HEPA filters for car cabin useless on our health

[V200]

Just got my hands on this particle counter for some data collection. After I was done, decided to do a little test on my own.

 

Heared of this HEPA filter before? Well, I tried it with the aircon full blast. See what's the result.

Edited September 10, 2008 by V200

[V200]

Next I removed the "HEPA" filters

 

 

[Munkong]

What do the readings mean?

[V200]

Then I measured again.

[V200]

I did not believe the results, so I tested again.

[V200]

The readings means how much particles there are blowing from the aircon duct per minute. For this case, it was about 1 million 0.3microns particle per cubic feet per minute.

(Need to multiply by 10). With or without the filter the readings were simliar.

This means that either the air con coil and small ductwork from fan to the air con vents are constantly releasing particles, or the HEPA filters don't work. I personally think the HEPA don't work.It just prevents big particles from getting stuck in the air con coils.

Edited September 10, 2008 by V200

[Ender]

Did you let the air con run for a few hours or a day before you take the 2nd round of reading? There're residual particles in the air duct after the air filter to your counter, that will take times to clear.

[V200]

No leh. But turning the fan to full blast should clear the residue particles right? At least the readings should show significant difference rather than same for with and without particle filters.

[Ender]

If you still have the counter on loan, maybe can ty taking the reading again after some usage. Don't know if it'll make a diff.

[Tkseah]

So your test reading is one with HEPA filter and one without any filter??

[V200]

Yup. My test was done with the HEPA. I removed the filter then took the second reading.

[V200]

The counter won't be with me for long. Doubt I could keep test it again. Anyway, was running the aircon full for 5 mins because I kept taking the readings. Should be accurate.

[Southpark2000]

The readings means how much particles there are blowing from the aircon duct per minute. For this case, it was about 1 million 0.3microns particle per cubic feet per minute.

(Need to multiply by 10). With or without the filter the readings were simliar.

This means that either the air con coil and small ductwork from fan to the air con vents are constantly releasing particles, or the HEPA filters don't work. I personally think the HEPA don't work.It just prevents big particles from getting stuck in the air con coils.

 

I am no salesman of HEPA filter.....but a bit unfair leh - yr testing.....and so is yr title of post - misleading leh.....

 

http://www.cairefresh.com/pdt-automotive.htm

 

[/indent]

CaireFresh

Edited September 10, 2008 by Southpark2000

[V200]

Er...did not say brand name of filter hor....

 

As for the title of the post, I wanted to change but cannot leh.

 

Anyhow, would you believe it, HEPA filters in market has an efficiency of 99.99% depending on grade. This so called HEPA filter has 99% efficiency.

However, from the readings, even if you were to take my 0.5 microns readings as 500 difference, isn't that only 10% reduction and virtually no impact on 0.3 microns at all.

 

Can let me know your thoughts, maybe do another test (if can find the time).

[Biglittlebean]

Just my opinion, the experiment may not be an accurate one since you have been using the HEPA filter in your aircon in the first place. The air particles may have been filtered out prior to that and hence it already has less particles. That's why when you take out the filter, the readings does not show significant improvement. Perhaps, to make the test fairer, maybe you can take out the filter and use your car for one week first and then do a reading, followed by another week with the filter.

 

Cheers

[Zippaboy]

how about testing with the recirculation mode off?

[Genie47]

That is why I buy the OE ones from the car manufacturer. They are cheaper by a wide margin compared to the HEPA ones. 22-24 bucks for the OE compared to a whopping almost 40 for the HEPA. Still need to change every 10k for me.

[Genie47]

That would be a good variable to investigate.