XN000022-1994-05-13 — Page 29

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APRIL AIR QUALITY REPORT

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FRIDAY, MAY 13, 1994

THE ENVIRONMENTAL PROTECTION DEPARTMENT TODAY (FRIDAY) RELEASED AIR QUALITY INFORMATION FOR LAST MONTH.

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 CONTAINS MONITORING RESULTS FROM MONG кок, CENTRAL/WESTERN AND KWAI CHUNG. THESE 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 AREAS;

COMBINED COMMERCIAL AND RESIDENTIAL DISTRICTS; AND

DISTRICTS CLOSE TO INDUSTRIAL AREAS.

THE DEPARTMENT CURRENTLY MONITORS AIR QUALITY CONTINUOUSLY AT EIGHT STATIONS, INCLUDING THE THREE MENTIONED. SHORT-TERM MEASUREMENT CAMPAIGNS ARE ALSO UNDERTAKEN AS AND WHERE THE NEED ARISES.

THE REPORTED AIR

POLLUTANTS INCLUDE SULPHUR DIOXIDE (SO2), NITROGEN DIOXIDE (NO2), TOTAL SUSPENDED PARTICULATES (TSP) WHICH COMPRISE ALL SIZES OF DUST PARTICLES, AND RESPIRABLE SUSPENDED PARTICULATES (RSP) WHICH ARE THE RESPIRABLE FRACTION OF THE DUST.

ALL THESE POLLUTANTS CAN AFFECT

SUFFICIENT CONCENTRATION.

RESPIRATORY HEALTH IN

IN APRIL, THERE WERE TWO EXCEEDANCES OF THE SULPHUR DIOXIDE AIR QUALITY OBJECTIVE AT MONG KOK.

LEVELS OF NITROGEN DIOXIDE AND PARTICULATES WERE AGAIN HIGHER AT THE STREET-LEVEL MONG KOK SITE THAN AT THE ROOFTOP SITES AT KWAI CHUNG AND CENTRAL/WESTERN.

HIGHER NITROGEN DIOXIDE LEVELS AT ALL THREE STATIONS ON THE FIRST, SECOND AND 15TH OF THE MONTH WERE CAUSED BY CALM CONDITIONS WHICH PREVENTED VEHICLE EXHAUST FUMES FROM DISPERSING.

THERE WERE LOWER GASEOUS POLLUTANT CONCENTRATIONS TOWARDS THE END OF THE MONTH AT THE TIME WHEN SOUTHERLY WINDS BLEW FROM SOUTH CHINA SEA.

THE GASES AND PARTICLES DESCRIBED ORIGINATE FROM VARIOUS SOURCES. 502 IS MOSTLY PRODUCED WHEN FUELS THAT CONTAIN SULPHUR ARE BURNED. NO2 IS FORMED DURING COMBUSTION BY THE COMBINATION OF NITROGEN AND OXYGEN.

HOWEVER THE MAJORITY OF IT IS FORMED IN THE ATMOSPHERE BY THE OXIDATION OF NITRIC OXIDE (N.O.), ALSO A PRODUCT OF COMBUSTION.

/VEHICLE EXHAUSTS