The following report was printed in The Indonesian Observer,
a leading daily newspaper, on 6 December 1998 (Reuters)
SINGAPORE – Singapore’s skyline was murky again on Tuesday after winds proved too light to blow away lingering smoke haze from forest fire “hot spots” in Indonesia.
The air quality, which hit its worst level in about six months over the weekend, stayed in the moderate range on Tuesday. “We are in this light and variable wind situation,” said Wong Teo Suan, deputy director of Singapore’s Meteorological Service. He said lights southwest winds on Friday sent smoke haze from the Riau Province in Central Sumatra over the city-state. “Over the weekend … the winds actually did change back to the northwest as we expected, but it was unfortunately, a bit too light to clear away the haze so fast,” he said.
Low level winds swung back to the southwest on Tuesday. “It is a time of year when winds are very light and variable because we have not had the full blast of the monsoon over the region,” he added.
The smog pushed the city state’s Pollutant Standard Index (PSI) measure of air quality up to 59 in the late morning, a spokesman from the Environment Ministry told Reuters. The air quality improved slightly over the day, registering 57 PSI in the late afternoon. The reading of 57 puts air quality in the moderate range, and was slightly below Friday’s peak of 69, the worst level since May and one of the highest readings this year.
A PSI between zero and 50 is considered good. A 51-100 range is “moderate”, 101-200 “unhealthy”, 201-300 “very unhealthy”, 301-400 “hazardous”, and 401-500 “very hazardous”.
Wong said the situation this year was very different from the previous year, when skies were blanketed for several months. the fires this time were not large but “localised” ones.
The few isolated hot spots in Central Sumatra were quite near to Singapore and prevailing winds had carried some smoke haze over. “I think the situation will start to improve over the next few days, with some change in winds to the northwest,” he said.
He said the high pressure over China was forecast to push down south over Hong Kong, strengthening the northeast winds.
“When the northeast winds come back to our region I think there could be a chance for some increased rainfall in this area, and hopefully, over Sumatra”, Wong said. He and Singapore could expect to see more rain in the second half of December into January and February. Singapore and many other Southeast Asian nations were blanketed by a choking could of fire-driven smoke haze in the latter part of 1997.