Air purifier?

[WussRedXLi]

Spent another SGD30 to get the updated version of the PM2.5 monitor that I spent on last week.

Updated version changes :
1. sensitivity changed from 1 microgram/m3 to 0.1 microgram/m3, due to improved analog to digital convertor.
Doesn't mean that the accuracy is there, just that it's more sensitive to changes now.

Approx 0.2 PSI accuracy now for the lower PSI ranges that we usually experience. 0.1 PSI accuracy for the high range (moderate to dense haze).
This is coz the graph is non-linear

Can play with the calculator for conversion
http://www.airnow.gov/index.cfm/index.cfm?action=resources.conc_aqi_calc

2. Able to work from USB cable, so can plug to power bank for extended usage or your notebook etc. In addition to the 2 x AA that the previous gen was equipped to work with




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[Felixthecat]

I guess pet dander and stuff like mites faeces (usually they are allergens as well) do not really fly and stay in the air, those are more for smoke/haze. Even pollen stay in the air as they are lighter than dander.

So in your case, an air purifier does not help much. If you google about asthma and air purifiers, you'd get the same answer, if the allergen that is causing asthma is by dust mites' faeces, the purifier would not help much coz it'd settle very near to the bed, only to be spread around by say wind from the table fan or air conditioner.

But the activated charcoal in the purifier would help a bit with the smell.

Thanks for reply, like that then no point buying.

The Europace EPU 166C is not HEPA also leh....not even HEPA 10.

Wow! so expensive yet no HEPA? Frankly, I don't know what is what and I buy w/o checking specification. Last time bought one last pc of Sharp FZU31, if don't remember wrongly was $225, when everywhere out of stock. The sales guy say "last pc you want? if not must wait long long". I think I read somewhere here recently, FZU 31 is hepa 10, better one hepa 13, something like that.

 

[WussRedXLi]

HEPA10 can work as well....just wee bit less efficient in airflow specs comparatively. Still works for 0.1 microns etc...

I wouldnt be too concerned...coz taobao selling H12/ H13 replacement filters....tested with equipment by the seller.
Sgd20 shipped. If dont mind spending more on branded True hepa filters can get from Amazon, sgd30 shipped but need usd125 consolidated order to enjoy free shipping.

 

[WussRedXLi]

This one makes our PSI401 look like a walk in the park. 950 ug/m^3 is nearly 3 times of our record.



http://asiancorrespondent.com/95342...reported-in-beijing-culture-and-tourism-city/

At 950 micrograms per cubic meter, the PM2.5 level in Tongzhou, Beijing on January 13, 2013 is by far the highest figure ever recorded and reported. The number is as unthinkable to those who understand it as the news exposure of it to those who live in China.

PM2.5 measures airborne particulates of less than 2.5 micrometers in diameter. It is considered safe at 25 micrograms by the World Health Organization. Over the past few days, the PM2.5 readings in Beijing stayed dangerously high at 10 to 30 times more than the safe level, with Tongzhou’s reading topping the chart (ifeng News). According to Xinhua News, Tongzhou also had the highest concentration of nitrogen dioxide and sulfur dioxide among all of the districts in Beijing in 2011.

 

[mopiko_boy]

Guys, what mode do u use for the AX40? Do I use strong mode when just switched on, then sleep mode when I go to bed? But sleep mode seems very weak, or shld I use auto mode all the way instead?
Any advice?

 

[chuanz]

Use the highest setting which u can tolerate the noise.

 

[mosmos]

link: WHIRLPOOL AIR PURIFIER AP628W Air Purifiers - Courts Online Shopping

$279
Recommended Retail Price: $399

Applicable Floor Coverage Suitable for Room Capacity: 37.4 msq
Others Air Flow (metre cube/ min) : High: 3.4 / Mid: 2.2 / Low: 1.5
Digital Control Panel
WITH UV LIGHT FUNCTION
Pre-Washable Filter
HEPA Filter and Active Carbon Filter
Photo Catalyst Filter
LCD Color Display indicating air quality
4 Speeds: High/ Mi/ Low/ Auto
Dust Sensor and Nega-ion
5 Speeds Timer: 1/ 2/ 4/ 6/ 8 hrs
Air Flow (metre cube/ min) : High: 3.4 / Mid: 2.2 / Low: 1.5

 

[tmkedmw]

If we look at the specs of space coverage and air outflow for 2 examples below, it is obvious that suppliers adopt different specsmanship in selling their product.

