Haze due to build-up of particles in air: NEA, Latest Singapore News - The New Paper

Haze due to build-up of particles in air: NEA

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The slight haze yesterday was due to a build-up of particles in the air, said the National Environment Agency (NEA).

This was even as air quality entered the unhealthy range in parts of Singapore in the morning for the first time since late September.

It improved later in the afternoon and was in the moderate band, but re-entered the unhealthy range in the early evening.

The particles could be from various sources, from vehicle traffic emissions to smoke from fires in the region, said an air pollution expert.

NEA said in a post on Facebook in the late morning that the haziness earlier in the day was taking time to clear as winds have remained light since Tuesday evening.

"However, thunderstorms are expected in the afternoon, which should help to improve the situation," the agency added.


NEA said it was monitoring the situation closely and would provide updates when necessary.

At 7pm, the 24-hour Pollutant Standards Index (PSI) reading ranged from 88 to 105. A reading of 51 to 100 is in the moderate range, while a reading from 101 to 200 is in the unhealthy band.

The 24-hour PSI first entered the unhealthy range at 10am in the east with a reading of 101.

The one-hour PM2.5 concentration reading ranged between 34 and 71 micrograms per cubic m at 7pm.

Earlier at 10am, it was between 36 and 66 micrograms per cubic m.

A PM2.5 reading of 0 to 55 is in the normal band, while a reading of 56 to 150 falls in the elevated band.

PM2.5 readings measure the concentration of tiny particles less than 2.5 micrometres in diameter - or about one-thirtieth the diameter of a human hair - in the air. - THE STRAITS TIMES