Residential VOC standards - Can PCO (MoleKule, RGF, lots of others) help?

[randyf]

The United States Green Building Council (USGBC) has established a standard for indoor residential VOC levels. The spec is available here:https://www.usgbc.org/credits/new-co...retail-new-c-8

Total VOC Levels (TVOC) for residences should be below 500 ng/liter.That means if you collect a liter of indoor air and separate and weigh all the VOCs in the sample the total weight should be under 500 billionths of a gram. There are a number of labs that offer test kits to the public. I've used these two:

https://homeaircheck.com/products/ Least Expensive.

https://www.fikeanalytical.com/ High Quality, recommended

Both testing labs use a version of Gas Chromatography/Mass Spectrometry called TO-17. All significant VOCs are totaled to determine the TVOC levels. Typically about 50 -400 different VOCs make up the total level. Home Air Check (prism labs) has tabulated a median of about 1200ng/liter for thousands of homes tested. This is about 2.2 times the maximum standard of 500ng/liters.

I find it curious that the major manufacturers of Photocatalytic Oxidizers (PCO) devices (MoleKule, RGF) never report VOC tests in homes. I think I know why. This technology works where different VOCs are limited and are at unusually high concentrations in special chambers. Not the environment we find in our homes. This characteristic has been noted in the scientific literature.

Here’s a quote from a recent overview of PCO technology in a scientific journal:https://www.mdpi.com/1420-3049/21/1/56/htm - Highly recommended article!

“Currently most studies demonstrate their VOCs removal efficiency in a high concentration level (e.g., ppmv). More on-site demonstrations should be conducted in order to prove the efficiency in removal of indoor VOCs in realistic environments (e.g., residential and work spaces).”

Until this is demonstrated I have doubts about the effectiveness of these devices for VOC reduction in homes. Why else would the companies that do test always resort to very small test chambers with walls of stainless steel using just a few VOC at super high concentration. If these devices really worked the way the consumer want’s, in homes, these companies would test - in homes. Why spend tens of thousands of dollars for contrived setups when simple, cheap testing in real living spaces would resolve all doubt.

[blivengo]

hi
I know this is an old thread but wanted to ask you some quesitons since it seems you know a lot about the subject. I recently got one of the cheap detectors on amazon and am seeing high vocs. Interestingly they increase dramatically as you go up floors. The basement averages .5 mg/m^3. First floor is 3 mg/m^3. Second floor is 6 mg/m^3. The formaldehyde, pm2.5, and pm10 are low. I plan on getting test from one of the companys you have recommended to verify. Do you have any insight into why VOCs would be higher on upper floors? Also is it possible even though total vocs are high, that the harmful ones are not necessarily high? The outdoor air measures around .1 which is not zero but seems pretty low. I am within a mile or 2 of a natural gas compressor station, which puts out a lot of vocs.

[teddy bear]

We do not yet know all of the VOCs that effect us yet. Their concentration varies with the amount of air passing through the home and the activity of the occupants.

We need high oxygen levels for optimum health. Outside air is 21.5% oxygen with inside air minimum of +19.5% oxygen suggested. Spot checking for optimum levels of anything is questionable.

Why not assure fresh air change when occupied by monitoring CO2 levels in the home and activating a small of amount of fresh filtered air ventilation when CO2 levels are significantly above outdoor levels. A fresh air change in 3-5 hours is suggested by most experts. 80 cfm per 2,000 sq.ft. home would do most. One person breathing in a home with less than 50 cfm of fresh air would measure +650 ppm CO2 with 450 ppm outside CO2. You could pick any air change rate you want. When the wind blows winter average, +- 7 mph, most homes do not need fresh air. One person would not release enough CO2 to trigger fresh air ventilation. Calm summer nights with windows closed, the fresh air change rate slows to a fresh air change in +12 hours in most well built homes. One person would trigger the fresh air ventilation setting of +650 ppm CO2.

CO2 controllers are available for <$200 from many. Fresh filtered air change when occupied and with inadequate natural is not expensive. In green grass climates, add humidification and dehumidification maintaining +40% and <55% RH for comfort and health provides a near perfect indoor condition. Most climates require <$200 conditioning per year for common houses.

