Effect Measure

Lung damage from air fresheners?

The “fresh air” smell of a lot of air fresheners is really the smell of pollution according to a paper from scientists at the National Institute of Environmental Health Sciences. That’s because 1,4 dichlorobenzene (1,4 DCB), found in air fresheners, toilet bowl cleaners, mothballs and various “deodorizing” products, also causes modest decreases in lung function.

“Even a small reduction in lung function may indicate some harm to the lungs,” said NIEHS researcher Stephanie London, M.D., lead investigator on the study. “The best way to protect yourself, especially children who may have asthma or other respiratory illnesses, is to reduce the use of products and materials that contain these compounds.”

The researchers examined the relationship between blood concentrations of 11 common volatile organic compounds and lung function measures in a representative sample of 953 adults. VOCs are a diverse set of compounds emitted as gases from thousands of commonly used products, including tobacco smoke, pesticides, paints, and cleaning products. VOCs are also released through automotive exhaust. The researchers found that of the common VOCs analyzed, which included benzene, styrene, toluene, and acetone, only the compound 1,4 DCB was associated with reduced pulmonary function and this effect was seen even after careful adjustment for smoking, The researchers found that 96 percent of the population samples had detectable 1,4 DCB blood concentration levels. African Americans had the highest exposure levels and non-Hispanic whites the lowest. (via Science Blog)

This is another example of indoor air pollution from a consumer product. The reductions in the particular measure of pulmonary function, Forced Expiratory Volume in 1 second, compared those with the highest body burdens of 1, 4 DCB and those with the lowest. The differences were fairly small, about 4%. Concurrent risks that might have confounded the association were accounted for, including type of heating, use of wood fires, age of house, presence of furred pets, occupation, socioeconomic status, environmental tobacco smoke, smoking history, and diagnosis of asthma or emphysema.

FEV1 is an indicator of relative airway obstruction. One might ask if a 4% decrease, even if statistically significant is of public health significance. The answer is yes, for two reasons. The first is the one indicated by London. It is an indication there is damage to the lungs.

The other is more subtle. Pulmonary function tests give measurements of lung function that are vary in the population in a continuous distribution. Everyone has a substantial reserve in pulmonary capacity and we don’t see clinical symptoms until a substantial amount of pulmonary function has eroded. At some point we move from someone without symptoms to someone who begins to have clinical effects. If you imagine a big bell curve of FEV1 measures, at some point in the lower tail of that curve where some people begin to get short of breath. Many things will determine your position on the curve, not just whether you have air fresheners in your home. But if you take the whole curve and you move it to the left by a 4% decrement in FEV1, you start to push some over the line separating asymptomatic and symptomatic. Because the area in the tail of the distribution is fairly small compared to the area under the rest of the curve, a small leftward shift can cause a substantial increase in the percentage of people with clinically evident obstructive pulmonary disease.

If this worries you, that’s appropriate but don’t panic. Stop, collect yourself and take a deep breath. Oops!


  1. #1 G in INdiana
    August 21, 2006

    I stopped using all products that contain this stuff ages ago. I rely on the old fashioned cleaners like vinegar, water, elbow grease, and use citrus based air fresheners (or matches like the old folks did back in the day.)
    My daughter has a type of asthma that is triggered when she gets a cold or flu. Once I stoppped using those commercial cleaning products, her incidence of colds decreased and so did her asthma attacks.
    My dad was a big air freshener user and when he died in February, the lung infection had made Swiss cheese out of his lungs. He had been a smoker years before but never stopped with the bloody air fresheners. I wonder now if those things contributed to his inability to recover from the lung infection that eventually killed him.

  2. #2 Ground Zero Homeboy
    August 22, 2006

    Does this include those stupid christmas tree things that stoners hang from their rear-view mirrors?

  3. #3 Ana
    August 22, 2006

    Firmenich, one of the biggest companies that creates, produces and sells aromas, flavors, fragrances – ‘smells’ is hugely successful. It has been demonstrated, again and again, that people will buy a product that has an attractive smell and will prefer it to one that has no smell.

    Humans’ smelling capacities are poor compared to dogs’ for example, but odor locks into some atavistic part of the brain, it is said, and humans react to it unconsciously, helplessly. A chemical simulacrum, 20 times in strength of the original smell (fresh ocean breeze that has blown over fruit orchard) and molecularly quite different, will hook em, every time. The only way to put a stop to it is legal banning.

    By now, people’s experience with smell has been altered by these companies and the those that use their products. People associate the ‘fresh’ smells with cleanliness, propriety, richness, social status. ‘Natural’ smells such as human sweat, wood rotting in a forest, ripe cheese, are considered utterly disgusting. (Some elderly gourmets in my part of the world are tolerant of the last.)

