Page auto-refresh every 5 minutes Monitoring stopped. Will resume if haze comes back.Resumed on 12 Jul 2013


Scroll down for additional graphs, and explanations.

26 Jun 2013: Comparing PSI, AQI, pm10, pm2.5
28 Jun 2013:Readings from 10am, 27 Jun 2013 (Thu) to 11am, 28 Jun 2013 (Fri) unreliable due to equipment fault
30 Jun 2013:Percentage of PM2.5 over PM10
3 Jul 2013:Added 1-month graphs at bottom of this page
7 Jul 2013:Graphs will stop updating from 7 Jul 2013. Will resume if haze comes back
12 Jul 2013:Graphs updated from 13 Jul 2013 5am

Realtime graph of particle count (1 micron and above) in Punggol 21
Graph is updated every minute. Refresh the page to see latest graph.

Please note this graph is different from pm2.5 or pm10 readings, although there is likely to be positive correlation.

my graphs = estimated total number of particles, size 1 micron and above (number of particles per cubic foot)
PM10 = total weight of particles, size < 10 micron (microgram per cubic metre)
PM2.5 = total weight of particles size < 2.5 microns (microgram per cubic metre)

My particle counter readings are not equivalent to PM10 or PM2.5,
but can be a useful proxy, with good correlation. I have created a graph
with 3-hr PSI data obtained from NEA twitter feed for comparison.

Howto (diy) instructions are at Instructions for "building" realtime graphing for particle counter


The green area shows the particle count per minute. Red line shows 3-hr moving average.

M is Million. K is thousand. i.e. 1.1 M means 1100000 particles bigger than 1 micron, per cubic foot.

Very Rough Guide (i.e. not backed by scientific evidence, provided as-is)
--------------------------------
1M and above = Hazardous
0.7M to 1M = Very Unhealthy
0.2M to 0.7M = Unhealthy
0.1M to 0.2M = Moderate
below 0.1M = Acceptable

Usual count before current haze conditions was 15K to 80K, with occasional spikes to 120K.

The moving average is there only to show correlation with NEA 3-hr PSI, and show that my graphs are valid approximate representations of current air quality.
3-hr PSI graph, with data extracted from NEA twitter feed, is just below this bunch of text.

The other purpose of plotting the 3-hr moving average, is to show why the 3-hr moving average is misleading and ultimately useless to the general public when conditions change rapidly.
The 3-hr PSI may be reporting "Moderate" air quality, for up to 3 hours, while actual conditions may have reached "very unhealthy" levels.

3-hr moving average is pretty much useless otherwise. If you have to choose between your nose and eyes OR NEA 3-hr PSI, go with your nose and eyes.








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