1
11.4 2.8 9.3 9.2
15.2 11.7 9.7 II.1
32. I 9.3 25.7 4.3 5.7 20.0 34.3
49.1 5.6 23.1 3.7 10.2 15.7 58.3
43.4 13.1 17.2 5.5 12.4 22. I 60.0
6.4 5.7 14.3 0.7 5.7 I.4
7.4 5.5 30.5 2.8 9.3 2.8 0.9 0 2.8 23.1
9.0 11.0 26.2 0.7 IL2 6.2 4.1 0.7 4.8 32.4
;::: 0 16.4
’
Respiratory diseases in children in So Paul0
i
\ \
961
HELENABBEIRO SOBRAL
962
\
\ I
c
\
‘
\
\
\ .\
a
L
\
Respiratory diseases in children in SBo Paulo
were much higher among those with illiterate parents. Since there were only few such cases the sample proved to be too small. This fact motivated additional investigation among children living in slums in the high pollution area. RESULTS
The results obtained from the survey are shown in Table 1. As a general trend, the prevalence rates of symptoms of respiratory diseases are higher in the areas with higher pollution levels. Tatuape showed higher prevalence rates for 26 out of 36 symptoms (72.2%). Osasco showed higher prevalence rates for seven symptoms (19.5%) and Juquitiba of only three symptoms (8.4%). The difference in the rates is greater for the symptoms that indicate the worst health conditions, for example, cough without cold, wheezing, phlegm on most days (4 or more days a week) for 3 months of the year, which are the symptoms adopted by doctors for diagnosing chronic bronchitis. Also asthma requiring medical care and treatment, heart problems and allergies showed much higher prevalence rates in the polluted areas, together with childhood diseases and ear and throat infections.
963
SOCIO-ECONOMIC
FACTORS
The study also tried to recognize social factors that could have influence upon respiratory diseases in children in order to identify more precisely the role of air pollution. Two social indicators were used; the number of persons per room of the house and the years of schooling of the parents. Houses with more than one person per room, including kitchen and bathroom, were considered to be occupied by low-income families. However, the prevalence rates of symptoms among the children living in those houses were not higher than those of the totality of the children. Parents who were illiterate were also considered to indicate low-income families. As already mentioned, the prevalence rates of symptoms aniong their children were similar to those of the totality of the children in Juquitiba (the area with negligible pollution), but they were much higher in the areas with median (Osasco) and high pollution (Tatuape) levels. In the Tatuape area, data obtained from the slum survey indicated prevalence rates many times higher than among the children in the government schools (see Table 2).
Table 2. Prevalence rates of symptoms Living place
Symptoms Cough with colds Apart from colds Most days Phlegm with colds . Apart from colds Most days Congested chest + week/year Wheezing with colds Apart from colds Most days With shortness of breath Two or + episodes Required medicine Breathing abnormal interval After exercising Chest illnesses Out of activity for 3 days With more phlegm Before the age of 2 years Hospital before 2 years old Other illnesses Measles Sinus trouble Bronchitis Asthma Pneumonia Whooping cough Ear infections Frequent ear infections Between the age of 0 and 2 Between the ages of 2 and 5 Over age 5 Ears drained Operation on tonsils or adenoid Asthma diagnosed by doctor Medicine for asthma Operation on chest Heart disease Allergy
Tatuape general (145 children) % positive answers
Tatuape shuns (21 children) % positive
65.5 21.9 9.1 72.4 21.4 15.9 24.1 40.8 Il.2 2:: 917 11.7 10.3 17.9
8.1 19.0 19.0 90.5 23.8 23.8 52.4 42.9 14.3 14.3 38. I 33.3 23.8 0 19.0
15.2 11.7 9.7 11.1
14.3 14.3 28.6 4.8
43.4 13.1 Il.2 5.5 12.4 22.1 60.0
16.2 19.0 42.9 19.0 14.3 33.3 52.4
4.1
4.8
2::: 0.7 Ii.2 6.2 4. I 0.7 4.0 32.4
3::; 1:: 14:3 9.5 0 9.5 33.3
HELENARIBEIROSOBRAL
964 CONCLUSIONS
In general, the results of this survey confirmed the hypothesis that air pollution affects the respiratory function of children living in mixed function districts of SHo Paul0 metropolitan area. Pollution levels seem to be the main aetiological factor. These may be further reinforced by low socio-economic conditions, mainly inadequate housing. These results corroborate studies done in other countries which also indicate higher prevalence rates of respiratory diseases in areas highly polluted by SO2 and dust particles. They also confirm the conclusions of Colley and Reid [3] in England and of Winkelstein [4] in the U.S.A. that indicated that poor people living in highly polluted regions are those whose health is most affected. The results obtained in the slum areas were similar to those of Girt [5] who showed that the high prevalence rates of chronic bronchitis in some sectors of Leeds were related not only to air pollution, but also to inadequate housing. This would be similar to the experience of high prevalence rates in the slums of Tatuape. Obviously many more studies are necessary in order really to evaluate the influence of air pollution on the development of respiratory diseases in the population of metropolitan area, but the results of this study show that the poorer people generally receive a heavier load of aetiological risk factors.’
