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In a First, California Moves to Protect People from Toxic PFAS Chemicals in Carpets

By |2018-04-21T13:54:26+00:00April 21st, 2018|Uncategorized|

In a groundbreaking move, California has proposed that carpets and rugs containing the stain-resistant fluorinated chemicals known as PFAS[1] should be considered a priority product under the state’s Safer Consumer Products program. This could lead to the development of safer alternatives to the use of these potentially harmful chemicals in carpets and rugs.

Carpets and rugs cover nearly half of all U.S. homes and workplaces. The California Department of Toxic Substances Control has identified carpets and rugs as the largest potential sources of significant and widespread PFAS exposures, especially for children.

The proposed priority listing is an essential stage in the state’s program to assess toxic chemicals in consumer products and find alternatives. If the listing is made final, it would prompt carpet manufacturers to look for safer alternatives and help shoppers find healthier floor treatment choices for their homes. The public can submit commentssupporting the listing through April 16.

The first stain-resistant carpet was introduced in 1986 with the Stainmaster label. Other manufacturers followed with “Wear-Dated” and “Worry Free” treatments. But these treatments are far from worry free.

To repel stains, the carpet industry used the same kind of chemicals in DuPont’s Teflon cookware – poly- and perfluoroalkyl substances, known as PFAS chemicals. The Scotchgard chemical, called PFOS, and its close chemical cousin PFOA, were phased out under pressure from the Environmental Protection Agency after the revelation of secret studies by their manufacturers that found they caused cancer and birth defects in lab animals, built up in people’s bodies and did not break down in the environment. In studies of tens of thousands of people exposed to PFOS and PFOA, very small doses of the chemicals have been linked to cancer, hormone disruption, immune system harm, reproductive harm and liver damage.

The U.S. carpet industry transitioned away from its use of PFOS, PFOA and other so-called long-chain PFAS chemicals in 2008. But they’ve been replaced by a new generation of “short-chain” chemicals in this class that have many of the same potential health concerns. California regulators lists all PFAS chemicals as having the potential for bioaccumulation; cancer; developmental, endocrine and liver toxicity; and other health hazards. PFASs are found in numerous other consumer items including cookware, clothing, personal care products and cleaning products.

EWG’s 2015 review showed that the majority of PFAS in homes comes from its use on carpets and textiles. The U.S. Centers for Disease Control named carpet as the number one exposure pathway to PFAS for infants and toddlers who spend and lot of time lying, playing and crawling on carpeting. Adults can be exposed from inhalation or ingestion of dust, or dermal contact.

2012 study by University of Alberta researchers documented exceptionally high levels of a short-chain PFAS chemical in the blood of a Canadian family that routinely treated its carpet with 3M’s Scotchgard. The highest levels were observed in the youngest children. High levels of the same short-chain PFASs were detected in household dust and the family room carpet.  Earlier research by Health Canada showed that the amounts of PFAS chemicals in household dust were directly related to the amount of carpeting in homes.

In 2017, the nonprofit Healthy Building Network reported that routine wear and tear, and any type of cleaning, dislodges PFAS chemicals from carpet fibers into air and dust. Amid mounting evidence on the hazards of these chemicals and questions on if we even need these chemicals, momentum is building to eliminate this whole class of chemicalsfrom products.

Spurred by consumer demand and the possibility of regulations, some manufacturers have started exploring alternatives to PFAS chemicals in carpets. They’re finding that carpet can be made easy to care for without toxic chemicals.

But finding information about PFAS-free carpets and rugs can be difficult. Many carpet products are not labeled and there is no comprehensive certification to ensure carpets are free of problematic PFAS chemicals. Some carpets in the U.S. are certified by Green Label Plus, which only tests for a narrow set of volatile organic compounds.

A few companies now sell PFAS-free carpets for commercial installation, but it is not certain when PFAS-free carpet will be available for residential purchases. California’s Safer Consumer Products listing has moved the issue into the spotlight, and it is now up to manufacturers to respond.

EWG recommends:

  • Minimizing the amount of carpet in your living space.
  • Choosing wood or tile floors that can be easily cleaned to remove dust.
  • Looking for natural fiber area rugs made of wool, jute, seagrass or sisal.
  • If carpet is a must, looking for a wool carpet not treated with any additional chemicals.
  • If you choose conventional carpet, telling the retailer you want one without fluorinated chemicals.
  • Vacuuming carpets frequently with a vacuum fitted with a HEPA filter to remove dust.
  • Visiting EWG’s Healthy Living: Home Guide for more tips about choosing better carpet.

[1] PFAS stands for per- and polyfluoroalkyl substances. These chemicals were historically known as PFCs, for per- and polyfluorinated compounds, a term still used sometimes.



