A science presenter, writer, speaker & former TV host; author of The Skeptic's Handbook (over 200,000 copies distributed & available in 15 languages).



Australian Speakers Agency


The nerds have the numbers on precious metals investments on the ASX

The Skeptics Handbook

Think it has been debunked? See here.

The Skeptics Handbook II

Climate Money Paper


Air conditioning reduces indoor air pollution — give me cheap electrons

Just another way cheaper electricity saves lives.

Air conditioners,

Photo by Photo by noodle kimm on Unsplash

It turns out hotter rooms have higher indoor pollution. Levels of formaldehyde are lower in the morning and rise with the temperature. Air conditioning in hot summers, keeps the temperature down and will reduce the amount of formaldehyde and other pollutants from out-gassing from furniture and gypsum walls.  Obviously those who can’t afford to run the air conditioner and who live in warmer rooms in summer will be exposed to more pollution.

Though the worst situation was in 1970s homes with radiant heaters installed on gypsum sheets. In that case, people who can’t afford to heat may avoid some fumes.

Opening windows will clear out the indoor pollution, but houses are increasingly being designed to stop draughts to be more energy efficient.

The message: get rich or open windows when it’s nice outside, move those bar heaters off the walls, and buy peace lilies, bamboo palms, and dracaenas.

Researchers uncover indoor pollution hazards

By Tina Hilding, Voiland College of Engineering and Architecture

PULLMAN, Wash – When most people think about air pollution, they think of summertime haze, traffic or smokestack exhaust, wintertime inversions, or wildfire smoke. They rarely think of the air that they breathe inside their own homes.

In a new study of indoor air quality, a team of WSU researchers has found surprisingly high levels of pollutants, including formaldehyde and possibly mercury, in carefully monitored homes, and that these pollutants vary through the day and increase as temperatures rise. Their study, led by Tom Jobson, professor in the Department of Civil and Environmental Engineering, and graduate student Yibo Huangfu, was published in the journal, Building and Environment.

Researchers know that air pollution, whether inside or outside, has a significant impact on people’s health, including their heart, lungs, brain, and neurological health. But, while the government has increased regulation of outdoor air pollution over the past 40 years, there is little regulation of the air in people’s homes. Building laws generally require that homes are structurally sound and that people are comfortable — with minimal impacts from odors and humidity.

“People think of air pollution as an outdoor problem, but they fail to recognize that they’re exposing themselves to much higher emission rates inside their homes,” Jobson said.

These emissions come from a variety of sources, such as building materials, furniture, household chemical products, and from people’s activities like cooking.

One of the ways to clear out harmful chemicals is with ventilation to the outdoors. But, with increased concern about climate change and interest in reducing energy use, builders are trying to make homes more airtight, which may inadvertently be worsening the problem.

The researchers measured both indoor and outdoor air at the home, finding that indoor air concentrations of many pollutants are much larger, by a factor of 100 for some chemicals.


Air conditioners, Photo by Alexandre Lecocq on Unsplash


 In their study, the researchers looked at a variety of homes – meant to reflect the typical housing styles and age in the U.S. They found that formaldehyde levels rose in homes as temperatures increased inside – between three and five parts per billion every time the temperature increased one degree Celsius.

“As a home gets hotter, there is a lot more formaldehyde in the home. The materials are hotter and they off-gas at higher rates,” Jobson said.

The work shows how heat waves and changing regional climate might affect indoor air quality in the future.

“As people ride out a hot summer without air conditioning, they’re going to be exposed to much higher concentrations of pollutants inside,” he said.

The researchers also found that pollution levels varied throughout the day – they were highest in the afternoon and lowest in the early morning. Until now, manufacturers and builders have assumed that pollutants stay the same throughout the day as they consider the emissions from their materials, so they may not be getting a true picture of how much pollution people are exposed to indoors, he said.

