Showing posts with label IAQ. Show all posts
Showing posts with label IAQ. Show all posts

Thursday, August 3, 2023

Odor Hunter Extraordinaire Cliff the Z Man Zlotnick


Cliff the Z Man Zlotnick on IAQ Radio

If you suspect a dead animal hiding in your walls (because you're house smells like a dead animal), here's what Cliff the Z Man Zlotnick does, as described back in 2007 on the IAQ Radio Show:

Put a handful of raw ground beef in a garbage bag in a wastebasket and leave it outside. Within minutes, flies will be attracted to the meat. That's when you close up the garbage bag, bring it inside, open it back up, and watch as the flies fly straight to the problem. The gases that emit from a dead animal pass through the wall itself, and the flies can smell that. 


Mandatory shout out to Avery Gilbert and his I Smell Dead People Column on his First Nerve blog (or his newer substack).

Wednesday, November 30, 2022

Living With Friends


Above we see a microscopic view of the Paenibacillus bacteria, found in coffee machines and where coffee is prepared. It's been used as a probiotic for both chickens and bees, and might have something to do with the idea that coffee is good for your health. 

But that's just coffee. Onto the real story -- nobody lives alone, and that includes even those of us who don't live with other people. We're talking about the vast array of microbes that share our domestic biome with us. They outnumber us by the billions (uncountable really) and could have a strong influence on our health, maybe even our behavior (looking at you Toxoplasmosis), all by way of the mediating effects between our microbiome and our immune system. And they smell. Not all of them, but where there's life, there's smells. It's our own domestic ecology of smells.  

Each one of us affects the microbiome we live with, depending on who we are, what we eat, what we do for work and in our spare time, how we clean, how often and how thoroughly we clean, ad infinitum. The home is a dynamic place, and very different from a scientific laboratory, in almost every way, and so we don't have a good idea of what's happening in our homes, not on a biological basis, and not even on a chemical basis. 

And then came the HOME house, the HOME Chem model house, a chemical-lab-house, put together by 60 scientists from 13 universities in Austin, Texas circa 2020. They do regular-house things and measure the chemical profile of the air inside the home over time while they cook, clean, eat, sleep. It might sound mundane, but it's the first time we're getting real world indoor air quality data from the domestic frontier.

Most air quality data comes from outside air. We haven't been thinking about the indoor air for very long, and much less resources and scientific inquiry have been devoted to it. The HOME project gives us the first glimpse of what's really happening to our indoor environment while we live there.  


With roommates, it's all about chemistry, molecularly speaking
Jun 2022, phys.org

An experimental test home was erected in Austin, Texas during the summer of 2018. The house was designed for ordinary use and included bathrooms, a kitchen, gathering and work areas. Overnight stays were prohibited, but 45 study participants, plus visitors, spent time in the house, occupying it for approximately six hours per day for 26 days, during which they performed scripted activities, such as cooking, cleaning and socializing.

The house was deep cleaned with a bleach solution. Nonetheless, researchers said traces of molecules associated with humans were still present. After almost of month of human occupation, the house was alive with molecular and microbial abundance and diversity, albeit unevenly distributed.

Not surprisingly, the kitchen and toilet were hotspots of molecular and microbial diversity, though numbers fluctuated with surface cleaning and sanitation. "It appears that, even when a subset of chemistry is removed because of the cleaning, it is only temporary and/or partial, as the sum total of cleaning and human activities overall results in an increase in accumulation of richer chemistry," the authors wrote.

via University of California San Diego, Colorado State (Delphine Farmer), and University of Colorado: Alexander A. Aksenov et al, The molecular impact of life in an indoor environment, Science Advances (2022). DOI: 10.1126/sciadv.abn8016


Here's more links on HOME:

