Zit Seng's Blog

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Hourly-Adjusted PSI Reading

20130620_085033I think we can say that we’re sort of experiencing a national emergency now. The PSI readings have reached hazardous levels since last night. More interestingly, you should have realised that you often feel that the haze situation is far worse than what NEA is reporting through their PSI readings. Why is it so?

Well, the PSI readings from NEA reflect the situation in the preceding three hours. That’s why they call it the 3-hour PSI level. When the haze condition worsens rapidly, the PSI readings will seem to “lag” behind, because it is reflecting a the situation for a time period farther back than “right now”.

It’s probably fair to say that most of us are really more interested in what’s happening “now”.

Here’s the daily graph of hourly-adjusted PSI figures. It’s possible that these readings don’t make sense, so just take it with a generous serving of salt.

Red is the hourly-adjusted figure, and green is the three-hour PSI reading from NEA.

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Note: The above data is currently being updated automatically during the current haze situation.

The previous day graph is below.

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16 thoughts on “Hourly-Adjusted PSI Reading

  1. even more interesting is that NEA’s PSI only includes PM10 levels but not PM2.5 levels (which is cause of drop in visible AND much more dangerous to our health compared to PM10). US EPA PSI already updated to include PM2.5 levels in 1999 and renamed to AQI, while NEA is still dragging its feet…

    1. I’m convinced NEA’s servers are made up of calculators…
      Since their CDN can’t handle the load to serve static pages, their backend servers probably can’t handle the calculations of more data beyond the existing 3-hrs average for PM10.

    1. I got the same too. Anyway, that 3-hr average couldn’t have dropped more than 100pts in just an hour. For the adjusted to stay above 0 at that hr, the average should be near 280 instead.

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