Occupants will grow older and be more healthy and comfortable!
Hard to get this simple message across.

Regards Teddy Bear

[RoBoTeq]

I can't agree more. Indoor air quality has become worse due to tightening up of homes and introducing a lot more VOCs in the everyday products we use. Ozone reduces VOC's extremely well but must be cautiously administered. I use a very low-level ozone generator in my bedroom where I keep the cat's litter box. I never smell anything from that litter box. Once in a while I will remove the cat from the house and run a commercial ozone generator for 30 minutes while my son and I are out for a few hours. It is amazing the difference in the odor reduction.

We do not yet know all of the VOCs that affect us yet. Their concentration varies with the amount of air passing through the home and the activity of the occupants.

We need high oxygen levels for optimum health. Outside air is 21.5% oxygen with inside air minimum of +19.5% oxygen suggested. Spot checking for optimum levels of anything is questionable.

Why not assure fresh air change when occupied by monitoring CO2 levels in the home and activating a small of amount of fresh filtered air ventilation when CO2 levels are significantly above outdoor levels. A fresh air change in 3-5 hours is suggested by most experts. 80 cfm per 2,000 sq.ft. home would do most. One person breathing in a home with less than 50 cfm of fresh air would measure +650 ppm CO2 with 450 ppm outside CO2. You could pick any air change rate you want. When the wind blows winter average, +- 7 mph, most homes do not need fresh air. One person would not release enough CO2 to trigger fresh air ventilation. Calm summer nights with windows closed, the fresh air change rate slows to a fresh air change in +12 hours in most well built homes. One person would trigger the fresh air ventilation setting of +650 ppm CO2.

CO2 controllers are available for <$200 from many. Fresh filtered air change when occupied and with inadequate natural is not expensive. In green grass climates, add humidification and dehumidification maintaining +40% and <55% RH for comfort and health provides a near perfect indoor condition. Most climates require <$200 conditioning per year for common houses.

Occupants will grow older and be more healthy and comfortable!
Hard to get this simple message across.

Regards Teddy Bear

[randyf]

hi
I know this is an old thread but wanted to ask you some quesitons since it seems you know a lot about the subject. I recently got one of the cheap detectors on amazon and am seeing high vocs. Interestingly they increase dramatically as you go up floors. The basement averages .5 mg/m^3. First floor is 3 mg/m^3. Second floor is 6 mg/m^3. The formaldehyde, pm2.5, and pm10 are low. I plan on getting test from one of the companys you have recommended to verify. Do you have any insight into why VOCs would be higher on upper floors? Also is it possible even though total vocs are high, that the harmful ones are not necessarily high? The outdoor air measures around .1 which is not zero but seems pretty low. I am within a mile or 2 of a natural gas compressor station, which puts out a lot of vocs.

Don't mean to be glib but your levels are reading higher because your concentrations are higher. I've noticed the same thing in my 3 level condo and I believe it's related to the location of my attic. It could also (possibly?) related to the the stack effect this time of year.

But keep the following in mind:
1. Consumer VOC meters are notoriously inaccurate for absolute readings, but I've found them useful for relative readings. In other words the .5, .3, .6 readings may my not correlate to the real "absolute" levels but the differences at different location are probably loosely indicative.
I've got about 6 different consumer meters and I can place them side by side and the absolute readings can vary significantly but they will all indicate when levels are going up or down.
What meter are you using?

2. What's under appreciated about VOCs is that most boil (evaporate) between 50 - 250F. So most of what gets into the air is off gassing from liquids/solids on surfaces. Ventilating is great and can reduce levels quickly to nominal levels. Unfortunately levels will rise again when I close windows and turn fans off. Until the VOCs on surfaces are eliminated you will have a problem.

3. This time of year in Texas, especially after a cold snap, levels will decrease significantly due to the stack effect. Outside air is automatically circulated lowering the VOCs in the air, only to rise again when it warms up ~>75F or so.

