EPD's statement on heavy metals in air
In response to a study conducted by a group on the heavy metal concentration of flying ash generated by power companies and the claim of insufficient monitoring and control by Government on October 3, 2005, a spokesman for the Environmental Protection Department (EPD) said that the emission of heavy metals is well under regulation and their levels in the ambient air are also regularly monitored.
The spokesman said that all air polluting sources and processes emitting heavy metals, such as heavy metal recovery, lead process, incinerators and incineration of chemical waste, were regarded as Specified Process under the Air Pollution Control Ordinance and subject to the control of a licensing system.
"Under the Air Pollution Control Ordinance, such processes are required to adopt the best practicable means to prevent the emission of heavy metals and other air pollutants," he added.
"Coal-fired electricity generating process is also subject to the Specified Process licensing under the Air Pollution Control Ordinance. Power companies are required to use electrostatic precipitator with efficiency over 99 per cent with a view to reducing the emission of pulverized fuel ash and heavy metals contained by the ash," the spokesman said.
The spokesman reiterated that EPD had all along been regularly monitoring the levels of various metals in the ambient air.
"The monitoring data has indicated that the emission of various heavy metals is effectively maintained at low levels. Among them, the average concentration of mercury and arsenic are 0.23 ng/m3 and 7.11 ng/m3 respectively," he said.
"They are well below the standards set by California in the US. The levels of other metals are also much lower than the California standards," he added.
The monitoring data of various heavy metals in the ambient are available at EPD's website at http://www.epd-asg.gov.hk/english/report/files/ea04e.pdf.
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