Uploaded September 2025 | Updated September 2026, 2 weeks ago
Ever Wonder Why Burnt Popcorn, Cigarette or Foul Bathroom Smells Can Linger for Hours to even Days?
I am sure that we have all experienced the smell of burnt popcorn throughout our home, lingering in the air for many hours to even a day, even though we open all the windows. Ditto for cigarette smoke, or even foul odors from a bathroom, even though fans and ventilation systems are running full blast.
Why the long persistence?
It turns out, that the chemicals causing these smells are absorbed onto surfaces and even within surfaces in far greater quantities than we previously thought possible. For hard, impervious surfaces like metal refrigerator or other appliance doors and windows, a thin film forms on the surfaces from these chemicals, called VOCs (Volatile Organic Compounds), but this is not the main source of the problem. For porous, permeable surfaces like drywall, wooden furniture, concrete surfaces, and even carpets, these chemicals can get trapped within in gaseous form inside the material, or even adhere chemically or physically to the materials.
Then, no matter how much ventilation is provided to the indoor spaces, the smell can linger for many hours to many days as the surface slowly releases the chemicals over time.
This has very important implications for indoor air quality and health.
Please donate to PaulBeckwith.net to support my research and videos connecting the dots on abrupt climate system mayhem.
Please subscribe to my YouTube channel. As well as my website, and YouTube, you can find me on Patreon, Facebook, Twitter/X, LinkedIn, Instagram, Reddit (multiple climate channels within), Quora, TikTok, Discord, Mastodon, Twitch, Vimeo, Bluesky, TruthSocial, Threads, Substack, Tumblr, Pinterest, etc...
Links:
PNAS Peer-Reviewed Scientific Article published today (September 22, 2025):
VOC injection into a house reveals large surface reservoir sizes in an indoor environment
pnas.org/doi/10.1073/pnas.2503399122
Significance
Organic contaminants partition to indoor surfaces, giving rise to human exposure via dermal uptake and nondietary ingestion pathways. However, the total partitioning capacity of indoor surfaces has not been experimentally quantified in the built environment. By injecting various organic contaminants into the air of a test house, we determine the degree to which these contaminants partition to indoor surfaces. Our estimates of the total surface partitioning capacity are much larger than if the reservoirs are taken to be thin organic films on smooth, impermeable surfaces. This directly affects assessments of how humans are exposed to contaminants that undergo partitioning between indoor air and surfaces.
Abstract
The total partitioning capacity of indoor surface reservoirs determines the mechanism by which humans receive nondietary exposure to organic contaminants, via inhalation, dermal uptake, and dust ingestion. And yet, this capacity is largely unknown. Surface organic films are ubiquitously present but have very low partitioning volume being only 10’s of nanometer thick, whereas other surface reservoirs such as building materials and furnishings can be permeable or porous with large surface areas at the molecular level. Here, we assess the total partitioning capacity of volatile organic compounds (VOCs) in an indoor environment from the measured kinetics of VOC surface uptake after injection of compounds with variable volatility into a well-characterized, unoccupied test house. We show that the size of the indoor surface reservoirs is very large with an octanol-equivalent average thickness on the order of micrometers, indicating that permeable/porous materials such as painted surfaces and wood are likely the major surface reservoirs in the house rather than organic surface films. Large surface reservoirs result in compounds with octanol-air partition coefficients (KOA) larger than 105 being predominantly partitioned to indoor surface reservoirs, making them hard to be removed via ventilation. This result significantly impacts our understanding of VOC fate and human exposure in indoor environments. With such a large partitioning capacity, organic contaminants will have much longer indoor residence times than previously predicted.
Link to paper figures:
pnas.org/doi/10.1073/pnas.2503399122
Please donate to PaulBeckwith.net to support my research and videos connecting the dots on abrupt climate system mayhem.
Please subscribe to my YouTube channel. As well as my website, and YouTube, you can find me on Patreon, Facebook, Twitter/X, LinkedIn, Instagram, Reddit (multiple climate channels within), Quora, TikTok, Discord, Mastodon, Twitch, Vimeo, Bluesky, TruthSocial, Threads, Substack, Tumblr, Pinterest, etc...