4. OSHA, NIOSH, ACGIH have characterized hundreds of VOCs for maximize safety limits. See:
https://www.osha.gov/annotated-pels/table-z-1

I was astounded and a bit relived when I first saw the high amounts that government standards considers without effect.
Of course some VOCs are problems at lower levels - benzene, formaldehyde, Naphthalene, Acetaldehyde and a fair amount of others, but I was amazed at the high quantities that government regulating bodies have Oked for most VOCs.

5. The more immediate problems with VOCs in homes/offices is not extreme levels, but the effect on general well being -even when VOCs can't be detected by the nose.

A group out of Havard slightly increased VOCs (.5mg/m^3) levels on some days. On other days fresh air was circulated. The study was double blind so neither workers or researchers new if it was a fresh air day or a slight VOC day. The office workers were given neuro psy test for stuff like reaction speed, executive function and such. VOCs levels were so low no one could smell them. Testing results was always significantly better when VOCs were low. Subjectively most folks didn't notice any difference, but they weren't performing at their potential.

Take home message - Even low level of Vocs reduce quality of life.
Ref: https://hbr.org/2017/03/research-sta...ess-productive

6. I've found Heavey carbon canister and blowers incredible effective and low cost in quickly lowering levels when you can't circulate fresh air.
One company I've used is Terrabloom - https://terra-bloom.com/ another is Vortex.
These are significantly less expense and more effective than whats offered in so called home air purifiers. Most products sold as Home Air Purifier are only effective for particulates and even when they claim otherwise
They are ineffective for "odors". They do not have enough carbon to be useful.

7. Home Air Check is no longer providing GC/MS test kits directly to the public, but require kits be purchased through 3rd parties. This does nothing but significantly increase cost (2x- 3x) with no added value.
The home owner gets screwed.

I'll be interested in your progress.

[teddy bear]

Don't mean to be glib but your levels are reading higher because your concentrations are higher. I've noticed the same thing in my 3 level condo and I believe it's related to the location of my attic. It could also (possibly?) related to the the stack effect this time of year.

But keep the following in mind:
1. Consumer VOC meters are notoriously inaccurate for absolute readings, but I've found them useful for relative readings. In other words the .5, .3, .6 readings may my not correlate to the real "absolute" levels but the differences at different location are probably loosely indicative.
I've got about 6 different consumer meters and I can place them side by side and the absolute readings can vary significantly but they will all indicate when levels are going up or down.
What meter are you using?

2. What's under appreciated about VOCs is that most boil (evaporate) between 50 - 250F. So most of what gets into the air is off gassing from liquids/solids on surfaces. Ventilating is great and can reduce levels quickly to nominal levels. Unfortunately levels will rise again when I close windows and turn fans off. Until the VOCs on surfaces are eliminated you will have a problem.

3. This time of year in Texas, especially after a cold snap, levels will decrease significantly due to the stack effect. Outside air is automatically circulated lowering the VOCs in the air, only to rise again when it warms up ~>75F or so.

4. OSHA, NIOSH, ACGIH have characterized hundreds of VOCs for maximize safety limits. See:
https://www.osha.gov/annotated-pels/table-z-1

I was astounded and a bit relived when I first saw the high amounts that government standards considers without effect.
Of course some VOCs are problems at lower levels - benzene, formaldehyde, Naphthalene, Acetaldehyde and a fair amount of others, but I was amazed at the high quantities that government regulating bodies have Oked for most VOCs.

5. The more immediate problems with VOCs in homes/offices is not extreme levels, but the effect on general well being -even when VOCs can't be detected by the nose.

A group out of Havard slightly increased VOCs (.5mg/m^3) levels on some days. On other days fresh air was circulated. The study was double blind so neither workers or researchers new if it was a fresh air day or a slight VOC day. The office workers were given neuro psy test for stuff like reaction speed, executive function and such. VOCs levels were so low no one could smell them. Testing results was always significantly better when VOCs were low. Subjectively most folks didn't notice any difference, but they weren't performing at their potential.

