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The associations between black smoke, sulphur diox- ide, nitrogen dioxide, carbon monoxide, surface ozone, and admissions for childhood asthma (ACA) in the ...
© by PSP Volume 15 – No 7. 2006

Fresenius Environmental Bulletin

ASSOCIATION BETWEEN AMBIENT AIR POLLUTION AND CHILDHOOD ASTHMA IN ATHENS, GREECE Athanasios G. Paliatsos1, Kostas N. Priftis2, Ioannis C. Ziomas3, Polytimi Panagiotopoulou-Gartagani4, Polyxeni Tapratzi-Potamianou5, Asimina Zachariadi-Xypolita4, Polyxeni Nicolaidou6 and Photini Saxoni-Papageorgiou5 1

General Department of Mathematics, Technological and Education Institute of Piraeus, 250 Thivon and P. Ralli Str., 12244 Athens, Greece 2 Department of Allergology-Pulmonology, Penteli Children’s Hospital, 15236 P. Penteli, Greece 3 School of Chemical Engineering, Department of Process Analysis and Plant Design, National Technical University of Athens, 15780 Athens, Greece 4 st 1 Paediatric Department, University of Athens, “Agia Sophia” Children’s Hospital, 11525 Athens, Greece 5 nd 2 Paediatric Department, University of Athens, “P & A Kyriakou” Children’s Hospital, 11527 Athens, Greece 6 rd 3 Department of Paediatrics, Attikon Hospital, University of Athens School of Medicine, 12462 Athens, Greece

SUMMARY The associations between black smoke, sulphur dioxide, nitrogen dioxide, carbon monoxide, surface ozone, and admissions for childhood asthma (ACA) in the Greater Athens Area (GAA) were evaluated. The mean monthly values of the mentioned air pollutants were obtained from the eight stations of the Athens air pollution-monitoring network for the period 1984-2000, whereas the corresponding monthly values of ACA were derived from the hospital registries of the three main Children’s Hospitals of Athens. The results of simple linear correlation showed that the monthly values of ACA depend mainly on black smoke, sulphur dioxide and carbon monoxide. The corresponding correlation coefficients were statistically significant for the 0-4 year age group, indicating an influence of primary air pollutants on childhood asthma. The application of stepwise regression analysis increased the linear correlation coefficient, and the corresponding amount of variance of childhood asthma, explained by ambient air pollution. The percentage was found to approach 43% for the 0-4 year age group and 50% for the 5-14 year age group. The results indicate a statistically significant influence of primary air pollutants on childhood asthma exacerbation.

KEYWORDS: Ambient air pollution, childhood asthma, stepwise regression analysis; Athens.

INTRODUCTION Athens faces air pollution problems, like the vast majority of big cities worldwide. The high population density, caused by the accumulation of industrial and commercial activities in and around the city, resulted in high

pollution levels during the last 35 years. Until the mid 80’s, the main air pollutants in the Greater Athens Area (GAA) were sulphur dioxide (SO2) and black smoke (BS), but photochemical pollution followed that from primary pollutants and resulted in the Athens photochemical smog. Air quality standards of the European Union (EU) and World Health Organisation (WHO) are frequently exceeded [1-8]. Greek authorities imposed the substitution of gasolinepowered vehicles with three-way catalyst vehicles. However, the decrease of the levels of primary air pollutants was accompanied by an increase of the levels of other air pollutants, such as nitrogen dioxide (NO2), and ozone (O3) associated with increased motor vehicle traffic in Athens basin [8]. The casual relationship between outdoor air pollution and children’s respiratory morbidity is well-established [9-20]. There is enough evidence that changes in trafficrelated pollutants have some influence on the worsening of asthmatic symptoms [11-19]. A pronounced seasonal variation of ACA in GAΑ has already been reported, rising during the cold damp period in the youngers, and peaking around May in olders [2123]. An increasing rate of asthma admissions among children in the GAA was also detected. The continuous increase during the first 15 years of the period 1978-2000 was followed by a deceleration and, finally, stabilization during the last few years. The mean annual increase in admission rate was 12.2% for 1978-1987, 4.7% for 1988-1993 and 0.6% for 1994-2000 [22]. In the present study, we evaluate the short-term effect of exposure to increased concentrations of BS, SO2, carbon monoxide (CO), NO2, and O3 in ambient air on child-