The researchers also were surprised to find in one home that gypsum wallboard emitted high levels of formaldehyde and possibly mercury when it’s heated. That home, built in the early 1970s, had radiant heating in its ceiling, which was a popular heating system at that time. After finding high levels of formaldehyde in the home, the researchers suspected the gypsum wallboard radiant ceiling in the home. About half of the gypsum used in homes as drywall is made from waste products of the coal industry. They pulled a piece from the home, heated it up in their laboratory, and measured high levels of formaldehyde – as much as 159 parts per billion. Household formaldehyde exposure is not regulated in the United States, but the US Agency for Toxic Substances and Disease Registry, part of the Centers for Disease Control, has set eight parts per billion as posing a minimum risk level.

“Exposure to these chemicals impacts people’s ability to think and learn,” said Jobson. “It’s important for people to be more cognizant of the risk — Opening a window is a good thing.”

The researchers plan to continue looking at ways to reduce exposure to indoor air pollutants, such as using green building materials.

“We have to balance making more energy efficient homes with protecting our health and cognitive function,” he said.

The work was funded by the U.S. Environmental Protection Agency.

Photo by Alexandre Lecocq on Unsplash

VN:F [1.9.22_1171]
Rating: 9.9/10 (35 votes cast)
Air conditioning reduces indoor air pollution -- give me cheap electrons , 9.9 out of 10 based on 35 ratings

Tiny Url for this post:

29 comments to Air conditioning reduces indoor air pollution — give me cheap electrons

  • #
    el gordo

    Indoor pollution is insidious in the third world, millions die prematurely every year.

    In the first world Greta Thuneberg can see carbon dioxide in the air?


  • #
    Sceptical Sam

    Researchers know that air pollution, whether inside or outside, has a significant impact on people’s health, including their heart, lungs, brain, and neurological health.

    Yes. All very good.

    However, what I’d like to know is the extent to which all these adverse impacts of air pollution on health has constrained the ever increasing life expectancy of western society.


    • #

      ‘Exposure to indoor air pollution may be responsible for nearly 2 million excess deaths’
      Problem is with these or any studies, is that to sample correctly you would have to have ONLY indoor pollution and exclude population exposed to all the other pollutions including food pollution. Even then you cant know exactly what the sample is really exposed to in the lifetime. Nearly impossible. I read these studies with a certain degree of skepticism.


  • #

    I’ve been posting stuff on Jo’s previous thread – didn’t notice the new one. never mind:

    6 Jun: ClimateNewsNetwork: Arctic sea ice loss affects the jet stream
    by Tim Radford
    (Tim Radford, a founding editor of Climate News Network, worked for The Guardian for 32 years, for most of that time as science editor. He has been covering climate change since 1988)
    The jet stream affects northern hemisphere climates. And global warming affects the behaviour of the jet stream. Prepare for yet more extremes of seasonal weather.
    LONDON, 6 June, 2019 − Did you shiver in a winter ice storm? Could you wilt in a protracted heatwave this summer? German scientists have just identified the guilty agency and delivered the evidence implicating the jet stream.
    Blame it on Arctic warming, they conclude: the retreat of the sea ice over the polar ocean has distorted the pattern of flow of the stratospheric winds usually known as the jet stream.

    It is not a new idea. But this time, scientists have employed artificial intelligence and a machine-learning programme to accurately model the changes in the jet stream and then link these to changes in the chemistry of the upper atmosphere, and increasing patterns of twisting waves in the high altitude winds which then distort seasonal weather in the northern hemisphere mid-latitudes. They describe their research in the journal Scientific Reports (LINK)…

    Professor Rex: “This holds tremendous potential for future climate models, which we believe will deliver more reliable climate projections and therefore a more robust basis for political decision-making.”


    • #
      el gordo

      The Southern Hemisphere is ignored, so Its all bunk.

      A wayward jet stream in both hemispheres, caused by a cool sun, creates blocking highs which force the jet stream to meander.

      My hypothesis needs critiquing.


  • #
    Another Ian

    ““As people ride out a hot summer without air conditioning, they’re going to be exposed to much higher concentrations of pollutants inside,” he said.”

    Added to the detrimental effects of CAGW in 3, 2, 1- – ?


  • #
    Tarquin Wombat-Carruthers

    And the Shorten/Bowen franking credit confiscation would mean the difference between my use of air conditioning and its avoidance!


