ERV is the abbreviation for Energy Recovery Ventilator. I recently saw a newer design in the form of a short window AC unit.
The box fan solution (not entirely spelled out) is called the Corsi-Rosenthal Box. One can find a lot of youtube videos on this. You just need a 20x20 inch box fan, four 20x20 HVAC filters, duct tape, and maybe the cardboard box the fan came in. I would use *thicker* filters (> 1 inch) with a high MERV rating.
Thanks for the extra notes, John! Great callout about the Corsi-Rosenthal Box - we didn't get a chance to cover that on the podcast, so thank you for sharing here. It's a great low-cost solution.
Such a great conversation! This line really got me: "All of them looked at me with raised eyebrows and were suddenly scared."
I've had a lot of success in my climate activism with helping people make the connection between indoor and outdoor air. Indoor often hits home first due to the health risks, but anything people can do to electrify their homes will both help their lungs and the climate.
Currently, I'm doing a program here in IL with Faith in Place to help people test their indoor air quality. Afterwards, they also get a free induction cooktop to help reduce their indoor emissions.
The movement for clean indoor air will not succeed so long as we continue to memory-hole COVID with past-tensing postmortem language like "during the pandemic", "during COVID", "after COVID", "lessons learned", etc. COVID never went away. In fact, since removal of all mitigations, wastewater shows a continuing pattern of two annual surges (summer and winter), with baseline infection rates rising year over year during lulls. SARS-CoV-2 still poses dire threats of disability and death--yes, to children, yes, to the vaccinated. The seriousness of these threats must be re-acknowledged and faced head-on if we are to galvanize air quality improvement efforts.
Benzene and nitrous oxide from gas stoves, yum. I wonder if this podcast would be something to maybe share with teacher's unions? And now I have to go out and buy an air quality monitor.
One note of caution. More and more outside air (OA) is not always the best, even with great filtration. Not just because of the energy to condition it. In the winter in cold climates, a lot of OA causes the indoor air to become too dry. The dry air dries out our mucus membranes, leaving us more susceptible to all those germs our fellow occupants are hacking out. Humidifiers are always an option, but they are one of the most trouble prone HVAC components and use energy themselves.
Because of the way their HVAC has been designed, many offices have overall excessive OA, BUT at the same time inadequate OA and very high CO2 in conference and meeting rooms. "Optimizing" for this is good fun for HVAC control vendors, designers and installers.
Folks should be aware, some aspects of IAQ have improved substantially in the last 30 years. First, thanks to regs in CA which expanded to other jurisdictions, and LEED credits and prerequisites, VOCs in construction materials dropped drastically. Less "new building smell" in pretty much all buildings. Also rules have made contractors seal off duct systems during construction so they don't regurgitate dust from sheetrock, wood and whatever weirder stuff has been cut, shaved and sanded.
In homes there was a period where some ill-advised combinations of envelope and HVAC design led to mold but most folks in the construction biz now understand how to avoid this.
If anyone is getting a new furnace or replacing one with a central HP, get a 4 or 5" filter box so you can fit a MERV 13 filter in w/o excess pressure drop. If utilizing the 1" high MERV filters, make sure to replace them every 2-3 months to avoid creating so much pressure drop you burn out the furnace fan. I still have a furnace but it's some super modulating 99% w/3 speed fan and I set it to run on low speed (20W) continuously even if there is no heat need. With the filter it does a great job of keeping the PMs down and mixing the air and evening out temps and RH.
Hi All: Thanks for this critical discussion. I researched MERV ratings for my large Brooklyn coop well before covid, and the community decided to use MERV 11s. During the height of the Pandemic, there were notable researchers providing essential information for those of us who were curious. One was Richard Corsi (UC Davis). Another was Joey Fox, trained at Harvard, teaching in Canada. Kimberley Prather, an atmospheric scientist at Scripps, was doing amazing work and was pilloried for her findings when she proved early on that C19 was aerosolized and not droplet-based. I admired the work of Lindsey Marr, too, and because of her, I watched this segment of '60 Minutes' :https://www.paramountplus.com/shows/video/jS6vCS32uWnKpTtf_j_uFLIIlw0R0Qgd/?ftag=CNM-00-10abb6c , though I'm now boycotting CBS and Paramount. So people were doing work--perhaps they lacked a central leader. Dr. Lagoudas, it's interesting that none of them were involved in the UN conference. I hope you're coordinating with them now.
Thank you, Georgia and David, for this podcast--so very insightful! I now have AQMs in each bedroom and a mobile one I carry to work.
Please consider connecting with Austin Riesenberger and his startup effort to create https://swervair.com/. He would likely benefit from your engineering expertise, investor assistance, and other insights to better indoor air quality.
Thank you so much for taking the trouble to reply and to provide information and guidance on what I should do to reduce the amount of particulates entering my house during smog episodes. You’re brilliant, and your advice is good and appreciated.
