FY2009 Annual Report of Environmental Health Surveillance for Air Pollution

The Ministry of the Environment (MOE) has been implementing environmental health surveillance for air pollution every year since 1996 in response to the amendment of the Pollution-related Health Damage Compensation Law (amendment to the Law Concerning Special Measures for the Relief of Pollution-related Health Damage) of 1988. It aims to regularly and continuously observe the correlation between the health conditions of local populations and air pollution, and to take measures as necessary.
[Overview of the FY2009 Surveillance Result]
The FY2009 surveillance targeted 3-year-old children (hereinafter, "3-year-old survey") and first-year primary school children (hereinafter, "6-year-old survey") as in previous years. A cross-sectional analysis was performed using the results of these surveys (FY2009), and a longitudinal analysis was performed using the integrated results of 3-year-old surveys from FY1996 to FY2009 and 6-year-old surveys from FY2004 to FY2009. Additionally, a follow-up analysis was performed on 6-year-old respondents who also responded to the 3-year-old survey conducted in FY2005 and FY2006.
The 3-year-old survey targeted approximately 90,000 3-year-old children in 38 regions throughout Japan (73,000 respondents), and the 6-year-old survey targeted approximately 89,000 6-year-old children in 38 regions throughout Japan (73,000 respondents).
Among the respiratory symptoms surveyed, the results of analyses relating to asthma were as follows.
In terms of an examination of odds ratios, the 3-year-old survey showed a significant correlation between air pollution (SPM) and asthma for the first time last year, but not this year. On the other hand, the 6-year-old survey showed no significant correlation between air pollution (SPM) and asthma last year, but showed a significant correlation this year (odds ratio 1.08; 95% confidence interval [1.00 - 1.16]). In regard to air pollutants other than SPM, neither the 3-year-old survey nor 6-year-old survey showed a significant correlation between these air pollutants and asthma again this year. Meanwhile, the exposure assessment revealed a general downward trend in air pollution (SPM), and the exposure assessment and health survey combined showed no clear trend between high asthma prevalence and high air pollutant concentrations, neither in the analysis of respiratory symptom prevalence at each background concentration level for each subject group, nor in the correlation between average background concentration and respiratory symptom prevalence in each survey area for each subject group.
With respect to symptoms other than asthma, the frequency of catching a cold (more than five times) tended to increase with higher air pollutant concentrations, but the same trend was not observed with cases of wheezing (both associated and not associated with a cold).
[Future Issues]
The correlation between SPM and asthma as observed in the 3-year-old survey and 6-year-old survey cannot be seen as indicating certain trends yet, but it will continue to be observed carefully, also in consideration of regional characteristics.
In response to the environmental quality standards for PM2.5 that were promulgated in September 2009, a continuous surveillance system is currently being developed, so based on the progress of its development, studies of PM2.5 will be conducted as required, also in reference to SPM.
Additionally, in recent years, photochemical oxidant warnings are being issued mainly in western Japan, and there are growing concerns about the influence of photochemical oxidants on people's health. As many foreign countries are revising their standards for photochemical oxidants, future developments will continue to be closely monitored.
Further studies will also be made in reference to the "Result of the Epidemiological Study of the Health Effects of Localized Air Pollution" announced in May 2011.

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