XN000022-1993-11-12 — Page 17

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FRIDAY, NOVEMBER 12, 1993

DESPITE THE DAYS OF HIGHER CONCENTRATIONS, THE MONTHLY AVERAGE TSP LEVEL OF 147 UG/CUBIC METER AT MONG KOK WAS CONSIDERABLY LOWER THAN IN OCTOBER LAST YEAR WHEN THE AVERAGE WAS 212 UG/CUBIC METER.

SINCE THE OTHER TWO SITES EXPERIENCED ONLY SLIGHTLY LOWER MONTHLY AVERAGES THIS YEAR THAN LAST YEAR, THE SIGNIFICANT DECREASE AT MONG KOK IS ATTRIBUTED TO A DECREASE IN LOCAL EMISSIONS.

LEVELS OF NO2 AT MONG KOK WERE HIGH THROUGHOUT THE MONTH BUT DID NOT EXCEED THE 150 UG/CUBIC METER 24-HOUR LIMIT.

THE FOUR POLLUTANTS DISCUSSED MOSTLY ORIGINATES FROM THE COMBUSTION FUELS.

HAVE DIFFERENT ORIGINS. S02 OF SULPHUR CONTAINING FOSSIL

NO2 IS FORMED EITHER DIRECTLY DURING COMBUSTION OR, BY THE ATMOSPHERIC OXIDATION OF NITRIC OXIDE (NO) WHICH IS ALSO PRODUCED DURING COMBUSTION.

VEHICLE EXHAUST IS A MAJOR SOURCE OF NO AND NO2.

IT IS ALSO A MAJOR SOURCE OF AIRBORNE PARTICLES; OTHER SOURCES INCLUDE INDUSTRY, FURNACES AND BOILERS, CONSTRUCTION ACTIVITIES, THE SEA AND SOIL DUST.

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

ENQUIRIES CAN BE DIRECTED то PRINCIPAL ENVIRONMENTAL PROTECTION OFFICER, MR RAYMOND LEUNG ON TELEPHONE 594 6401.

HONG KONG