    I did an informal test at home. It was fun. I used past-shelf date yoghourt, meat, and vege, and hid visual cues. Not a single one of my subjects (all teens) could discern which food was safe to eat. As I was the one who decided that, all of it has no value, but the comments were very interesting. They complained, making them smell things was weird; the dates were written on the goods, what was it about? Etc.

    Firmenich: http://tinyurl.com/k6edu

    Btw, in my little pond, odor is the number one reason why high school students will not longer participate in the dissection of rats.

  4. #4 AF
    August 22, 2006

    Does this go for candles too?

  5. #5 kim
    August 22, 2006

    I despise those little plug-in air fresheners. Most of them are oil-based. Use them long enough and you get a thin sheen of oil all over everything in your house; how disgusting is that. The lung issues just seal the deal for me.

  6. #6 caia
    August 22, 2006

    Ana I’ve heard that people in less scent-saturated cultures (e.g., living in the rainforest) have much better senses of smell than those of us living in industrialized and heavily-scented places.

    I find my sense of smell is much improved since I stopped using heavy scents, and I’m not fragrance free by any means. But I don’t like the scent of scented detergent now anything but unscented smells not clean to me. I sometimes have to change seats in a theatre not to sit next to the lady who has doused on the parfume… and if I can smell you coming, I don’t think, “is that Chanel #5?”, I think, “what kind of stank are you covering up with that?” (Sometimes it’s clearly cigarette stank, and I still smell that first, so smokers… it’s not working.)

    I’ve heard that commerical fragrances aren’t well tested, and can contain trace amounts of benzene… is that true?

  7. #7 rsm
    August 23, 2006

    Yes, fragrances contain benzene and a large number of other chemicals, almost all of which have never been tested for safety, and a number of which are known to cause health detriment and morbidity.

    When the FEV gets low enough, you have asthma.

    A lesser-known but more common problem caused by fragrances is sinus distress, known as vaso-motor rhinitis. Many, and perhaps most of those who believe they suffer from allergies are also, or solely, responding to chemicals in the air, of which fragrances are the most common.

    30% of migraine sufferers recognize fragrances as triggers.

    Skin doctors have begun to counsel patients with rashes to avoid laundry fragrances and to laundry with unscented detergents, and to use no scented fabric softeners or dryer sheets. The effect is often dramatic in clearing up the urticaria.

  8. #8 Ground Zero Homeboy
    August 24, 2006

    I highly recommend the book “The Emperor of Scent”. Even the first page excerpted is a delight.


    I really must read it someday.

  9. #9 Rachel Richman
    November 19, 2007

    The problem of exposure to a volatile organic compound (VOC), called 1,4 dichlorobenzene (1,4 DCB) may possibly cause a decline in lung function being a big problem in the future more than it is now. The only way we can help people not be effected by this, is to educate the future generations. Research conducted by the NIH states that a chemical compound found in many air fresheners, toilet bowl cleaners, mothballs and other deodorizing products, may be harmful to the lungs.
    The most popular item carrying these chemicals I believe are air fresheners in cars and homes. A study released in May, 2006 by the California Air Resources Board, warned that several composites found in air fresheners and household cleansers can reach unsafe concentrations inside homes, with paradichlorobenzene from slow-dissolving air fresheners and toilet-bowl refresheners posing a problem because it releases a chemical (dichlorobenzene or 1,4-DCB) into the air over a period of time. �The best way to protect yourself, especially children who may have asthma or other respiratory illnesses, is to reduce the use of products and materials that contain these compounds.� This was said by NIEHS researcher Stephanie London, M.D. I agree with this quote, we need to protect especially children and people with respiratory dieseases. If you are also a smoker, the chances are that your lungs are more susceptible to lung damage.


    (2006 1 September). Breath Matters . Retrieved November 19, 2007, Web site: http://www.californialung.org/ALAC/enews0608.html

    Elliott L, Longnecker MP, Kissling GE, and London SJ. Volatile Organic Compounds and Pulmonary Function in the Third National Health and Nutrition Examination Survey, 1988-1994. Environmental Health Perspectives. Volume 114, Number 8, August 2006. View Article Abstract http://ehp.niehs.nih.gov/docs/2006/9019/abstract.html.

  10. #10 Judith
    December 19, 2010

    I’m getting worried about the air freshener issue. Lately, when my husband and I take neighborhood walks, we inevitably run into areas in front of homes polluted with either air freshener or laundry perfume smells. These are really strong heavy smells, almost enough to taste, if you know what I mean.

    I can only wonder whether the people inside these homes can still smell anything at all, and what such a large concentration of this oil-based material is doing to their lungs.

  11. #11 Kim Prybuto
    June 23, 2011

    Can anyone give me input into the growing fad of teens and young adults actually smoking air freshener (the kind in crystal form)to get high. They say it is similar to a pot high. The word needs to get out how dangerous this is…especially when it is harmful to our lungs to just have it in our home.

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