Air Cabin Filter - Does it filter all air, including heater and A/C?

Greetings Leaf Users,

First post, just joined. I have no Leaf, but will buy a PEV within the next year and Leaf looks like the best bet by a wide margin.

And I joined the forum today to ask one specific question about the Leaf. I can't find the answer in the Manual, which I've downloaded, or in other Air Cabin Filter posts which I've read here.

Background to the issue: I understand from reading other posts that:
a) There is a cabin air filter.
b) It is user-changeable (with some effort).
c) After-market filters with activated carbon are available, so that chemicals/gases can be filtered in addition to particles.

I'm a person with a sometimes disabling high sensitivity to such gases (especially off-gases from rubbers, plastics, etc.) and so, not only filtering the exterior air pollution is of interest to me, but also the interior air pollution.

Specifically, in ICE cars I've driven (and the one I have), the heater adds noxious fumes, apparently from rubber hoses. Hot air over rubber hoses = bad air into the cabin.

So, finally, the question: does all the air entering the Leaf passenger compartment get filtered by the air cabin filter? Including that of the heater and A/C system?

Another way to put this: is the air cabin filter the last thing in the air chain? Because it will do no good, for my purposes of filtering the heater A/C air, if the air cabin filter is at the intake into the vehicle, before the climate system doctors it.

This issue has dogged me in ICE cars, and I'm hoping for an easy solution in the Leaf.

Anybody know?

(BTW, the manual says "The climate control system is equipped with an in-cabin microfilter which collects dirt, pollen, dust, etc." – but doesn't say if the filter is before or after the heater A/C -- hence this post.)

Thanking you in advance for any evidence or thoughts....

Looks like all air through the system is filtered. Which makes sense because you really don't want dust accumulating in the various cores and ducting as it would degrade performance over time and promote mold growth.

Nubo said:

Looks like all air through the system is filtered. Which makes sense because you really don't want dust accumulating in the various cores and ducting as it would degrade performance over time and promote mold growth.
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Thank you Nubo.

Do you have access to the full legend for this diagram? Or can I get the diagram somewhere?

I'd specifically like to know where the heater and A/C are situated.

My guess is they're #7 and #8.

If so, then the air is not filtered post-heater and A/C.

The fan motor is filtered, which is good. I've had experiences in other air filter systems where the fan motor was a significant source of pollution and the filter should be put after it.

But as for what happens after the heater in this Leaf air system, I suppose it will depend on how clear the heater itself is of volatile off-gassing parts, and how much of the travel ducting is metal and how much plastic and rubber. Which may vary in different year models, potentially -- and even, unfortunately, in the same year if a given rubber or plastic section is sourced from a different primary manufacturer who uses a different set of additives in their mix. That's why it's nice to have the filtering after all that crap -- which it doesn't seem to be.

Thanks again for posting this. I'm warned. :roll:

But it doesn't mean I have to give up. The air from outside is fully filtered, including the fan motor, and it might be possible to buy a separate heater and plug it into the power plug, and leave the heater off if the air from it bothers me.

AC is #4 (evaporator). #7 is inner condenser (heat-pump heat), and #8 is PTC heater core (resistance heat).

Afaik, it's general practice to place the filter at the beginning of the system, so that clean air flows over the coils and cores. post-filtering would require at least a 2nd additional filter. I've never had a car with 2 interior filters. Heck, I've only had a couple with any type of filter.

Keep in mind the cabin volume is small in comparison to the cubic feet per minute passing through the filter. So the interior air is being filtered repeatedly, regardless of the filter's location. An activated-carbon filter media might do the trick. Change it often at first -- high rate of off-gassing occurs when car is fairly new. I.e., the "new car smell".

ElectricAZ said:

... I'm a person with a sometimes disabling high sensitivity to such gases (especially off-gases from rubbers, plastics, etc.) and so, not only filtering the exterior air pollution is of interest to me, but also the interior air pollution.
...