Take home message - Even low level of Vocs reduce quality of life.
Ref: https://hbr.org/2017/03/research-sta...ess-productive

6. I've found Heavey carbon canister and blowers incredible effective and low cost in quickly lowering levels when you can't circulate fresh air.
One company I've used is Terrabloom - https://terra-bloom.com/ another is Vortex.
These are significantly less expense and more effective than whats offered in so called home air purifiers. Most products sold as Home Air Purifier are only effective for particulates and even when they claim otherwise
They are ineffective for "odors". They do not have enough carbon to be useful.

7. Home Air Check is no longer providing GC/MS test kits directly to the public, but require kits be purchased through 3rd parties. This does nothing but significantly increase cost (2x- 3x) with no added value.
The home owner gets screwed.

I'll be interested in your progress.

Thank you for a very interesting post. So many things can effect the quality of and length of life. O2/CO2 levels in the air we breathe, the food we eat/drink, our exercise, and metal activity. My point has been that we should optimize the obvious variables. Covid has also shown the life shortening effects of less than optimum conditions.

More comfort and longer life, keep it coming!

Regards Teddy Bear

[randyf]

Teddy - Thanks so much for your comments - means a lot to me coming from you.

In 2015 I purchased a condo with unusual "smells".
I wasn't moving in for 3 months after I closed the purchase and was told "don't worry, the odors will resolve".
Six weeks before I move in I called the original home inspector with my concerns. He came by said - "Don't worry all is OK, just new construction smells they will fade".
I assumed (ass out me and you) he knew what he was talking about. Why not, he was a "professional" after all. Beside I wanted to believe him.

Moved in 6 weeks later assured all was OK, but it wasn't. The place still didn't smell right and I felt lousy.
At that point I discovered "Home Air Check" and order a GC/MS lab test - the gold standard. My levels came back as 2200ng/liter.
That's very high. You want levels <500 and preferably <200. I was pissed! I have some experience with researching academic research and started familiarizing myself with the topic.

Around this time I discovered HVAC-Talk and the "Indoor Air Quality" forum and soon discovered "Bear Rules" from some guy that seemed to know what he was talking about in a real world evidence based manner.

I soon discovered my AC blower was variable speed which my controller didn't implement. I got a controller that did and now keep my RH levels <50 (located in central Texas with summer dew points in the mid 70s). I couldn't bring in fresh air due to HOA constraints but purchased a couple of hygrometers and a CO2 meter (CO2meters.com) to keep a close eye on humidity and air exchange rates. Big improvements followed. Learned about the stack effect and observed in real time what a huge difference makes this time of year.

As a non- AC professional I am really thankful for Teddy's constant reminders of these basic simple universal principles.

Thanks!

[teddy bear]

Teddy - Thanks so much for your comments - means a lot to me coming from you.

In 2015 I purchased a condo with unusual "smells".
I wasn't moving in for 3 months after I closed the purchase and was told "don't worry, the odors will resolve".
Six weeks before I move in I called the original home inspector with my concerns. He came by said - "Don't worry all is OK, just new construction smells they will fade".
I assumed (ass out me and you) he knew what he was talking about. Why not, he was a "professional" after all. Beside I wanted to believe him.

Moved in 6 weeks later assured all was OK, but it wasn't. The place still didn't smell right and I felt lousy.
At that point I discovered "Home Air Check" and order a GC/MS lab test - the gold standard. My levels came back as 2200ng/liter.
That's very high. You want levels <500 and preferably <200. I was pissed! I have some experience with researching academic research and started familiarizing myself with the topic.

Around this time I discovered HVAC-Talk and the "Indoor Air Quality" forum and soon discovered "Bear Rules" from some guy that seemed to know what he was talking about in a real world evidence based manner.

I soon discovered my AC blower was variable speed which my controller didn't implement. I got a controller that did and now keep my RH levels <50 (located in central Texas with summer dew points in the mid 70s). I couldn't bring in fresh air due to HOA constraints but purchased a couple of hygrometers and a CO2 meter (CO2meters.com) to keep a close eye on humidity and air exchange rates. Big improvements followed. Learned about the stack effect and observed in real time what a huge difference makes this time of year.