How can a 205cu.m/hr product covers 37.4sqm space adequately when a 350cu.m/.hr product covers only 41sqm?


WHIRLPOOL AIR PURIFIER AP628W, coverage 37.4sqm, 3.4cubic metre/min or 204 cu. m/hr

Samsung AX40 41 sqm, 350 cu. m/hr

In my opinion, using ACH (Air change /hr) is the right spec to look for.
Aim to have a nominal ACH of 6, with 4 as a minimum.

 

[tmkedmw]

This one makes our PSI401 look like a walk in the park. 950 ug/m^3 is nearly 3 times of our record.

Appreciate your contributions in this thread.
PSI401 in Singapore was using the old method then (PM10?).
950ug/cu.m in China is however based on PM2.5.

Can't figure out how to conclude that 950ug/cu.m is nearly 3 times our record (using conversion calculations in w.w.w.airnow.gov. I still can't post url links.

 

[WussRedXLi]

Appreciate your contributions in this thread.
PSI401 in Singapore was using the old method then (PM10?).
950ug/cu.m in China is however based on PM2.5.

Can't figure out how to conclude that 950ug/cu.m is nearly 3 times our record (using conversion calculations in w.w.w.airnow.gov. I still can't post url links.

Hi there,

Thanks for your post, good to see that you appreciate the technical fine-print.

Anyway, i also bo liao lah....just digging up info from other countries. Just for general knowledge. But i was chatting with some taobao sellers, and the air there is seriously v bad, that's why google more info.


Our PSI 401 peaked on 21st June Friday, at 11-12 noon period. You are correct to say that it's PM10 for 3-hr period. You know there are some differences between AQI (Beijing, US Embassy etc), API (Malaysia) and even our own local 3-hr moving avg (PM10 right?) + 24-hr average (PM2.5) are all very different.

But to keep it simple, check out the historical records. We hit 298 ug/m3 tops at 10AM for North side.
National Environment Agency

I am not sure how is 950ug/m3 in Beijing measured. Is it peak 1hr or 5 mins (if you read taobao, i think they do that sometimes) or is it like our 24-hr?

But for what it's worth, 298 vs 950 ug/m3, it's a very wide gap.
That's nearly 3X.


More sauce :
Haze update: PSI 401 at noon; many pharmacies still out of masks

The three-hour Pollutant Standards Index (PSI) climbed to 401 at noon on Friday, firmly into the hazardous range. This was a slight increase from 400 at 11am. Anything above 300 is hazardous. The 24-hour average PSI was 181-232, up from 180-227 an hour before. The 24-hour average concentration of PM2.5, which is very fine particulate matter, was 232-292. -

 

[WussRedXLi]

Wiki page . Got detailed logs of the PSI and PM2.5 concetration readings.
2013 Southeast Asian haze - Wikipedia, the free encyclopedia

In order not to confuse others, this is the PSI 401. Not many can undersstand micrograms per metre cube.

 

[WussRedXLi]

If we look at the specs of space coverage and air outflow for 2 examples below, it is obvious that suppliers adopt different specsmanship in selling their product.

How can a 205cu.m/hr product covers 37.4sqm space adequately when a 350cu.m/.hr product covers only 41sqm?


WHIRLPOOL AIR PURIFIER AP628W, coverage 37.4sqm, 3.4cubic metre/min or 204 cu. m/hr

Samsung AX40 41 sqm, 350 cu. m/hr

In my opinion, using ACH (Air change /hr) is the right spec to look for.
Aim to have a nominal ACH of 6, with 4 as a minimum.

