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Hazy conditions back in Singapore, but stay in moderate range
Publication Date : 18-09-2012
The haze has returned. At 3 p.m. yesterday, the three-hour Pollutant Standards Index (PSI) average hit 50, and stayed in the "moderate" range in the evening.
The higher pollution levels came after about a week's reprieve, after the PSI hit a one-year high of 79 on Sept. 7.
Air quality is considered unhealthy when the index crosses 100.
The hourly reading, given on the National Environment Agency (NEA) website between 7 a.m. and 7 p.m. daily, is the average of the previous three hours' air pollution levels.
At 4 p.m. yesterday, the 24-hour PM2.5 level - a measure of very fine particles in the air and another indication of air pollution - ranged from 28 micrograms per cubic m in the central region to 45 in the west.
A 40 to 65 range carries a health advisory by NEA for people to limit prolonged or heavy exertion.
These very fine particles are more able to penetrate the lungs and bloodstream than larger ones, rendering them more hazardous to health.
The annual haze is caused by farmers and logging companies in Indonesia who burn forests to clear land for cultivation.