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hood asthma exacerbation, in terms of asthma admissions in the Children’s Hospitals of the city of Athens, Greece, during the 17-years period 1984-2000. MATERIALS AND METHODS Data regarding asthma admissions were obtained from the hospital registries of the three main Children’s Hospitals of Athens for the examining period (1984-2000), covering approximately 78-80% of the paediatric beds of GAA [21]. All children admitted with the diagnosis of “asthma”, “asthmatic bronchitis” or “wheezy bronchitis”, aged 014 years, living in the above-mentioned region, were included. They were classified into two age groups: 0-4 and 514 years. Monthly asthma admission rates, after adjusting for paediatric beds that are not accounted for (approximately 20-22% of total number), were expressed per 105 populations aged as the studied groups. The estimation of the population for each year of the study period was based upon the 1981 and 1991 national census. The whole studied period was split up into three shorter ones: 1984-1987, 19881993 and 1994-2000, according to the findings of the previous study [21]. The Greek Ministry of the Environment, Physical Planning and Public Works (MEPPPW) since summer of 1983 established a network in an attempt to measure - by automatic stations - CO, NO, NO2, SO2, and O3 concentrations in GAA. A detailed description of the MEPPPW network is found in a relevant publication [8]. The air pollution data used in this study were mean monthly concentrations averaged over all the available stations, for each air pollutant, in the MEPPPW network for the 17-years period 1984-2000. Data were analysed with SPSS 10.1 statistical software packages. The associations between the monthly ACA rates for each age group with air pollutants concentrations were investigated by Pearson’s correlation coefficients. Relations between the mean monthly ACA rates and the monthly mean values of ambient air pollutant concentrations were assessed, by using stepwise regression analysis-fitting models. The level of statistical significance was set at the 0.05.

RESULTS A total of 21,463 asthma admissions during the entire study period was registered, and 15,883 among the 04 years` age group [22]. The results of Pearson’s correlation coefficients between the ACA for each age group and the analyzed air pollutants under consideration are presented in Table 1. The correlations between the ACA and air pollutants are rather low, but statistically significant, with the exception of the 5-14 years age group, where the associations are almost all very poor. All of the coefficients for children aged 0-4 years are also rather low, with the highest values hardly reaching 0.785 (absolutely) (1994-2000). The coefficient for O3 is detected to be with a negative sign in all of the occasions. These findings mean that the percentage of the total variance of ACA explained by a single air pollutant can be up to 61.6%, for 1994-2000. On the contrary, for the period 1988-1993, the percentage of the total variance of ACA explained by a single air pollutant could be up to 59.3%. Generally, the values appear higher for the 04 years group than for the older children. For children aged 5-14 years, it appears (Table 1) that all coefficients are worse, with the greatest value hardly reaching 0.362 for 1994-2000. The percentage of the total variance of ACA explained by a single pollutant can be up to 13.1%, for the corresponding period. For the other first two shorter examined periods, the percentage appears to be up to 7.0% and 7.5%, respectively. The results of the application of stepwise regression analysis on monthly mean concentrations of the above mentioned air pollutants and monthly childhood asthma hospitalizations are summarized in Table 2. It is seen that the best results are achieved for the 514 years group in the period 1994-2000. The corresponding fitting model involving SO2 and CO concentrations explains an impressive percentage of the variance of ACA (49.3%, r = 0.702), and for the 0-4 years old group rather satisfactory percentages, 31.3% (1984-1987), 36.9% (19881993), and 43.4% (1994-2000).