As a non- AC professional I am really thankful for Teddy's constant reminders of these basic simple universal principles.

Thanks!

Thank you for the kind words. Your comments mean a lot all of us that attempt to pass on our experiences and possible changes that may improve our overall air quality of life.

The level of CO2 is an indicator of the amount of outdoor fresh air passing through the home occupied space when the number of occupants in the space considered.
What range of CO2 levels verses the number of occupants have you observed? Like to compare high stack/wind verses mild weather/calm levels. You may consider a small fan in a window or ??, if you show less than a fresh air change in more than 6 hours.

Situations like yours often result in a fresh air change in +12 hours for long periods. With 450 ppm outside CO2 levels, A single occupant with 650 ppm CO2 is getting 50 cfm of fresh air per occupant. This assumes perfect mixing of fresh air and CO2 according to GE meters info. In a 1,500 sq.ft. space with 9 ft. ceilings at 50 cfm fresh air would be 27,000 mins. per air change, about 10 hours for an air change. Ideal would be 3-5 hours.

Let us know the range of CO2 that you are seeing during the weather extremes of recent years.

Thanks again for the info you shared. It gives us insight the extent of these problems/opportunities to improve health and comfort.

Regards Teddy Bear

[blivengo]

randy, Thanks for the reply. Im using a meter made by VSON. I ordered a home air check test from one of there resellers and it was $185 for the voc and mold test, so not too bad. Westinghouse makes a newer air purifier that claims to remove vocs with a newer tech called ncco, with some users reporting good results measuring with meters. Other than that I am thinking of getting an ERV put in. I have a humidity issue in the summer (AC dosent stay on long enough to get the humidity down) and i think that might help humidity as well.

[randyf]

hi
The basement averages .5 mg/m^3. First floor is 3 mg/m^3. Second floor is 6 mg/m^3.

I misread your post earlier - sorry. .5 mg/m^3 is acceptable making some reasonable assumption.
But - 3mg/m^3 and 6mg/m^3 are very high and should be investigated. Please keep in mind the limitations of low cost consumer MOS sensor mentioned. If the high readings are true, I would expect these value to be noticeable
Suggestions:
0. Take your meter to other enclosed spaces and see if you get those high readings. Is so that's good indicator that the meter is faulty . Open some Windows and exhaust some air out. See if high levels go down. Make sure you are not taking readings during/after cooking.
1. Buy a better low cost MOS sensor - I use the Temtop M10
2. Rent a ppbPID meter. I recommend the ION Science ppb
3. Arrange a GC/MS lab test through "Home Air Check" or https://www.fikeanalytical.com/.

[randyf]

randy, Thanks for the reply. Im using a meter made by VSON. I ordered a home air check test from one of there resellers and it was $185 for the voc and mold test, so not too bad. Westinghouse makes a newer air purifier that claims to remove vocs with a newer tech called ncco, with some users reporting good results measuring with meters. Other than that I am thinking of getting an ERV put in. I have a humidity issue in the summer (AC dosent stay on long enough to get the humidity down) and i think that might help humidity as well.

I've tested the Westinghouse purifier recently for Vocs reduction. It didn't work and generated and odor to boot.

Just posted some suggestions.

Here's something you can try immediately to see if the increased level's are real.
1. Open Windows/Doors and force fresh air in and out and see if level go down in few minutes.
2. if levels do go down close everything up and see if levels come back up.
3. Take your meter to other homes and note readings.

I'm interested in how all this develops.

Thanks

[randyf]

Westinghouse makes a newer air purifier that claims to remove vocs with a newer tech called ncco, with some users reporting good results measuring with meters. .

If you could send a link with user testing of the Westinghouse unit I'd be appreciative.

I tested a few weeks ago and did record any differences. I returned the unit to Amazon.

If you levels are indeed as high as your meter is reporting I'd recommend getting a heavy carbon canister and blower from "Terrabloom" or "Vortex". Ive consistently seen reduction of 70% - 90% in minutes.