Long-Term Variations of Airborne Cadmium (Cd) Concentrations in Major Urban Areas of Korea between 1991 and 2010

Abstract

The long-term (1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010) monitoring data for cadmium (Cd) collected from seven major cities in Korea were evaluated to assess spatial-temporal trends in urban areas and help improve air quality control. The results show that the level of Cd pollution in the different cities, as distinguished by industrial activity, was the highest in Ulsan (9.21 ± 6.29 ng/m 3 ) and Incheon (6.25 ± 6.05 ng/m 3 ). During the study period, Cd concentrations showed significant reductions in all monitoring cities, especially in the more industrialized ones (e.g., a nearly six-fold reduction in Ulsan over 13 years), while in other areas this reduction was more moderate (about 1.7-fold). In addition, Cd concentrations generally peaked in the winter, with the exception of the more industrialized areas. Although Cd levels in Ulsan and Incheon exceeded the general guidelines of 5 ng/m 3 (e.g., those of the US EPA) until recently (e.g., 2004), its values in most urban areas in Korea have been continuously decreasing over the 20-year period examined in this work. Therefore, greater efforts are necessary to more effectively reduce Cd released from the prominent source activities in the urban environments.

Comparative assessment of heavy metals changes in the ambient air of two different zones of Tabriz City, Iran

“…The major sources of lead in the atmosphere of the cities are the combustion of leaded gasoline in vehicles and airplanes as well as fume of factories. Fortunately, currently by replacing gasoline containing lead with leadfree gasoline, its level has decreased in many cities around the world including Iran (Saha and Kim, 2013;Sarrafpour et al, 2007). Although no previous information is available about the levels of lead in Tabriz air, in this research the concentration of lead in air of Tabriz was recorded to be below the acceptable standards, according to Table 1, though this value is still high.…”