Hi WRX, I've bought the 汉王m1 as per recommendation in your previous thread, can I check with you on why the readings differ that much with nea's 1hr pm2.5 readings? Mine was showing 70-90 ug/m3 pm2.5 now in orchard rd. Can help to shed some light on this? Thanks.
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Thanks confirming my readings. Mine is also same region.
NEA 1hr is past 1hr period sampling averaged. However, since like what....9 or 10AM already like that, elevated. I don't see no 20-30 ug/m3. Note - this is not even US EPA Unhealthy for Sensitive Grp, in which the breakpoint is 36ug/m3.
Check NEA's PM10. There are no spikes or elevated readings since 2 days ago, ie this is not PM10 coarse particles. Its mainly PM2.5 fine stuff. My floor also does not have ashy feeling etc, unlike in 2013 (mainly PM10 main pollutant).
NOt sure what is happening, but yours and mine same readings.
I think NEA is using that beta attenuation tech, something like that. This tech .
Beta attenuation monitoring - Wikipedia, the free encyclopedia
That is not to say that ours is 100% correct. After all, our devices are like K-mart toys compared to professional samplers. However, there are devices like those from Met-One that use the same laser technology and cost a few thousand USD. You can see the Met One used in the demo booths of Novita NAP611i at shopping malls. Same tech.
Since you are serious enough to have bought an air quality monitor (somemore is laser particle sensor type, not cheap IR LED stuff used in air purifiers), I guess your health depends somewhat on it. Errr on the side of caution esp for those serious asthmatics, or worse...asthmatic kids (double whammy). I understand that each individual and family circumstances/usage/needs are different.
The 3-hr PSI is calculated from the N S E W and C PM2.5 (main pollutant) readings, all added and averaged out. 3-hr moving average. So you can imagine.
Put it this way, the worstest tiong made $2 digital thermometer will tell you that the water is boiling hot.