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The 2011 new upholstery had awful volatile organic compound offgassing.
Was six to twelve months before it disipated.
Was so bad I left windows open with it parked in garage to help it off gas.

Have not heard much discussion of this in past couple years, so maybe the newer ones are better.

But all new cars have quite a lot of VOC off gasing.

With your sensitivity a two or three year old used vehicle may be a better choice.

TimLee said:

ElectricAZ said:

... I'm a person with a sometimes disabling high sensitivity to such gases (especially off-gases from rubbers, plastics, etc.) and so, not only filtering the exterior air pollution is of interest to me, but also the interior air pollution.
...

Click to expand...

The 2011 new upholstery had awful volatile organic compound offgassing.
Was six to twelve months before it disipated.
Was so bad I left windows open with it parked in garage to help it off gas.

Have not heard much discussion of this in past couple years, so maybe the newer ones are better.

But all new cars have quite a lot of VOC off gasing.

With your sensitivity a two or three year old used vehicle may be a better choice.

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Unfortunately my 2013 also had a terrible rubber smell for the whole first year, and it's still there, albeit reduced, after two. Both the Leaf and the Prius, ironically, have a serious indoor air pollution problem. You need to sit in a few new and used Leafs, in hot weather, to see how much it affects you.

LeftieBiker said:

TimLee said:

ElectricAZ said:

... I'm a person with a sometimes disabling high sensitivity to such gases (especially off-gases from rubbers, plastics, etc.) and so, not only filtering the exterior air pollution is of interest to me, but also the interior air pollution.
...

Click to expand...

The 2011 new upholstery had awful volatile organic compound offgassing.
Was six to twelve months before it disipated.
Was so bad I left windows open with it parked in garage to help it off gas.

Have not heard much discussion of this in past couple years, so maybe the newer ones are better.

But all new cars have quite a lot of VOC off gasing.

With your sensitivity a two or three year old used vehicle may be a better choice.

Click to expand...

Unfortunately my 2013 also had a terrible rubber smell for the whole first year, and it's still there, albeit reduced, after two. Both the Leaf and the Prius, ironically, have a serious indoor air pollution problem. You need to sit in a few new and used Leafs, in hot weather, to see how much it affects you.

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Thank you TimLee and LeftieBiker for this description of the interior off-gassing, and Nubo for comments about air flow and the layout of the heater.

These are the same things I've found in other cars and was hoping (without much hope, really) that they'd be different in the Leaf. I had seen that there was some progress in Japan about car interior VOCs, but apparently I'll have to assume the worst and try each car individually.

Yes, a two or three year-old car would be wise. Though a friend had a Prius and it was awful even several years old. Reminded me of jet fuel -- the smell in an airplane just before takeoff.

Amazing that we haven't all died of cancer yet.

I've imagined a possible solution would be to buy a couple of filters that use activated carbon, cut them to the shape of all the outflow vents, and fix them overtop somehow (or stuff them inside), airtight, to rig up my own full filtering system. It wouldn't look pretty but might do the job. Not sure, it might cause a backup of the air and interfere with the A/C. But I don't really need that, and it might work OK when the A/C isn't running.

Another tip, if one of the things you're sensitive to is mold/mildew...

Growth of mold and mildew in car AC systems can be a problem. It's fostered by moisture that condenses on the cold AC evaporator coils. There are 2 things you can do to minimize it.

1 - Periodically make sure the AC drain line is clear of debris to allow the condensate to run out of the car.

2 - when running AC, turn it off a few minutes before you reach your destination and leave the fan running on high. This will dry out the residual moisture and help prevent the growth of mildew. I have found this to be a big help and haven't had a funky AC since I started doing this.

Yes, a two or three year-old car would be wise. Though a friend had a Prius and it was awful even several years old. Reminded me of jet fuel -- the smell in an airplane just before takeoff.