TABLE 1 - Pearson’s correlation coefficients between the ACA and air pollutants, for the period 1984-2000 (statistically significant values at the 95% confidence level are presented in bold). Period

Age group

1984-1987

0-4 5-14 0-4 5-14 0-4 5-14

1988-1993 1994-2000

BS (µg/m3) 0.471 0.043 0.444 0.113 0.381 0.058

SO2 (µg/m3) 0.308 0.001 0.480 0.067 0.312 0.288

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CO (mg/m3) 0.438 0.139 0.546 0.175 0.624 0.159

NO2 (µg/m3) 0.172 0.264 0.118 0.082 0.123 0.362

O3 (µg/m3)

-0.770 -0.273 -0.785 -0.188

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TABLE 2 - Relations between the ACA and the monthly mean values of air pollutants, by using stepwise regression analysis-fitting models. Period 1984-1987

Age group Model 0-4 ACA = 0.337BS + 0.8NO2 – 41.372 5-14 -------------1988-1993 0-4 ACA = 15.503CO - 0.569NO2 + 35.807 5-14 -------------1994-2000 0-4 ACA = 27.995CO - 0.556BS + 19.086 5-14 ACA = -0.169SO2 + 1.063CO + 1999.184 (*): Standard Error of the Estimate in hospitalizations for childhood asthma per month

DISCUSSION AND CONCLUSIONS This 17-years retrospective study showed an association between ambient air pollution and ACA in Athens, especially concerning children aged 0-4 years, during the most recent years. SO2 and CO concentration levels appear to be better related with the monthly ACA of older children for the period 1994-2000, whereas analysis of O3 data revealed a negative relationship, most probably because of the children’s summer holidays. A growing body of evidence is showing the association between particulate, as well as photochemical air pollutants and hospitalizations for acute asthma, especially in children. However, there is an inconsistency of the results of the miscellaneous studies, and a variety of patterns of this association has been reported [9-17]. It appears to be extremely difficult to single out an air pollutant or a combination of pollutants, which are specifically responsible for the short-term effects on asthmatics in the pragmatic studies. Several factors have been implicated in that inconsistency, such as the different geomorphologic conditions in the cities, the differences in spatial distribution of air pollution monitoring networks and the different prevalence of the “susceptible” population [17, 22]. According to the results of the application of stepwise regression analysis, the SO2 concentrations are clearly related to asthma admissions, especially in the 5-14 years aged group for the period 1994-2000. Significant correlation coefficients were also detected in the 0-4 years age group for the three examined sub-periods. These findings are in accordance with the results of APHEA 2 study, and other studies as well [17, 24-26]. Furthermore, positive relations between SO2, CO and NO2 concentrations at comparatively low levels and children’s asthma hospitalizations by using bi-directional case-crossover analyses was recently reported in Toronto for a period between 1981 and 1993 [26]. In this study, although a positive relation with CO concentrations was also observed, there was no significant dependence of monthly childhood asthma hospitalizations on NO2. The most striking of our results was the negative relation between O3 concentrations and ACA, since the main body of the relevant evidence reports the opposite [11, 12,

r2 0.313 -----0.369 -----0.434 0.493

SEE (*) 16.059 -----17.526 -----15.832 1.465

14, 17, 26]. Obviously, this observation should not be considered as a causal effect, but as an epiphenomenon. Ozone, due to its photochemical nature, reveals a strong seasonal dependence following the variation of solar insolation levels. A strong seasonal variation of ozone concentrations in GAA has been observed with a characteristic summer maximum, when children in Greece are on summer holidays [2, 7]. In a previous study looking at the seasonal variation of ACA, we detected a strong minimum of asthma hospitalizations in July and August in both age groups with a repetitive pattern [21-22]. According to the measurements of the MEPPPW network, during the last 20 years, the main air pollution problem in the GAA is secondary formation of photochemical air pollutants, such as surface ozone, a product of the occurrence of intense solar insolation and increased emissions of ozone precursors, which happens mainly by that period [3-4, 7]. The amelioration of the air pollution situation with respect to BS, SO2, CO, NO2 and O3 concentrations may be attributed to the findings of previous studies [8, 27]. The reduction of BS and SO2 concentration levels is attributed to the various government measures and regulations concerning controls and restrictions in oil consumption, having been gradually applied to all pollution sources, along with the oil quality improvement ever since 1986 [29-32]. In spite of these decreasing trends, the levels of BS concentrations in the centre of Athens remain, for the most part of the examined period, above the EU limit values [8, 27, 32]. According to the requirements of the EU directive 80/779, only 2% of smoke concentrations can exceed 250 µg/m3 [34]. However, violations of the EU limits were on the decline during the examined period [8]. Annual percentages of 8-h CO concentrations being higher than the WHO long-term target (10 mg/m3) [8] during almost the whole examined period, were mainly observed during the fall seasons, and partly be attributable to an increase of surface inversions [32]. Also in this case, decline during the greater part of the examined period can be attributed to the renewal of the vehicle fleet [28, 32-33], and the relatively high percentages during 1997-2000 to the low rate of catalysts’ replacement [28]. The annual 98% percentiles of hourly NO2 concentrations that are higher than the corresponding national limit