"may be the biggest opportunity to improve public health in the 21st century."
That's a strong statement that seems like it should be addressed first at the start of the pod. Off the top of my head, I can think of two opportunities that seem like they should be larger:
1) Tax sugar.
2) Pay people to exercise. (Consider it a form of UBI.)
On the other hand, if people are serious about cleaning indoor air to greatly reduce airborne viruses, 40,000 fewer influenza deaths per year is nothing to sneeze at...
Thanks for that point! Yes, it's hard to compare apples-to-apples with different public health interventions, but reducing airborne pollutants will have a major impact on overall health of the population. Heart disease, cognition, asthma, influenza, and covid - it's a long list. But rightly so that other interventions (like addressing obesity!) are priorities as well. Happy to share more (find me on linkedIn)
Hi David and Georgia, - I read the entire transcript of your interview but nowhere did I find a word of advice to ordinary house owners about what they can to to reduce particulates and CO2 entering their homes. I live in a suburban area prone to smog during cold weather with overcast cloud, when all my neighbours turn on their boilers or burn coal to heat their houses and I can smell the pollution getting in through my windows. I know my health is put at risk during these episodes, so could you please advise on limiting the amount of particulates etc that get in through my windows. Are there filters you can put on windows to limit the particulates getting in? You spent an hour talking but you never once addressed this crucial question. I hope you can shed some practical light on this question, given that your discussion failed utterly to address it.
Thanks for that point, Coilin. We sure tried to pack in a lot during the hour and didn't get much time for homeowner advice! The top line recommendations: 1) use a portable air purifier in your home to filter the air indoors; 2) get an air quality monitor (that includes readings of PM2.5) to get a sense of when you have poor air quality (greater than 10-20 ug/m3); 3) potentially seal your windows if there are major air leaks. Additionally, if you have mechanical ventilation (HVAC), upgrade your filters to MERV 11 or higher, if possible, and run the system at "ON" as needed.
Just a couple of notes:
ERV is the abbreviation for Energy Recovery Ventilator. I recently saw a newer design in the form of a short window AC unit.
The box fan solution (not entirely spelled out) is called the Corsi-Rosenthal Box. One can find a lot of youtube videos on this. You just need a 20x20 inch box fan, four 20x20 HVAC filters, duct tape, and maybe the cardboard box the fan came in. I would use *thicker* filters (> 1 inch) with a high MERV rating.
Huge energy efficiency gains can be made to the standard box fan Corsi Rosenthal box by using five to six PC fans instead, mounted to a solid piece of wood or pvc. It's about 1/4 of the energy and noise! https://www.texairfilters.com/an-easy-to-build-corsi-rosenthal-box-using-modular-pc-fan-systems/
Thanks for the extra notes, John! Great callout about the Corsi-Rosenthal Box - we didn't get a chance to cover that on the podcast, so thank you for sharing here. It's a great low-cost solution.
Such a great conversation! This line really got me: "All of them looked at me with raised eyebrows and were suddenly scared."
I've had a lot of success in my climate activism with helping people make the connection between indoor and outdoor air. Indoor often hits home first due to the health risks, but anything people can do to electrify their homes will both help their lungs and the climate.
Currently, I'm doing a program here in IL with Faith in Place to help people test their indoor air quality. Afterwards, they also get a free induction cooktop to help reduce their indoor emissions.
So great to hear about your program! Best of luck in IL and don't hesitate to get in touch (can drop me a message in LinkedIn or online)
The movement for clean indoor air will not succeed so long as we continue to memory-hole COVID with past-tensing postmortem language like "during the pandemic", "during COVID", "after COVID", "lessons learned", etc. COVID never went away. In fact, since removal of all mitigations, wastewater shows a continuing pattern of two annual surges (summer and winter), with baseline infection rates rising year over year during lulls. SARS-CoV-2 still poses dire threats of disability and death--yes, to children, yes, to the vaccinated. The seriousness of these threats must be re-acknowledged and faced head-on if we are to galvanize air quality improvement efforts.
Benzene and nitrous oxide from gas stoves, yum. I wonder if this podcast would be something to maybe share with teacher's unions? And now I have to go out and buy an air quality monitor.
Yes, there is so much coming from indoor combustion! Great idea re: sharing with teacher's unions.
One note of caution. More and more outside air (OA) is not always the best, even with great filtration. Not just because of the energy to condition it. In the winter in cold climates, a lot of OA causes the indoor air to become too dry. The dry air dries out our mucus membranes, leaving us more susceptible to all those germs our fellow occupants are hacking out. Humidifiers are always an option, but they are one of the most trouble prone HVAC components and use energy themselves.
Because of the way their HVAC has been designed, many offices have overall excessive OA, BUT at the same time inadequate OA and very high CO2 in conference and meeting rooms. "Optimizing" for this is good fun for HVAC control vendors, designers and installers.
