Review of atmospheric metallic elements in Asia during 2000-2004

Metallic element transfer through the atmosphere is a significant part of the biogeochemical cycle of these elements. Natural and anthropogenic were two processes which can increase heavy metal concentrations in the atmosphere. Atmospheric particulates, especially secondary anthropogenic fine particles (PM2.5), have been influence human health. Generally speaking, the total daily mortality increases by approximately 1% for every 10 mu g m(-3) increase in PM10 concentration (Lippmann, 1998). This is why the PM10 and PM2.5 measurements are included in the US ambient air quality standards (US-EPA, 1987 for PM10; 1996 for PM2.5) (Querol et al., 2001). In recent years, since the great efforts made by Taiwan government towards the reduction Of O-3 and PM10 concentrations by controlling the emission rates of local pollutants sources, the frequency of exceeded PSI has gradually decrease the value of 4.9% in 1999 (Taiwan EPA, 2000). Urban populations are exposed to metals in suspended particles and these are often well above natural background levels owing to anthropogenic processes (Espinosa et al., 2002). This results in elevated metal concentrations that can pose an important risk to human health. Understanding emissions from traffic includes identification of the sources, which is also crucial for designing control measures. Road traffic involves numerous potential sources of metals, combustion products from fuel and oil, wear products from tires, brake linings, bearings, coach and road construction materials, and re-suspension of soil and road dust. The different sample collection devices, pretreatment and analysis methods were discussed in this study. The purpose of this study arranges the atmospheric metallic elements investigations in Asia regions. The data obtained here can also help to understand the sources, concentration, phase distribution and health impact of atmospheric metallic elements in Asian countries. (c) 2005 Elsevier Ltd. All rights reserved.