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NEA to provide hourly PSI readings until haze ends

Updates will also be the average of previous three hours

Published on Sep 8, 2012 6:00 AM

With the haze worsening yesterday, the authorities have started providing hourly updates to keep the public better informed.

Previously, readings of the Pollutant Standards Index (PSI) were taken only at 8am, noon and 4pm daily, and they reflected 24-hour averages.

Since yesterday, readings have been taken hourly, and they reflect the average of the PSI readings for the previous three hours.

Readings from 7am to 7pm will be posted on the National Environment Agency's (NEA) website.

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Background story

New PSI readings

PSI readings taken at 8am, noon and 4pm are 24-hour readings averaged over the past one day. But the new hourly readings introduced today are averaged from the readings of the preceding three hours. While the 24-hour reading is more accurate, the hourly reading is more relevant for people making decisions about outdoor activities, said a spokesman for the National Environment Agency.