And here's some information on how bad we are at perceiving air quality indoors:
  • Teachers did not accurately perceive mechanical ventilation sufficiency
  • Air quality and temperature are conflated
  • Dramatic difference in IAQ perception (but not quality) in summer vs winter
  • Occupants misperceive temperature as a proxy for indoor air quality; they think cooler air is better, and confuse warm air with "stuffy, stale" air
  • Teachers in classrooms with worse ventilation were more satisfied with classroom temperature
  • Occupants don't understand how the systems work, and think incoming cold air in winter is a defect, for example (when in fact it is the system adding fresh air to the mix); they then say the system isn't working, and therefore they must have bad IAQ; they also think the only time the system brings fresh air is when the AC is on, which is the complete opposite of what's happening
Source: Pistochini T, Mande C, Modera M, et al. Improving Ventilation and Indoor Environmental Quality in California K-12 Schools (CEC-500- 2020-049). Sacramento, CA: California Energy Commission; 2020. https://www.energy.ca.gov/publications/2020/improving-ventilation-and-indoor-environmental-quality-california-schools

Wednesday, August 12, 2020

Clean Air Beware

 

Just when you thought you knew what to do, you don't.

 

Ventilation is good (and a necessary part of controlling an airborne virus, by the way), but opening windows will not remove the chemicals from most homes, at least according to this work done with the HOME Chem model house.

 

Our indoor environments are filled with the chemicals that offgas from just about everything that surrounds us, from body care products to scented candles to building materials. Cleaning products are a major culprit here, and also an important consideration while trying to combat a global pandemic via the war against germs, aka chemical disinfectants, aka indoor environmental chemical warfare.

 

For almost any product you bring into your home, or any activity you perform there, chemicals are released into the air. Not all chemicals are bad, but some of them are. The problem is not even in identifying the "bad" things in the air, but in measuring how much things accumulate, no matter what they are -- everything is bad at the right dose.

 

Opening the windows is the most straightforward and effective way of reducing these concentrations. The problem is that at some point those windows must be closed. Experiments done in the "chem house" show that the concentrations of typical chemicals found indoors do drop precipitously when we open the windows.

 

But surprise -- a few minutes after they're closed, the concentrations go right back up to baseline.


The idea is that the chemicals cling to the walls, likely in the macro- and microscopic nooks and crannies on the surface. They act like reservoirs. Volatile organic compounds will offgas into the room, and especially during cleaning activities for example, where they settle onto those surface microtextures, and then re-volatilize into the air continuously.

 

In conclusion, opening windows is good for flushing chemicals out of the indoor air temporarily, but the real effort must be put into keeping them out in the first place. (Sorry Clorox wipes, I’m looking at you, don't act like you don't offgas.)

 

Image source: The Broom Maker, Victor on Flickr, 2019

 

Post Script:

What produces more voc’s, spraying a perfume on your wrist once a day or cleaning your house with a surface disinfectant once a week? *First of all, cleaning and disinfecting are not the same thing, and second of all, you’re probably over-disinfecting.

 

Notes:

Opening the window in your home will not flush out the chemicals in the air

Feb 2020, phys.org

https://phys.org/news/2020-02-window-home-flush-chemicals-air.html

 

Chen Wang et al. Surface reservoirs dominate dynamic gas-surface partitioning of many indoor air constituents, Science Advances (2020). DOI: 10.1126/sciadv.aay8973

http://dx.doi.org/10.1126/sciadv.aay8973

 

A good follow up:

Organic compounds in indoor air like to accumulate in paint

May 2020, Indoor Chem Blog

https://indoorchem.org/2020/05/paint/

 

Measurements and modeling of absorptive partitioning of volatile organic compounds to painted surfaces. Algrim, L. B., Pagonis, D., de Gouw, J. A.,  Jimenez, J. L.,  and Ziemann P. J. Indoor Air, 2020. 00; 1-12 doi.org/10.1111/ina.12654

https://doi.org/10.1111/ina.12654

 

Further reading:

HOME Chem - House Observations of Microbial and Environmental Chemistry

University of Colorado and CU Boulder

https://indoorchem.org/projects/homechem/

 

ISIAQ - International Society of Indoor Air Quality and Climate

https://iaiq.org

 

Thursday, December 19, 2019

Gaia Bots and Plant Pots





It was long before artificial turf and breast implants that humans began losing their connection with nature.

