FRIDAY, AUGUST 13, 1993
DUST LEVELS WERE, AS CENTRAL/WESTERN AND KWAI CHUNG.
THE MONTHLY AVERAGE
TIMES HIGHER THAN LAST
USUAL, HIGHER AT MONG KOK THAN AT
SO2 CONCENTRATIONS AT KWAI CHUNG WAS 2.5 YEAR. BY CONTRAST, AT MONG KOK AND CENTRAL/WESTERN LEVELS WERE LOWER THAN LAST YEAR.
THIS YEAR, PEAKS OF 24-HOUR SULPHUR DIOXIDE CONCENTRATIONS WERE OBSERVED AT KWAI CHUNG ON THE 27TH AND 30TH BUT NOT AT THE OTHER TWO SITES. HOWEVER, THE PEAKS WERE WELL, BELOW THE 24-HOUR LIMIT OF 350 UG PER CUBIC METER.
COMPARED TO LAST YEAR, NITROGEN DIOXIDE LEVELS WERE 2.5 TIMES HIGHER AT KWAI CHUNG, SLIGHTLY HIGHER AT MONG KOK AND SLIGHTLY LOWER AT CENTRAL/WESTERN.
IN ABSOLUTE TERMS, THOUGH, NITROGEN DIOXIDE LEVELS WERE STILL HIGHEST AT THE STREET LEVEL SITE OF MONG KOK.
THE DEPARTMENT 1S INVESTIGATING THE TREND OF THESE HIGHER POLLUTION LEVELS IN KWAI CHUNG.
THE FOUR POLLUTANTS DISCUSSED HAVE DIFFERENT ORIGINS. SO2 MOSTLY ORIGINATES FROM THE COMBUSTION OF SULPHUR CONTAINING FOSSIL FUELS.
NO2 IS FORMED EITHER DIRECTLY DURING COMBUSTION OR, BF THE ATMOSPHERIC OXIDATION OF NITRIC OXIDE (NO) WHICH IS ALSO PRODUCED DURING COMBUSTION.
VEHICLE EXHAUST IS A MAJOR SOURCE OF NO AND NO2.
CONSTRUCTION
IT IS ALSO A MAJOR SOURCE OF AIRBORNE PARTICLES; OTHER SOURCES INCLUDE INDUSTRY, FURNACES AND BOILERS, ACTIVITIES, THE SEA AND SOIL DUST.
THE DEPARTMENT IS CURRENTLY MONITORING AIR QUALITY CONTINUOUSLY AT 11 STATIONS, INCLUDING THE THREE MENTIONED ABOVE. SHORT-TERM MEASUREMENT CAMPAIGNS ARE ALSO UNDERTAKEN AS AND WHERE THE NEED ARISES.
NOTE TO EDITORS:
FURTHER
ENVIRONMENTAL
ENQUIRIES
CAN BE
DIRECTED
ΤΟ
PRINCIPAL
PROTECTION OFFICER, MR RAYMOND LEUNG, ON TEL 594 6401.
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