Even though this survey aimed to study the effects of air pollution on children’s health it clearly showed that environmental and social problems are usually linked. Those findings are important in justifying geography as a social science since the relationship between human beings and environment may vary in terms of social class or community groups and populations must not be treated as uniform or homogeneous in the face of risks to health. REFERENCES 1. World Health Organization. Chronic respiratory diseases in children in relation to air pollution. Report on a Working Group. Long Term Programme in Environmental Pollution Control in Europe. Dusseldorf, 17-19 April, 1974. 2. Ferris B. G. Epidemiology standardization project. Am. Rev. Respirat. Dis. 118, 1978. 3. Colley J. R. T. and Reid D. D. Urban and social origins of childhood bronchitis in England and Wales. Br. med. J. ii, 213-217, 1970. 4. Winkelstein W. Utility or futility of ordinary mortality statistics in the study of air pollution effects. In Proceedings of the 6th Berkeley Symposium on Mathematical Statistics and Probabilify. University of California
Press, Berkeley, Calif., 1970. 5. Girt J. L. Simple chronic bronchitis and urban ecological structure. In Medical Geography: Techniques and Field Studies (Edited by McGlashan N. D.). Methuen, London, 1972.
Vol. 29. No. 8, pp. 959-964, 1989 Printed in Great Britain. All rights reserved
0277-9536/89f3.00 + 0.00
Copyright 0 1989Pergamon Press plc
AIR POLLUTION AND RESPIRATORY DISEASES CHILDREN IN SAO PAULO, BRAZIL
IN
HELENA RIBEIRO SOBRAL de Geografia, Pontificia Universidade Catolica de Slo Paulo, CP 7982, SHo Paulo, Brazil
Department0
Abstract-Air pollution in the huge conurbation of SHo Paulo, Brazil (13 million inhabitants) has been mapped from air quality monitoring stations. In three contrasted sample areas, children’s respiratory health parameters were collected to assess the roles of poverty and poor housing against those of air pollutton. Respiratory ill-health is clearly shown to vary with pollution levels and there is evidence that socio-economic conditions aggravate the problem. Key
words-air
pollution, child health, Sgo Paulo, Brazil, respiratory ill-health
INTRODUCTION The city of SZo Paulo has had a pre-eminent
role in
the Brazilian industrialization process since the first decades of this century and many districts with mixed functions have developed where industries and blue collar workers’ dwellings are found alongside each other. The State Pollution Control Agency (CETESB) has been monitoring air quality in-the metropolitan area only since 1973 but no previous studies have been done to verify the long term effects of air pollution on health. Yet respiratory diseases are known to be the second major cause of death in the city of SHo Paulo, a case unique in Brazil. The problem is even more serious because over 13,000,OOO people live in the metropolitan area. These facts motivated this study to ascertain whether there is a relationship between air pollution, which is quite severe in some areas, and the prevalence of respiratory diseases. METHODOLOGY
The first step was to map pollution by SO2 and by dust particles using the average of 11 yrs’ records for the metropolitan area, based on data collected by 39 CETESB monitoring stations. The mapping of CO and of photochemical pollutants was not possible because their levels are registered only at very few monitoring stations. The second step was to select three areas for study; one with a very low pollution level, Juquitiba, to be used as a control area; one with a medium pollution level, Osasco, just lower than the CETESB Air Quality Standard; and one with very high pollution all the year, Tatuape (Figs l-3). An epidemiological enquiry was carried out in each of these three among children 12 and 13 yr old. Longitudinal studies had been recommended by WHO [I] for areas where no previous investigation on the effects of air pollution on health had been done. Children at this age were chosen because among them the effects of occupational pollution and of smoking could be controlled and also at this age they are able adequately to answer the questionnaires.