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(200 µg/m3) for the period 1984-2000, reveal a generally declining tendency since 1992 [8]. Increases were mainly observed during the spring seasons, and can be partly attributed to the increased number of photochemical pollution episodes [2, 8]. Reductions observed can be attributed to the renewal of the vehicle fleet [28, 32-33]. Finally, the annual percentages of 8-h average (12:0020:00 LST) surface ozone concentrations being higher than the standard for human health protection set by the EU, which is also a WHO guideline (110 µg/m3) [35-36], at least for the period 1994-2000, reveals a slightly declining tendency [7]. This rather slightly rising tendency in intensity of violations - mainly observed during the warm period of the year (April - September) - can be partly attributed to the high photochemical ozone production, because of the high solar insolation during the daytime period. These findings are in accordance with that observed by others as well [2, 7]. The main limitation of this study was the fact that admission rates were given on a monthly basis and not on a weekly or daily one. In that way, some short-term effect of air pollution may be lost. The very prolonged study period (17 years) eliminates the weakness and allows possible detection of repeated specific conditions affecting asthma symptoms. In conclusion, these results indicate that ambient air pollution influences the hospitalization rates for childhood asthma in Athens, Greece, during the period 1984-2000. The main dependence appears to be on BS, SO2 and CO. Other factors are implicating the degree of air pollutant influence. Further studies are needed to elucidate the role of air pollutants on childhood asthma.

REFERENCES [1]

[2]

[3]

[4]

[5]

Mantis, H.T., Repapis, C.C., Zerefos, C.S. and Ziomas, I.C. (1992) Assessment of the potential of photochemical air pollution in Athens: a comparison of emissions of air pollution levels in Athens with those in Los Angeles. J. Appl. Meteor., 31, 1467-1476. Ziomas, I.C., Suppan, P., Rappengluch, B., Balis, D., Tzoumaka, P., Melas, D., Papayannis, A., Fabian, P. and Zerefos, C.S. (1995) A Contribution to the study of photochemical smog in the greater Athens area. Beitr. Phys. Atmosph., 68, 198-203. Ziomas, I.C., Melas, D., Zerefos, C.S., Bais, A.F and Paliatsos, A. (1995) Forecasting peak pollutant levels using meteorological variables. Atmosph. Environ., 29, 3703-3711. Ziomas, I.C., Melas, D., Zerefos, C.S., Bais, A.F and Paliatsos, A. (1995) On the relationship between peak ozone levels and meteorological variables. Fresen. Environ. Bull., 4, 53-58. Ziomas, I.C. (1998) The Mediterranean campaign of photochemical tracers-transport the chemical evolution (MEDCAPHOT-TRACE): an outline. Atmosph. Environ., 32, 2045-2053.

617

[6]

Ziomas, I.C., Tzoumaka, P., Balis, D., Tzoumaka, P., Melas, D., Zerefos, C.S. and Klemm, O. (1998) Ozone episodes in Athens, Greece. A modelling approach using data from MEDCAPHOT-TRACE. Atmosph. Environ., 32, 2313-2321.