There is a long history of our love affair with Mother Earth, and two variations on this theme for those interested in the subject could be the American Frontier and the English Garden (both circa 1700-1800's). In the former, the West was a force to be feared, explored, and eventually dominated. In the latter, the Garden was a symbol of the picturesque, idyllic and meandering qualities of nature, albeit designed and maintained by human intervention.

The picture-perfect English Garden isn't much different from pretty much anywhere else on Earth – it's all a hybrid. Everything on this planet has in some way been shaped by us. You want evidence? How about the serious debate by geologists trying to demarcate the beginning of the Anthropocene as a geologic epoch. We've been terraforming this place since the dawn of agriculture and have no plans on stopping (carbon dioxide be damned).

This is quite a lofty intro for a post about houseplants. But this is where we start because the myth that "houseplants filter indoor air" is tenacious. It's also a great example of what makes a meme sticky, because it's simple, easy to understand, and common to everyone. It's also wrong.

You can't blame us. We want the outside inside; we're all biophiles! We want it to be true that filling our house with plants will enhance our indoor environment in scientifically-supported, quantifiable ways.

But it's fake news. And in the manner of all news that is fake, the idea that houseplants clean our indoor air is not absolutely wrong. They do clean the air, just not enough to make a difference.

I mean, if you were on a spaceship, where ev-er-y-thing makes a difference, then sure. That's where this all started. Studies done for NASA showed that they could use plants as part of a larger air-cleaning strategy. And there you have it, memetic gold.

(You know what's not mememtically robust? The fact that it's the soil microbes doing all the dirty work, not the plants themselves!)

The bottom line is that the amount of clean, fresh air that can be delivered by a typical mechanical exhaust ventilation system is a few magnitudes more than that coming from our vegetal ancestors. Or, if you really insist on bringing the outside in, open a window.

-image source link

Post Script
We start domesticating plants 10,000 years ago as a part of the Neolithic or Agricultural revolution. The ancients of Egypt, India, China, Greece and Rome all put plants in pots, but most of these were used to decorate outdoor spaces (think Hanging Gardens of Babylon). We can trace the practice of using houseplants back to the 1600's with a book called The Garden of Eden. But Buckminster Fuller's 1967 Biosphere might have a lot more to do with their current ubiquity.

Post Post Script
Our indoor space as urban dwellers is vastly different than that of jungle huts. Obviously. But what you may not have known is that our walls and windows trap so much of our own metabolic excreta that we live in higher concentrations of our own filth than someone in a thatched hut.

You can’t really measure “filth” in this context, so the above statement is more hyperbole than fact. However, this collaboration between the Microbiology and Anthropology Departments at Rutgers University, New Jersey, painted a good comparative picture of our respective indoor environments.

They studied a remote Peruvian jungle village of thatched huts with no walls, a Peruvian rural town with wooden houses sans indoor plumbing, a Peruvian city of 400,000 residents, and the two million-strong metropolis of Manaus, Brazil.

They found that we have a higher diversity of chemicals from medications and cleaning products and of fungi associated with human skin, the mouth and the gut, whereas the rural and jungle homes had a greater variety of outdoor-associated bacteria and fungi typically found in water and soil.

This is because the walls themselves trap all this stuff as it floats in the indoor air. We also have warmer, wetter air than a jungle hut, as well as less sunlight and less fresh-air exchange. This plus the tons of dead skin cells we leave lying around all make a great incubation-chamber for fungi. So despite the fact that urban dwellers clean more frequently, their indoor environment is teeming with micro-organisms that live in and on our bodies.

The end result is that our homes, in the more urban areas, and in more modern times, are more like the human body than the body of Mother Earth.

Home chemical and microbial transitions across urbanization, Nature Microbiology (2019).

Walls talk: Microbial biogeography of homes spanning urbanization, Science Advances

Notes
Nov 2019, phys.org

1988, NASA and BC Wolverton.

RL Orwell, RA Wood, MD Burchett, J Tarran, F Torpy.
Water, Air, and Soil Pollution. 177 (1–4): 59–80. 19 September 2006.
doi:10.1007/s11270-006-9092-3.


**Buy Sir Hugh Platt's original 1675 book Garden of Eden, here for $3,500