TUESDAY, SEPTEMBER 14, 1993
16
AIR QUALITY REPORT FOR AUGUST
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THE ENVIRONMENTAL PROTECTION DEPARTMENT TODAY (TUESDAY) RELEASED AIR QUALITY INFORMATION FOR AUGUST.
A SPOKESMAN FOR THE DEPARTMENT SAID THE PURPOSE OF THE ANNOUNCEMENT WAS TO KEEP THE PUBLIC INFORMED OF THE AIR QUALITY LEVELS IN THE TERRITORY AND TO EXPLAIN THE MEASUREMENTS.
THE ANNOUNCEMENT NORMALLY CONTAINS MONITORING RESULTS OBTAINED AT ITS MONG KOK, CENTRAL/WESTERN AND KWAI CHUNG MONITORING STATIONS,
THE LOCATIONS ARE TYPICAL OF THREE OF THE IMPORTANT LAND USE TYPES FOUND IN THE TERRITORY:
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LOCATIONS CLOSE TO ROAD TRAFFIC IN BUILT-UP URBAN DISTRICTS,
COMBINED COMMERCIAL AND RESIDENTIAL DISTRICTS, AND
* DISTRICTS CLOSE TO INDUSTRIAL AREAS.
THE REPORTED AIR POLLUTANTS INCLUDE SULPHUR DIOXIDE (802), NITROGEN DIOXIDE (NO2), RESPIRABLE SUSPENDED PARTICULATES (RSP) AND TOTAL SUSPENDED PARTICULATES (TSP).
THE GASEOUS POLLUTANTS ARE MONITORED CONTINUOUSLY WHILE PARTICLE SAMPLES ARE COLLECTED FOR 24 HOURS, NORMALLY ONCE EVERY SIX DAYS.
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FOR A PERIOD OF THREE DAYS STARTING FROM AUGUST 24 HONG KONG EXPERIENCED SIGNIFICANT DEGRADATION OF VISIBILITY AND INCREASED AIR POLLUTION LEVELS.
THE VISIBILITY REDUCTION WAS WIDESPREAD, WITH REPORTS FROM AIRCRAFT AND OTHER OBSERVATIONS INDICATING THAT HAZY CONDITIONS PREVAILED OVER COASTAL AREAS MORE THAN 100 KILOMETRES FROM HONG KONG AND UP TO HEIGHTS OF TWO KILOMETRES ABOVE THE SEA.
IN THIS EXTENSIVE AREA OF STAGNATION, CALM WIND CONDITIONS COUPLED WITH A VERY STABLE ATMOSPHERE INHIBITED DISPERSION OF AIR POLLUTANTS AND CAUSED AN AIR POLLUTION EPISODE IN HONG KONG.
ELEMENTAL ANALYSIS OF SAMPLES COLLECTED SHOWED A SUBSTANTIAL AMOUNT OF CARBON IN THE PARTICULATES, A RESULT OF DIRECT EMISSION FROM URBAN COMBUSTION SOURCES SUCH AS DIESEL ENGINES.
AN INCREASE IN SULPHATE CONTENT WAS ALSO NOTICED, MAINLY BECAUSE OF THE TRANSFORMATION OF SULPHUR DIOXIDE EMITTED BY FUEL BURNING SOURCES INTO SULPHATE UNDER THE INFLUENCE OF VERY STABLE ATMOSPHERIC CONDITIONS.
LOCAL WINDS GRADUALLY PICKED UP ON AUGUST 27 AND BETTER DISPERSION CONDITIONS SUBSEQUENTLY BROUGHT DOWN POLLUTANT LEVELS.
/AT THE