Low-Level Air Pollution and Upper Respiratory Infections in Children Jouru J. K Jaakkol MD, Mikkco Paunio, MD, Mantt Vutanen, MD, and Oh1 P. Heinonen, MD, DSc
Intodin Several studies in the 1960s showed that children living in areas with sulfur dioxide (SO2) and particulate levels above 100 ,ug/m3 had an increased occurrence of respiratory symptoms, upper and lower respiratory tract illnesses, and lower levels of pulmonary function than children living in less polluted areas.5 The evidence is controversial on the effects of air pollution at levels lower than 100 1±g/ m3.69 However, a recent study from Israel reported a significantly higher prevalence of respiratory symptoms and conditions in second- and fifth-grade children living in an area of Israel with an annual average of only 30 P,glm3 SO2 than in children of a less polluted area.9 We evaluated the effect of low-level air pollution by comparing the frequency of upper respiratory infections in infants and preschool children in Oulu (polluted city), the northernmost industrial city in Finland, and in two cities with little industrial ambient air pollution, Vaasa (southem reference city) and Rovaniemi (northern reference city); see Figure 1.
.
I
NORWAY
U.S.S.R
RIovaniemi
Arctic -
Circle
Oulu
S (polluted city)
5aasa
FINLAND
Helsinki
FIGURE 1-Location of Oulu, the Polluted Clty, and Vaasa and Rovanlemi, the Refer-
ence Cffm
Methds Oulu (population 96 000) is located the Baltic coast. Vaasa (coastal, population 54 000) and Rovaniemi (inland, population 31 000) are the closest southem and northem cities with an approximately similar level of urbanization but with little industrial air pollution in the downtown areas. Four main pollution sources encircle the town center of Oulu (Figure 2). A sulfite cellulose pulp mill including a power station, northwest of the center, is the biggest source of sulfur dioxide (SO2) pollution (2500 tonnes/y). The main source of nitrogen oxides (NO.), a chemical plant producing acids and fertilizers, lies to the northeast. To the southwest a sulfate cellulose pulp mill, which is a source of hydrogen sulfide (H2S) and methyl mercaptan (CH3SH), causes odor disturbance. The heating plant of Oulu on
University Hospital, in the southeast, is an important source of SO2 and particulates. All cities monitor S02 and particulate concentrations. In the polluted city, H2S and NO, concentrations have also been measured since 1983. The measured concentrations from 1982 to 1984 are summarized in Table 1. Jouni J. K Jaakkola, Mikko Paunio, and Oli P. Heinonen are with the Department of Public Health, University ofHelsinki. Martti Virtanen is with Jorvi Hospital, Espoo, Finland. Requests for reprints should be sent to Jouni J. K. Jaakkola, Department of Public Health, University of Helsinki, Ki/Ko 302, Otakaari 4A, SF-02150 Espoo, Finland (Fax: +358-0451 3611). This paper was submitted to the journal February 6, 1990, and accepted with revisions April 2, 1991.
August 1991, Vol. 81, No. 8
Public Health Briefs
Although the long-term mean levels of SO2 were only slightly greater in the polluted city than in the reference cities, there were more frequent periods of shortterm, high-level exposure to SO2 due to downtown industrial sources. The population of the polluted city was exposed to
considerably greater levels of H2S, CH3SH, and other malodorous sulfur compounds and nitrogen oxides. The polluted city was divided into areas of more and less pollution according to the dispersal models of SO2 made by the Finnish Meteorologic Institute. The more
polluted area included all postal districts with an annual mean concentration of S02 >15 ,ug/m3 and two postal districts with NO, produced by the chemical plant but with SO2 concentrations
Intodin Several studies in the 1960s showed that children living in areas with sulfur dioxide (SO2) and particulate levels above 100 ,ug/m3 had an increased occurrence of respiratory symptoms, upper and lower respiratory tract illnesses, and lower levels of pulmonary function than children living in less polluted areas.5 The evidence is controversial on the effects of air pollution at levels lower than 100 1±g/ m3.69 However, a recent study from Israel reported a significantly higher prevalence of respiratory symptoms and conditions in second- and fifth-grade children living in an area of Israel with an annual average of only 30 P,glm3 SO2 than in children of a less polluted area.9 We evaluated the effect of low-level air pollution by comparing the frequency of upper respiratory infections in infants and preschool children in Oulu (polluted city), the northernmost industrial city in Finland, and in two cities with little industrial ambient air pollution, Vaasa (southem reference city) and Rovaniemi (northern reference city); see Figure 1.
.
I
NORWAY
U.S.S.R
RIovaniemi
Arctic -
Circle
Oulu
S (polluted city)
5aasa
FINLAND
Helsinki
FIGURE 1-Location of Oulu, the Polluted Clty, and Vaasa and Rovanlemi, the Refer-
ence Cffm
Methds Oulu (population 96 000) is located the Baltic coast. Vaasa (coastal, population 54 000) and Rovaniemi (inland, population 31 000) are the closest southem and northem cities with an approximately similar level of urbanization but with little industrial air pollution in the downtown areas. Four main pollution sources encircle the town center of Oulu (Figure 2). A sulfite cellulose pulp mill including a power station, northwest of the center, is the biggest source of sulfur dioxide (SO2) pollution (2500 tonnes/y). The main source of nitrogen oxides (NO.), a chemical plant producing acids and fertilizers, lies to the northeast. To the southwest a sulfate cellulose pulp mill, which is a source of hydrogen sulfide (H2S) and methyl mercaptan (CH3SH), causes odor disturbance. The heating plant of Oulu on
University Hospital, in the southeast, is an important source of SO2 and particulates. All cities monitor S02 and particulate concentrations. In the polluted city, H2S and NO, concentrations have also been measured since 1983. The measured concentrations from 1982 to 1984 are summarized in Table 1. Jouni J. K Jaakkola, Mikko Paunio, and Oli P. Heinonen are with the Department of Public Health, University ofHelsinki. Martti Virtanen is with Jorvi Hospital, Espoo, Finland. Requests for reprints should be sent to Jouni J. K. Jaakkola, Department of Public Health, University of Helsinki, Ki/Ko 302, Otakaari 4A, SF-02150 Espoo, Finland (Fax: +358-0451 3611). This paper was submitted to the journal February 6, 1990, and accepted with revisions April 2, 1991.
August 1991, Vol. 81, No. 8
Public Health Briefs
Although the long-term mean levels of SO2 were only slightly greater in the polluted city than in the reference cities, there were more frequent periods of shortterm, high-level exposure to SO2 due to downtown industrial sources. The population of the polluted city was exposed to
considerably greater levels of H2S, CH3SH, and other malodorous sulfur compounds and nitrogen oxides. The polluted city was divided into areas of more and less pollution according to the dispersal models of SO2 made by the Finnish Meteorologic Institute. The more
polluted area included all postal districts with an annual mean concentration of S02 >15 ,ug/m3 and two postal districts with NO, produced by the chemical plant but with SO2 concentrations