The questionnaires used were developed by the Epidemiology Standardization Project [2] for children under 13 yr old and were applied in government schools located within 2 km distance from the monitoring stations in Tatuape (three schools), Osasco (three schools) and Juquitiba (one school only). All the children from this age group were listed and then a sample was selected with the size of the sample established from the formula: No.
n=
1+7
No.-1
where No. = $Q, P
P = prevalence rate of a disease expressed as a proportion of the total population, Q = complement (Q = 1 - P), TV= standard error of the prevalence P, ?p adopted was 5%, considered adequate for epidemiological studies and within the financial and personnel constraints of this project. Since the prevalence rates of many respiratory diseases were unknown, 50% was adopted as the rate that would require a larger number of questionnaires in order to minimize the chances of error. That meant that in each area at least 100 questionnaires had to be administered. In Juquitiba there were 140 children of this age group and they were all interviewed, in Tatuape 145 were interviewed and in Osasco 108. The survey was carried on in September, October and November in all three areas in order to avoid the influence of acute episodes of air pollution which often occur during winter and during spells of cold weather. In addition to these questionnaires another 21 were filled in by children of the same age group living in slums in Tatuape to find out whether social conditions in polluted areas had any influence on the prevalence rates of respiratory diseases. This was necessary because the analysis of the results showed that among children with illiterate parents (used as an indicator of low income) in the low pollution area the prevalence rates were about the same as among children whose parents had reached a higher education level. In the high pollution area the prevalences
959
HELENA RIBEIRO SOBRAL
960
Dust
particles
Org.
- Helena
Dn
-
I Air
quallty
-
Ivany
W.Sobral Bcmccorsi
/ 1988
I
standard
Osasco
...+.... Juquitlba
Year
Year
Fig. 1
Table 1. Prevalence rates of symptoms
Symvtom Cough with colds Apart from colds Most days Phlegm with colds Apart from colds Most days Congested chest + week/year Wheexing with colds Apart from colds Most days With shortness of breath Two or more episodes Required medicine Breathing abnormal interval After exercising Chest illnesses Out of activity for 3 days With more phlegm Before the age of 2 yean Hospital before 2 years old Other illnesses Measles Sinus trouble Bronchitis Asthma Pneumonia Whooping cough Ear infections Frequent ear infections Between the age of 0 and 2 Between the ages of 2 and 5 Over age 5 Ears drained Operation on tonsils or adenoids Asthma diagnosed by doctor Medicine for asthma Operation on chest Heart disease Allerav *SOI pollutant. tDust-particle pollutant.
Living place: Juquitiba (140 children) control area Pollutants: 13u/m’* (1981-82) 38~/rn’t ’ % positive
Osasco (108 children)
Tatuape (145 children)
79 p/m’* (1973-83). 73 plm’t % oositive
124p/m’* (1973-83) 127p/mst % oositivc
55.7 II.4 5.0 56.4 8.6 7.9 10.7 31.4 11.4 7.1 9.3 5.7 3.6 3.6 12.9
55.6 30.6 10.2 55.6 14.8 10.2 15.7 35.2 17.6 5.6 17.6 11.1 12.0 9.3 13.9
65.5 26.2 9.7 72.4 21.4 15.9 24. I 35.2 17.2 9.7 20.7 9.7 11.7 10.3 17.9
3.6 3.6 5.0 12.1
11.4 2.8 9.3 9.2
15.2 11.7 9.7 II.1
32. I 9.3 25.7 4.3 5.7 20.0 34.3
49.1 5.6 23.1 3.7 10.2 15.7 58.3
43.4 13.1 17.2 5.5 12.4 22. I 60.0
6.4 5.7 14.3 0.7 5.7 I.4
7.4 5.5 30.5 2.8 9.3 2.8 0.9 0 2.8 23.1
9.0 11.0 26.2 0.7 IL2 6.2 4.1 0.7 4.8 32.4
;::: 0 16.4
’
Respiratory diseases in children in So Paul0
i
\ \
961
HELENABBEIRO SOBRAL
962
\
\ I
c
\
‘
\
\
\ .\
a
L
\
Respiratory diseases in children in SBo Paulo
were much higher among those with illiterate parents. Since there were only few such cases the sample proved to be too small. This fact motivated additional investigation among children living in slums in the high pollution area. RESULTS
The results obtained from the survey are shown in Table 1. As a general trend, the prevalence rates of symptoms of respiratory diseases are higher in the areas with higher pollution levels. Tatuape showed higher prevalence rates for 26 out of 36 symptoms (72.2%). Osasco showed higher prevalence rates for seven symptoms (19.5%) and Juquitiba of only three symptoms (8.4%). The difference in the rates is greater for the symptoms that indicate the worst health conditions, for example, cough without cold, wheezing, phlegm on most days (4 or more days a week) for 3 months of the year, which are the symptoms adopted by doctors for diagnosing chronic bronchitis. Also asthma requiring medical care and treatment, heart problems and allergies showed much higher prevalence rates in the polluted areas, together with childhood diseases and ear and throat infections.
