November 14, 2003
In compliance with the Air Pollution Control Law, local governments have been monitoring hazardous air pollutants in the atmosphere since FY 1997. Results of these monitoring surveys have been compiled together with those monitored by the Ministry of the Environment. The results are as follows.
1. | Substances for which environmental quality standard (EQSs) are established |
Measurements of benzene exceeded the EQS at 8.3 % of monitoring points, which was improved from 18.2 % in FY2001, and the average concentration level also showed a declining trend. Other substances met the EQSs at almost all monitoring points.
Substance | Number of monitoring points |
Ratio of monitoring points exceeding EQS(%) |
Average concentration (microgram/m3) |
Range of concentration (microgram/m3) |
Benzene | 409 | 8.3 | 2.0 | 0.49 - 5.7 |
Trichloroethylene | 341 | 0 | 1.0 | 0.0012 - 70 |
Tetrachloroethylene | 355 | 0 | 0.43 | 0.029 - 7.6 |
Dichloromethane | 351 | 0.3 | 2.9 | 0.16 - 190 |
2. | Substances for which guideline values are established as a guide to reduce health risks resulting from hazardous air pollutants in the air |
Measurements of nickel compounds exceeded the guideline value at 2.9 % of monitoring points, however, the average concentration level showed a declining trend.
Measurements of acrylonitrile, vinyl chloride monomer, mercury and its compounds met the guideline values at all monitoring points.
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* | Environmental Quality Standards for Benzene, Trichloroethylene,Tetrachloroethylene and Dichloromethane |