[7]

Kalabokas, P.D., Viras, L.G., Repapis, C.C. and Bartzis, J.G. (1999) Analysis of the 11-year record (1987-1997) of air pollution measurements in Athens, Greece. Part II: Photochemical pollutants. Global Nest: the Int. J., 1, 169-176.

[8]

Paliatsos, A.G., Kaldellis, J.K., Koronakis, P.S. and Garofalakis, J.E. (2002) Fifteen year air quality trends associated with the vehicle traffic in Athens, Greece. Fresen. Environ. Bull., 11, 12b, 1119-1126.

[9]

Lipfert, F.W. (1993) A critical review of studies of the association between demands for hospital services and air pollution. Environ. Health Perspect., 101, 216-222.

[10] D’Amato, G., Liccardi, G., D’Amato, M. and Cazzola, M. (2002) Outdoor air pollution, meteorological changes and allergic bronchial asthma. Eur. Respir. J., 20, 736-776. [11] Anderson, H.R., Ponce de Leon Bland, J.M., Bower, J.S., Emberlin, J. and Strachan, D.P. (1998) Air pollution, pollens, and daily admissions in London 1987-92. Thorax, 53, 842-848. [12] White, M.C., Etzel, R.A., Wilcox, W.D. and Lloyd, C. (1994) Exacerbations in childhood asthma and ozone pollution in Atlanta. Environ. Res., 65, 56-68. [13] Romieu, L., Maneses, F., Sienra-Monge, J.J.L., Huerta, J., Velasko, S.R., White, M.C., Etzel, R.A. and Hernadez-Avila, M. (1995) Effects of urban air pollutants on emergency visits for childhood asthma in Mexico City. Am. J. Epidemiol., 141(6), 546-553. [14] Sunyer, J., Spix, C., Quenel, P., Ponce-de-Leon, A., Barumandzadeh, T., Touloumi, G., Bacharova, L., Wojtyniak, B., Vonk, J., Bisanti, L., Schwartz, J. and Katsoyyanni, K. (1997) Urban air pollution and emergency admissions for asthma in four European cities: The APHEA project. Thorax, 52(9), 760765. [15] Tenias, J.M., Ballester, F. and Rivera, M.L. (1998) Association between hospital emergency visits for asthma and air pollution in Valencia, Spain. Occupational and Environmental Medicine, 55(8), 541-547. [16] Schwartz, J. (2004) Air pollution and children’s health. Pediatrics, 113(4), 1037-1043. [17] Fusco, D., Forastiere, F., Michelozzi, P., Spadea, T., Ostro, B., Arcà, M. and Perucci, C.A. (2001) Air pollution and hospital admissions for respiratory conditions in Rome, Italy. Eur. Respir. J., 17, 1143-1150. [18] Migliaretti, G. and Cavallo, F. (2004) Urban air pollution and asthma in children. Pediatr. Pulmonol., 38, 3, 198-203. [19] Jalaludin, B.B., O’Toole, B.I. and Leeder, S.R. (2004) Acute effects of urban ambient air pollution on respiratory symptoms, asthma medication use, and doctor visits for asthma in a cohort of Austalian children. Environ. Res., 95, 32-42. [20] Bartzokas, A., Kassomenos, P., Petrakis, M. and Celessides, C. (2004) The effect of meteorological and pollution parameters on the frequency of hospital admissions for cardiovascular and respiratory problems in Athens. Indoor and Built Environ., 13, 271-275.

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[21] Priftis, K., Anagnostakis, J., Harokopos, E., Orfanou, I., Petraki, M. and Saxoni-Papageorgiou, P. (1993) Time trends and seasonal variation in hospital admissions for childhood asthma in the Athens region of Greece: 1978-88. Thorax, 48, 1168-1169. [22] Priftis, K., Panagiotopoulou-Gartagani, P., Tapratzi-Potamianou, P., Zachariadi-Xypolita, A., Sagriotis, A. and SaxoniPapageorgiou, P. (2005) Hospitalizations for childhood asthma in Athens – Greece from 1978 to 2000. Pediatr. Allergy Immunol., 16, 4, 82-85.