963
SOCIO-ECONOMIC
FACTORS
The study also tried to recognize social factors that could have influence upon respiratory diseases in children in order to identify more precisely the role of air pollution. Two social indicators were used; the number of persons per room of the house and the years of schooling of the parents. Houses with more than one person per room, including kitchen and bathroom, were considered to be occupied by low-income families. However, the prevalence rates of symptoms among the children living in those houses were not higher than those of the totality of the children. Parents who were illiterate were also considered to indicate low-income families. As already mentioned, the prevalence rates of symptoms aniong their children were similar to those of the totality of the children in Juquitiba (the area with negligible pollution), but they were much higher in the areas with median (Osasco) and high pollution (Tatuape) levels. In the Tatuape area, data obtained from the slum survey indicated prevalence rates many times higher than among the children in the government schools (see Table 2).
Table 2. Prevalence rates of symptoms Living place
Symptoms Cough with colds Apart from colds Most days Phlegm with colds . Apart from colds Most days Congested chest + week/year Wheezing with colds Apart from colds Most days With shortness of breath Two or + episodes Required medicine Breathing abnormal interval After exercising Chest illnesses Out of activity for 3 days With more phlegm Before the age of 2 years Hospital before 2 years old Other illnesses Measles Sinus trouble Bronchitis Asthma Pneumonia Whooping cough Ear infections Frequent ear infections Between the age of 0 and 2 Between the ages of 2 and 5 Over age 5 Ears drained Operation on tonsils or adenoid Asthma diagnosed by doctor Medicine for asthma Operation on chest Heart disease Allergy
Tatuape general (145 children) % positive answers
Tatuape shuns (21 children) % positive
65.5 21.9 9.1 72.4 21.4 15.9 24.1 40.8 Il.2 2:: 917 11.7 10.3 17.9
8.1 19.0 19.0 90.5 23.8 23.8 52.4 42.9 14.3 14.3 38. I 33.3 23.8 0 19.0
15.2 11.7 9.7 11.1
14.3 14.3 28.6 4.8
43.4 13.1 Il.2 5.5 12.4 22.1 60.0
16.2 19.0 42.9 19.0 14.3 33.3 52.4
4.1
4.8
2::: 0.7 Ii.2 6.2 4. I 0.7 4.0 32.4
3::; 1:: 14:3 9.5 0 9.5 33.3
HELENARIBEIROSOBRAL
964 CONCLUSIONS
In general, the results of this survey confirmed the hypothesis that air pollution affects the respiratory function of children living in mixed function districts of SHo Paul0 metropolitan area. Pollution levels seem to be the main aetiological factor. These may be further reinforced by low socio-economic conditions, mainly inadequate housing. These results corroborate studies done in other countries which also indicate higher prevalence rates of respiratory diseases in areas highly polluted by SO2 and dust particles. They also confirm the conclusions of Colley and Reid [3] in England and of Winkelstein [4] in the U.S.A. that indicated that poor people living in highly polluted regions are those whose health is most affected. The results obtained in the slum areas were similar to those of Girt [5] who showed that the high prevalence rates of chronic bronchitis in some sectors of Leeds were related not only to air pollution, but also to inadequate housing. This would be similar to the experience of high prevalence rates in the slums of Tatuape. Obviously many more studies are necessary in order really to evaluate the influence of air pollution on the development of respiratory diseases in the population of metropolitan area, but the results of this study show that the poorer people generally receive a heavier load of aetiological risk factors.’
Even though this survey aimed to study the effects of air pollution on children’s health it clearly showed that environmental and social problems are usually linked. Those findings are important in justifying geography as a social science since the relationship between human beings and environment may vary in terms of social class or community groups and populations must not be treated as uniform or homogeneous in the face of risks to health. REFERENCES 1. World Health Organization. Chronic respiratory diseases in children in relation to air pollution. Report on a Working Group. Long Term Programme in Environmental Pollution Control in Europe. Dusseldorf, 17-19 April, 1974. 2. Ferris B. G. Epidemiology standardization project. Am. Rev. Respirat. Dis. 118, 1978. 3. Colley J. R. T. and Reid D. D. Urban and social origins of childhood bronchitis in England and Wales. Br. med. J. ii, 213-217, 1970. 4. Winkelstein W. Utility or futility of ordinary mortality statistics in the study of air pollution effects. In Proceedings of the 6th Berkeley Symposium on Mathematical Statistics and Probabilify. University of California
Press, Berkeley, Calif., 1970. 5. Girt J. L. Simple chronic bronchitis and urban ecological structure. In Medical Geography: Techniques and Field Studies (Edited by McGlashan N. D.). Methuen, London, 1972.