Folks should be aware, some aspects of IAQ have improved substantially in the last 30 years. First, thanks to regs in CA which expanded to other jurisdictions, and LEED credits and prerequisites, VOCs in construction materials dropped drastically. Less "new building smell" in pretty much all buildings. Also rules have made contractors seal off duct systems during construction so they don't regurgitate dust from sheetrock, wood and whatever weirder stuff has been cut, shaved and sanded.
In homes there was a period where some ill-advised combinations of envelope and HVAC design led to mold but most folks in the construction biz now understand how to avoid this.
If anyone is getting a new furnace or replacing one with a central HP, get a 4 or 5" filter box so you can fit a MERV 13 filter in w/o excess pressure drop. If utilizing the 1" high MERV filters, make sure to replace them every 2-3 months to avoid creating so much pressure drop you burn out the furnace fan. I still have a furnace but it's some super modulating 99% w/3 speed fan and I set it to run on low speed (20W) continuously even if there is no heat need. With the filter it does a great job of keeping the PMs down and mixing the air and evening out temps and RH.
Hi All: Thanks for this critical discussion. I researched MERV ratings for my large Brooklyn coop well before covid, and the community decided to use MERV 11s. During the height of the Pandemic, there were notable researchers providing essential information for those of us who were curious. One was Richard Corsi (UC Davis). Another was Joey Fox, trained at Harvard, teaching in Canada. Kimberley Prather, an atmospheric scientist at Scripps, was doing amazing work and was pilloried for her findings when she proved early on that C19 was aerosolized and not droplet-based. I admired the work of Lindsey Marr, too, and because of her, I watched this segment of '60 Minutes' :https://www.paramountplus.com/shows/video/jS6vCS32uWnKpTtf_j_uFLIIlw0R0Qgd/?ftag=CNM-00-10abb6c , though I'm now boycotting CBS and Paramount. So people were doing work--perhaps they lacked a central leader. Dr. Lagoudas, it's interesting that none of them were involved in the UN conference. I hope you're coordinating with them now.
Thank you, Georgia and David, for this podcast--so very insightful! I now have AQMs in each bedroom and a mobile one I carry to work.
Please consider connecting with Austin Riesenberger and his startup effort to create https://swervair.com/. He would likely benefit from your engineering expertise, investor assistance, and other insights to better indoor air quality.
Hi Georgia (and David),
Thank you so much for taking the trouble to reply and to provide information and guidance on what I should do to reduce the amount of particulates entering my house during smog episodes. You’re brilliant, and your advice is good and appreciated.
Keep up the great work!
Best wishes
Coilin
"may be the biggest opportunity to improve public health in the 21st century."
That's a strong statement that seems like it should be addressed first at the start of the pod. Off the top of my head, I can think of two opportunities that seem like they should be larger:
1) Tax sugar.
2) Pay people to exercise. (Consider it a form of UBI.)
On the other hand, if people are serious about cleaning indoor air to greatly reduce airborne viruses, 40,000 fewer influenza deaths per year is nothing to sneeze at...
Thanks for that point! Yes, it's hard to compare apples-to-apples with different public health interventions, but reducing airborne pollutants will have a major impact on overall health of the population. Heart disease, cognition, asthma, influenza, and covid - it's a long list. But rightly so that other interventions (like addressing obesity!) are priorities as well. Happy to share more (find me on linkedIn)
Hi David and Georgia, - I read the entire transcript of your interview but nowhere did I find a word of advice to ordinary house owners about what they can to to reduce particulates and CO2 entering their homes. I live in a suburban area prone to smog during cold weather with overcast cloud, when all my neighbours turn on their boilers or burn coal to heat their houses and I can smell the pollution getting in through my windows. I know my health is put at risk during these episodes, so could you please advise on limiting the amount of particulates etc that get in through my windows. Are there filters you can put on windows to limit the particulates getting in? You spent an hour talking but you never once addressed this crucial question. I hope you can shed some practical light on this question, given that your discussion failed utterly to address it.
Thanks for that point, Coilin. We sure tried to pack in a lot during the hour and didn't get much time for homeowner advice! The top line recommendations: 1) use a portable air purifier in your home to filter the air indoors; 2) get an air quality monitor (that includes readings of PM2.5) to get a sense of when you have poor air quality (greater than 10-20 ug/m3); 3) potentially seal your windows if there are major air leaks. Additionally, if you have mechanical ventilation (HVAC), upgrade your filters to MERV 11 or higher, if possible, and run the system at "ON" as needed.
EPA has some resources: https://www.epa.gov/indoor-air-quality-iaq/guide-air-cleaners-home
Or to cut to the chase, the indoor pollution by nanoplastics - the most dangerous airborne pollutants - is 8 times higher than whatever it is outside.
And not cleared by even the most sophisticated filters.
The science behind this has been explained in OurNewRealityThePlasticene