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My housemate drives a 2013 Prius PHEV, and it smells like it was just repainted - inside. Her 2010 Prius II was pretty much the same.

Regardless of the number of filters put in the car's HVAC system, you're still stuck with the fact that the air will be tainted by contact with the materials of the cabin itself. It may be that your only recourse is activated-charcoal nostril insert filters.

Levenkay said:

Regardless of the number of filters put in the car's HVAC system, you're still stuck with the fact that the air will be tainted by contact with the materials of the cabin itself. It may be that your only recourse is activated-charcoal nostril insert filters.

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Thank you for this Levenkay. I didn't know about these -- a new product I think. I found a place that produces them ("Modern Alchemy") and I'll try some.

But I think Nubo's earlier point is worth considering too -- the air volume in the cabin is small, and so the question is how quickly the off-gassing is happening relative to the air being filtered. I had a rudimentary in-car filter by Faust, plugged into the cigarette lighter, and it helped a great deal. I could probably get one of those again, but it was a pain to have it taking up the passenger seat. It's isolating enough having chemical sensitivity without having to make the passengers sit in the back. So I'm going to try mocking up a paste-overtop-the-vent filter on my dying ICE car and see if that might work. If it does, I'll be embarrassed that I didn't think of it fifteen years ago. :roll:

And about whether to look for an older Leaf -- I did some reading online this afternoon and saw an interesting graph showing that approximately the first two months are the big ones for the most volatile of the new-car gasses, and even the less volatile, long-term ones, decrease substantially in the first three or four months, though not as large a proportion. And they mentioned that the early decrease happens fastest in hot weather -- which I could probably help along by keeping the car hot with the windows open (when I'm not in it) for the first few weeks. I remember that in Germany -- not about cars, but the same problem -- there's a law that new houses have to off-gas for a legally-mandated length of time before owners move in. Approaching it that way might help.

From my reading this afternoon it looks like there's a new awareness of the problem of in-cabin air generally, but, alas, car manufacturers will probably need to be nudged pretty hard before they'll take substantial action. But I think it has to happen; the descriptions I saw were of literally hundreds of chemicals; and yesterday, coincidentally, I saw a study reported on Medical Xpress about cancer causes that was making the point that our current regulatory system is flawed badly because we only measure single chemicals for their cancer-causing properties, when the current research is showing that combinations are synergistic that way. --So, putting those two things together, car cabins are a prime place for this to happen.

ElectricAZ said:

...But I think Nubo's earlier point is worth considering too -- the air volume in the cabin is small, and so the question is how quickly the off-gassing is happening relative to the air being filtered. . ..

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And of course, when condtions allow, Recirculate mode will filter more cabin air.

Nubo said:

And of course, when condtions allow, Recirculate mode will filter more cabin air.

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Right. And if worst comes to worst, I see that there's been an advance in the in-car air purifiers technology. Plugs into the 12-volt and sits under the seat or in the back:

http://www.modernalchemyair.com/products/allerair-mobileair-car-air-purifier/

It's not cheap but would probably do the job, especially the 'Vocarb' model, which they suggest for new cars.

My experience with air purifiers is that most of *them* out-gass a lot when new. I actually picked up a Germ Guardian unit to use in my car, but it stank too much to use.

LeftieBiker said:

My experience with air purifiers is that most of *them* out-gass a lot when new. I actually picked up a Germ Guardian unit to use in my car, but it stank too much to use.

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Fair enough. I've had the experience of a completely metal radiant heater unit — not for a car, for a house — that stank for almost a year, apparently because of a machine oil that was applied to some of the (non-moving) parts during manufacture.

But I've also had two purifiers that were made specifically for people with chemical allergies, and they helped a lot. So I think it depends on who is manufacturing, what they know, and what their target market is. The one I referenced is from a company (and web site) that appears to be centered on chemically sensitive people, so at least there's hope.

But first, I ordered a trial of 3 sets of nose filters for $11.99.

If that works, I'll be happy as a clam.