Ever Wonder Why Burnt Popcorn, Cigarette or Foul Bathroom Smells Can Linger for Hours to even Days?
I am sure that we have all experienced the smell of burnt popcorn throughout our home, lingering in the air for many hours to even a day, even though we open all the windows. Ditto for cigarette smoke, or even foul odors from a bathroom, even though fans and ventilation systems are running full blast.
Why the long persistence?
It turns out, that the chemicals causing these smells are absorbed onto surfaces and even within surfaces in far greater quantities than we previously thought possible. For hard, impervious surfaces like metal refrigerator or other appliance doors and windows, a thin film forms on the surfaces from these chemicals, called VOCs (Volatile Organic Compounds), but this is not the main source of the problem. For porous, permeable surfaces like drywall, wooden furniture, concrete surfaces, and even carpets, these chemicals can get trapped within in gaseous form inside the material, or even adhere chemically or physically to the materials.
Then, no matter how much ventilation is provided to the indoor spaces, the smell can linger for many hours to many days as the surface slowly releases the chemicals over time.
This has very important implications for indoor air quality and health.
Please donate to PaulBeckwith.net to support my research and videos connecting the dots on abrupt climate system mayhem.
Please subscribe to my YouTube channel. As well as my website, and YouTube, you can find me on Patreon, Facebook, Twitter/X, LinkedIn, Instagram, Reddit (multiple climate channels within), Quora, TikTok, Discord, Mastodon, Twitch, Vimeo, Bluesky, TruthSocial, Threads, Substack, Tumblr, Pinterest, etc...
Links:
PNAS Peer-Reviewed Scientific Article published today (September 22, 2025):
VOC injection into a house reveals large surface reservoir sizes in an indoor environment
pnas.org/doi/10.1073/pnas.2503399122
Significance
Organic contaminants partition to indoor surfaces, giving rise to human exposure via dermal uptake and nondietary ingestion pathways. However, the total partitioning capacity of indoor surfaces has not been experimentally quantified in the built environment. By injecting various organic contaminants into the air of a test house, we determine the degree to which these contaminants partition to indoor surfaces. Our estimates of the total surface partitioning capacity are much larger than if the reservoirs are taken to be thin organic films on smooth, impermeable surfaces. This directly affects assessments of how humans are exposed to contaminants that undergo partitioning between indoor air and surfaces.
Abstract
The total partitioning capacity of indoor surface reservoirs determines the mechanism by which humans receive nondietary exposure to organic contaminants, via inhalation, dermal uptake, and dust ingestion. And yet, this capacity is largely unknown. Surface organic films are ubiquitously present but have very low partitioning volume being only 10’s of nanometer thick, whereas other surface reservoirs such as building materials and furnishings can be permeable or porous with large surface areas at the molecular level. Here, we assess the total partitioning capacity of volatile organic compounds (VOCs) in an indoor environment from the measured kinetics of VOC surface uptake after injection of compounds with variable volatility into a well-characterized, unoccupied test house. We show that the size of the indoor surface reservoirs is very large with an octanol-equivalent average thickness on the order of micrometers, indicating that permeable/porous materials such as painted surfaces and wood are likely the major surface reservoirs in the house rather than organic surface films. Large surface reservoirs result in compounds with octanol-air partition coefficients (KOA) larger than 105 being predominantly partitioned to indoor surface reservoirs, making them hard to be removed via ventilation. This result significantly impacts our understanding of VOC fate and human exposure in indoor environments. With such a large partitioning capacity, organic contaminants will have much longer indoor residence times than previously predicted.
Link to paper figures:
pnas.org/doi/10.1073/pnas.2503399122
Please donate to PaulBeckwith.net to support my research and videos connecting the dots on abrupt climate system mayhem.
Please subscribe to my YouTube channel. As well as my website, and YouTube, you can find me on Patreon, Facebook, Twitter/X, LinkedIn, Instagram, Reddit (multiple climate channels within), Quora, TikTok, Discord, Mastodon, Twitch, Vimeo, Bluesky, TruthSocial, Threads, Substack, Tumblr, Pinterest, etc...