    • #
      Bill in Oz

      E G that’s an interesting hypothesis.
      But it needs more explanation and evidence to support it.Tq, I get no franking credit
      But avoid air conditioning as much as possible
      It’s too damned expensive.


      • #

        But avoid air conditioning as much as possible
        It’s too damned expensive.

        For the past five years, in Geelong, Victoria, I’ve had no need for air-conditioning. However, in winter the gas heater gets a real workout. So much for global warming.


  • #

    Presumably air conditioners in cars would have a similar effect. With fossil fuel driven cars there is less consideration with running out of fuel than with EVs. With EVs, if the battery is running low, the occupants may be more tempted to drive without the aircon.


  • #

    Presumably the outgassing would be most severe in a new house and level off after a few years?

    They say new cars have very high levels of VOCs (volatile organic compounds) but the levels drop quickly.


  • #
    Ian Hill

    Growing up in a trust home in country SA in the 1960s the second biggest pollutant was smoke from wood fires in the kitchen, lounge room, bathroom and laundry. The biggest was my dad’s cigarette smoke. Dad was a carpenter and worked with asbestos and that would have been on his overalls. Of course the smoking continued during long car trips to Adelaide, with all seven of us in the station wagon. Mum didn’t smoke. Somehow we all made it. All my brothers and sisters are still healthy. Maybe we were lucky. We couldn’t afford to have luxuries like gypsum panelling, carpet and TV. Probably not much formaldehyde around but there were fumes from the kerosene heater in the kitchen. It was common to have some mercury to play with, brought home from school science lessons. Today’s teachers would be horrified at what was normal practice then. The only world-ending scare was the possibility of nuclear war and in 1962 it could have happened. I saw how worried my parents and in fact all adults were. Somehow the teachers were stoic about it. The only education I can recall about climate was why seasons occur.


    • #
      Bill in Oz

      I grew up in Victoria in outer suburbs of Melbourne
      And yes you named all the hazards.
      Ciggarete smoke in the car was a pain.


  • #

    6 Jun: YaleClimateConnections: Rising demand for air conditioning could make climate change even worse
    By Sarah Wesseler
    But a new $1 million prize could boost climate-friendly AC technology.
    Between 1992 and 2016, more than 22,000 people in India died as a result of heat exposure. In 2015 alone, the death toll reached 2,300.
    Authoritative projections indicate that under a high-emissions scenario, 75 percent of the country’s population will face dangerous levels of heat and humidity by 2100. Cities that now house millions would become uninhabitable.
    One reason that India’s heat waves are particularly deadly is the scarcity of air conditioning. The nation has one of the lowest penetrations of AC technology in the world – today, fewer than 10 percent of all its households have it…

    The cold crunch
    The rise of air conditioning in India plays a major role in what the International Energy Agency, in its “Future of Cooling” (LINK) report, calls the “cold crunch” – a phenomenon it describes as one of the most critical energy issues of our time. This “crunch” refers to a projected dramatic rise in the use of AC – most of it residential – in emerging economies. India is expected to lead the pack in terms of numbers of room units coming online, but Indonesia, Brazil, and other nations will also experience significant growth…

    In India, new air conditioning units could result in a 1,500 percent increase in energy demand by 2050, according to the IEA report…

    To jumpstart innovation, the Global Cooling Prize is offering money for the development of an affordable room AC unit that has five times less climate impact than current models…READ ON


  • #

    5 Jun: Science 2.0: Climate Change Will NOT End Human Civilization By 2050, ‘Overblown Rhetoric And Unsupportable Doomist Framing’ Says Michael Mann
    By Robert Walker
    This is scaring so many people and is running in so many online news outlets, but has no scientific credibility. It’s written by a couple of businessmen, with a foreword by a retired admiral, and no scientific peer review. I was glad to see that at least some of the ***most highly regarded news sites didn’t run this, such as the NY Times, Washington Post, The Times, The Guardian, BBC News, Nature, or the Smithsonian magazine. I was very disappointed to see CNN, the Independent and several others running it without explaining its dubious credentials,

    As an example, Spratt and Dunlop, the two Australian businessmen, say that in their worst case scenario, by 2050…ETC

    Michael Mann, respected climate scientist at Pennsylvannia State University, calls their report “overblown rhetoric, exaggeration, and unsupportable doomist framing”…ETC


    • #
      Sceptical Sam

      Sounds like Michael Mann, the doomsayer king, doesn’t like being “out-doomed’ by a couple of antipodean spivs.


