2011 Volume 46 Issue 2 Pages 70-76
Environmental Air Quality Standard or its guideline value for PM2.5 has been revised or newly set in US, WHO and Japan since 2006 based on epidemiological and toxicological review. Epidemiologic evidence indicates the causal relationship between PM2.5 exposure and effects on cardiovascular and respiratory systems. It is suggested that exposure to PM2.5 around 10-15μg/m3 can cause increased mortality from cardiovascular diseases by exposure-response relationship analysis obtained from prospective cohort studies, but such studies were conducted in the Western countries. Effects of short-term exposure to PM2.5 on total and cardiovascular deaths were also confirmed by multi-city studies with time-series/case-crossover analysis in North America. Contradictory to these results, similar results were not obtained in studies conducted in Japan. Since it is well known that disease pattern as well as distribution pattern of cardiovascular risk factors are quite different in Japan from the Westerns, new epidemiological studies should be done in Japan. Comparability of potential confounders is important for selection of study regions. Another topic for PM2.5 epidemiology is lung function development of children who are a susceptible population. All these studies should be done carefully, especially to include regions in Japan where PM2.5 concentration varies from background to high level.