[35] World Health Organisation (WHO) (1987) Air Quality Guidelines for Europe, WHO Reg. Publ. Eur. Ser. No. 23, WHO, Copenhagen. [36] World Health Organisation (WHO) (2000) Air Quality Guidelines, 2nd Edition, WHO Regional Publication for Europe, Copenhagen, Denmark.

[23] Priftis, K.N., Paliatsos, A.G., Panagiotopoulou-Gartagani, P., Tapratzi-Potamianou, P., Zachariadi-Xypolita, A., Nicolaidou, P. and Saxoni-Papageorgiou, P. (2006) Association of weather conditions with childhood admissions for wheezy bronchitis or asthma in Athens. Respiration (in press). [24] Sunyer, J., Atkinson, R., Ballester, F., Le Tertre, A., Ayres, J.G., Forastiere, F., Forsberg, B., Vonk, J.M., Bisanti, L., Anderson, R.H., Schwartz, J. and Katsouyianni, K. (2003) Respiratory effect of sulphur dioxide: a hierarchical multicity analysis in the APHEA 2 study. Occup. Environ. Med., 60, e2. [25] Mortimer, K.M., Neas, L.M., Dockery, D.W., Redline, S. and Tager, I.B. (2002) The effect of air pollution on inner-city children with asthma. Eur. Respir. J., 19, 699-705. [26] Lin, M., Chen, Y., Burnett, R.T., Villeneuve, P.J. and Krewski, D. (2003) Effect of short-term exposure to gaseous pollution on asthma hospitalization in children: a bi-directional casecrossover analysis. J. Epidemiol. Commun. H., 57, 50-55. [27] Kalabokas, P.D., Viras, L.G., Repapis, C.C. and Bartzis, J.G. (1999) Analysis of the 11-year record (1987-1997) of air pollution measurements in Athens, Greece. Part I: Primary air pollutants. Global Nest: the Int. J., 1, 157-167. [28] Paliatsos, A.G., Kaldellis, J.K. and Viras, L.G. (2001) The management of devaluated autocats and air quality variation in Athens. In: Proceedings of the Seventh International Conference on “Harmonization within Atmospheric Dispersion Modeling for Regulatory Purposes”, Belgirate, Italy, 474-478. [29] Paliatsos, A.G., Viras, L.G., Ziomas, I.C. and Amanatidis, G.T. (1996) Routine air pollution measurements in Athens: rationalization of the monitoring network using spatial correlation analysis. Fresen. Environ. Bull., 5, 436-441. [30] Paliatsos, A.G. and Amanatidis, G.T. (1994) Smoke concentrations in Athens, Greece: trends and strong episodes, 19841991. Sci. Total Environ., 144, 137-144. [31] Paliatsos, A.G. (1998) The seasonal and diurnal variation of sulphur dioxide in Greater Athens Area, Greece. Fresen. Environ. Bul., 7, 539-550. [32] Paliatsos, A.G., Angelopoulos, K.C., Coucouletsos, C., Karamolengos, M. and Stamatakos, D.P. (2000) Fifteen years of regular smoke measurements in Greater Athens Area, Greece. Fresen. Environ. Bul., 9, 515-522. [33] Kaldellis, J.K., Charalambidis, P. and Konstandinidis, P. (2000) Feasibility study concerning the future of devaluated autocats, social environmental cost included. In: Proceedings of Int. Conf. “Protection and Restoration of the Environment V”, Thassos, Greece, Vol. 2, 879-886. [34] EU (1980) Directive on air quality limit values for sulphur dioxide and particulates (Directive 80/779).

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Received: September 28, 2005 Accepted: December 07, 2005

CORRESPONDING AUTHOR Athanasios G. Paliatsos General Department of Mathematics Technological and Education Institute of Piraeus 250 Thivon and P. Ralli Str. 12244 Athens Greece e-mail: [email protected] FEB/ Vol 15/ No 7/ 2006 – pages 614 - 618