  • #

    5 Jun: New Statesman: Should we be practising “climate change optimism”?
    Looking at our climate crisis with pessimism is neither constructive nor fully deserved.
    by Sophie McBain
    Transitioning to a more sustainable economy will require short-term sacrifices, especially among the global rich. We’ll need to consume less and reuse more, and cut down on luxuries such as meat, plane travel and air conditioning. We may face higher carbon taxes. When people are polled about how much they’d be willing to spend to avert climate emergency, the results are rarely promising. A majority of American respondents recently told the Associated Press that they would support a carbon tax to restore forests or support renewable energy research, but 70 per cent would balk at paying a $10 monthly fee and 40 per cent objected to a $1 a month tax…

    keep this up virtue-signalling, and soon I’ll be giving up on watching sport entirely:

    6 Jun: AustralasianLeisure: Tennis Australia commits to United Nations climate change action
    Tennis Australia has become the first Australian sporting organisation to commit to the United Nations Sports for Climate Change Action Framework.
    Speaking at an event for climate action in Paris, attended by the United Nations Framework Convention on Climate Change (UNFCCC) Executive Secretary Patricia Espinosa, Tennis Australia Chief Executive and Australian Open Tournament Director Craig Tiley explained how sport can play a major role in promoting innovative and sustainable practices required to achieve climate neutrality.

    Energy and atmosphere
    • NTC has naturally ventilated indoor tennis courts that keep players cool, even when outdoor temperatures are high; this also reduces the reliance on air conditioning equipment
    • Mechanical heating, cooling and ventilation systems have also been upgraded in RLA – enabling the system to be scaled in intensity depending on the occupation levels – reduces the electricity usage of both fans and cooling plant.
    • Solar arrays positioned on the roof of the National Tennis Centre and Tennis HQ to provide renewable energy for use in those buildings.
    • AO 2018 achieved 13.5% reduction in electricity use across the three arenas a result of mechanical plant optimisation initiatives…READ ON


  • #

    Will the various “”"governments”"” of the world also provide us with continuous formaldehyde monitors (to keep our smart meters company)?


  • #
    Scott Henderson

    Fascinating. I work in building commissioning & IAQ is one thing we consider. To knock these pollutants down in new buildings, we flush them with air – typically a 2 week pricess. First time i have seen indoor air pollution evaluated in existing buildings.

    Go Cougs! (I am a proud alum of WSU)


  • #


    Nobody seems to have measured the indoor CO2 levels. Why not?


  • #

    Of course all these air con pollutant removers can be run of un-renewables cant they?


  • #
    Roy Hogue

    A few years back it was radon. Radon was going to kill me if I didn’t put in expensive ventilating systems. Guess what? I didn’t and nobody talks about it anymore and I’m still here. What will kill me next if I don’t do something someone else says I must do? I already lived through global warming. Now my house is out-gassing. Let’s find out first whether the researchers are right or whether they’re just out-gassing.


  • #

    And compared with the amount of formeldhyde produced by gum trees in native forests this proves we must avoid bush walks!


  • #

    I have read about the issue of indoor air pollution in tightly-sealed and insulated homes several times now. While not possible in many areas, there seems to me to be an absurdly easy solution for some places.

    I live in a Southern U.S. state. We can have cold snaps in the winter, with highs not getting much above 0 C. We can also have heatwaves in the summer, with lows around 27 C and highs of 37 C. But in both instances, such extremes last for mere days. Temps will moderate, and, at some point, be between 17 C to 24 C, if only for an hour.

    It seems to me that if a well-insulated house went through a whole-house indoor-outdoor air exchange once a day when temps were in the 17-24 degree range, it would solve any issues with indoor air pollution while minimizing energy usage for heating and AC. Oddly, though, I do not see any company advertising such a system.