Abstract
Atmospheric fine particles (PM2.5) have an adverse effect not only on human health such as increase in the death rate, but also on quality of life (QOL) by deteriorating level of visibility and spoiling scenery. In addition, negative impact on forestry ecosystem and decrease in harvest of crops as a result of influence given by PM2.5 are also of a concern. On the other hand, PM2.5 also gives influence on global climate system directly or indirectly because they change the radiation conditions in the atmosphere, where degree of such influence varies depending on how PM2.5 is chemically composed and distributed in a three dimensional manner. Because of this variance, it is difficult to have accurate evaluation of the influence given by PM2.5. It is suspected that synergetic effect caused by gaseous pollutants and fine particulate matter is driving the influence given by PM2.5, and understanding such actual status in an accurate manner is of great urgency and importance. In Japan, environmental standard of PM2.5 was established in September, 2010. To understand the background of this standard, the information of PM2.5 epidemiological study and processes in setting the PM2.5 environmental standard in the US is helpful. PM2.5 is not composed of single matter, and is emitted in both anthropogenic and natural manners, thus the mechanism of PM2.5 generation is widely ranged. In order to conduct effective emission control of PM2.5, it is important to identify the linkage between its emission source and environmental concentration, where measurement, monitoring and componential analysis of atmospheric environment containing PM2.5 are required. Under these context, future challenges in measurement, monitoring and componential analysis of PM2.5 are addressed in this review by explaining overseas trends of PM2.5 including those of U.S. and Europe, and how discussions on this issue have developed in Japan.