For those who are more techie minded, we just look at the m3/hr spec. That would be directly comparable. With just a bit of conversion, you can compare with the CFM spec.

This figure is also very very close to the CADR figures that you see in USA sites. (they are imperial, so that's CFM)

 

[tmkedmw]

...
Our PSI 401 peaked on 21st June Friday, at 11-12 noon period. You are correct to say that it's PM10 for 3-hr period.
...
The three-hour Pollutant Standards Index (PSI) climbed to 401 at noon on Friday, firmly into the hazardous range. This was a slight increase from 400 at 11am. Anything above 300 is hazardous. The 24-hour average PSI was 181-232, up from 180-227 an hour before. The 24-hour average concentration of PM2.5, which is very fine particulate matter, was 232-292. -

Oh, i see, did not realise that PM2.5 was available from NEA then since what was on TV and media is mainly the PSI number.

As for the 3hr moving average of PSI401, I recall that some were trying to say that the instantaneous PSI (the hr when PSI401 was reported) was much greater than 401 since the data stream was going up and up in the last 3 hours (moving average mah..)

As usual, thanks for your detail reply.

 

[tmkedmw]

For those who are more techie minded, we just look at the m3/hr spec. That would be directly comparable. With just a bit of conversion, you can compare with the CFM spec.

This figure is also very very close to the CADR figures that you see in USA sites. (they are imperial, so that's CFM)

Yes m3/hr spec is directly comparable across models.
There is always a question of what size purifier shld one buy.
Bigger is better but price and noise is also a consideration.

Therefore m3/hr must be seen in relation to the volume of the room that one intends to use the purifier.
Hence, this newbie is advocating using ACH to determine what size purifier should one buy.

ACH is simply m3/hr divided by volume of air in room in m3.
Volume of air in room = area x height (all in m)

Qualitatively it means your room has your dirty air changed ACH times every hour.

An example of a very high requirement for ACH is a hospital burns care centre. SGH one is spec at 20 ACH.

 

[chuanz]

But wouldn't ACH introduce another variable? Obviously your room and my room not same size (unless everything including furnishing exactly the same). Most ppl dunno the room size, must less the room volume!

 

[Akai Ryu]

AX40 cannot tune auto mode sensitivity?

 

[WussRedXLi]

Qualitatively it means your room has your dirty air changed ACH times every hour.

An example of a very high requirement for ACH is a hospital burns care centre. SGH one is spec at 20 ACH.

My regular bedrooms are those new-age pathetically small rooms. I think with a built-in cabinet, books cabinet and speakers and what nots, my computer/PC/music room is just 12 sqm x 2.8m = 33.6 m3.
My MBR with king sized bed, TV console, cabinets, false ceiling is probably 65 m^3 tops.

I once operated them altogether for a few days, just for fun. A Sharp KC-840 with H13, Novita NAP501 and Samsung AX40. That's 800m3/hr.

Air Changes per Hour would be 23.8X and 12.3X.

4pcs of Samsung AX40 gives you 1400 m3/hr for a tad over 1k, delivered.
If anyone is after that 20X ACH figure.

 

[WussRedXLi]

But wouldn't ACH introduce another variable? Obviously your room and my room not same size (unless everything including furnishing exactly the same). Most ppl dunno the room size, must less the room volume!

Agaration lah... Of course need to use some 10-mins elbow grease and measure a bit.

m3/hr airflow is cheap with Samsung AX40.

 

[Asure7]

most hdb should be 2.4m floor to ceiling.
dbss 2.6m ... EC maybe 2.8m.

you'll have to estimate area anyway. . just multiply by 3 if want to be kiasu lor. some over-provisioning is always good

easiest way is to look at your floor plan.

 

[starbuckss]

Brand New Novita Air Sterilizer NAS 300 for sale.
Retail $119 now selling $80.
Grift from friend.
Pm me if interested...