Crawling-induced floor dust resuspension affects the microbiota of the infant breathing zone

By |2018-02-04T20:37:06+00:00February 4th, 2018|Uncategorized|



Floor dust is commonly used for microbial determinations in epidemiological studies to estimate early-life indoor microbial exposures. Resuspension of floor dust and its impact on infant microbial exposure is, however, little explored. The aim of our study was to investigate how floor dust resuspension induced by an infant’s crawling motion and an adult walking affects infant inhalation exposure to microbes.


We conducted controlled chamber experiments with a simplified mechanical crawling infant robot and an adult volunteer walking over carpeted flooring. We applied bacterial 16S rRNA gene sequencing and quantitative PCR to monitor the infant breathing zone microbial content and compared that to the adult breathing zone and the carpet dust as the source. During crawling, fungal and bacterial levels were, on average, 8- to 21-fold higher in the infant breathing zone compared to measurements from the adult breathing zone. During walking experiments, the increase in microbial levels in the infant breathing zone was far less pronounced. The correlation in rank orders of microbial levels in the carpet dust and the corresponding infant breathing zone sample varied between different microbial groups but was mostly moderate. The relative abundance of bacterial taxa was characteristically distinct in carpet dust and infant and adult breathing zones during the infant crawling experiments. Bacterial diversity in carpet dust and the infant breathing zone did not correlate significantly.


The microbiota in the infant breathing zone differ in absolute quantitative and compositional terms from that of the adult breathing zone and of floor dust. Crawling induces resuspension of floor dust from carpeted flooring, creating a concentrated and localized cloud of microbial content around the infant. Thus, the microbial exposure of infants following dust resuspension is difficult to predict based on common house dust or bulk air measurements. Improved approaches for the assessment of infant microbial exposure, such as sampling at the infant breathing zone level, are needed.


Infant exposure, Indoor microbial exposure, Particle resuspension, qPCR, 16S rRNA,  gene sequencing

Indoor air quality can’t be ignored — our lives depend on it

By |2018-01-27T16:37:33+00:00January 27th, 2018|Uncategorized|

We often talk about healthy living and quality of life but have you considered the quality of the air you breathe?

Most of us spend up to 90 per cent of our time indoors, according to many surveys. Add up the time you spend at home, in the office and on transport, and you will see how close this figure is for yourself.

The study of indoor air quality did not achieve any public prominence until the 1970s. This was brought on by the “Oil Shock” that rapidly pushed energy prices to unprecedented highs. The response from building managers in the United States and elsewhere was to reduce the fresh air entering a building and recirculate as much as possible to retain heat in winter and keep out heat in summer.

Sick building syndrome

These changes were made with minimal understanding of the effects on indoor air quality. Suddenly a new phenomenon emerged, “sick building syndrome“.

The first indicator was that high levels of carbon dioxide (the most common of the bio-effluents) emitted by the occupants invoked a physiological response that made the air feel “hot and stuffy”.

The second was a build-up of moisture, leading to condensation, particularly where that condensation occurred within wall cavities. This allowed mould to flourish unseen and undetected, until it made its presence felt by outbreaks of eye, nose, throat and skin irritations and eventually the smell from the emitted chemicals.

Volatile organic compounds

Unfortunately, the irritation and smell were generally attributed to chemical exposure and not to biological origins. This led to a four-decade-long obsession with volatile organic compounds (VOCs) and the emission of these chemicals into the indoor air. This was in part understandable because VOCs were also the main focus of environmental protection agencies at that time.

Apart from particularly aggressive chemicals like formaldehyde, emitted from resins in particle board and laminates, and the nitrogen dioxides from gas-fired cookers and heaters, most other VOCs have never been convincingly linked to health effects.

This is hardly surprising when you compare the occupational exposure limits for the same chemicals with their concentration in indoor air. The levels for safe workplace exposure are often 1,000 times higher. So why would we expect any effect in the home or office?

But headlines like “Is your carpet killing you?” are much sexier than “Please remember to open a window occasionally”.

Semi-volatile organic compounds

In the mid-2000s attention switched to semi-volatile organic compounds (SVOCs) as a result of the endocrine disruptor debate. Previously no-one had considered them in indoor air quality because it couldn’t be envisaged how a compound with such a low volatility could be inhaled in any significant quantities.

It has now been shown that dust settling on materials containing SVOCs (vinyl flooring and the like) absorbs the chemicals then is resuspended in the air, for us to inhale or ingest. The Bornehag study linked phthalates (chemicals widely used in plastics) absorbed on particulate matter to asthma.

The most ubiquitous SVOCs are the phthalate plasticisers. Laboratory and environmental studies in animals have provided strong indications that endocrine disruption is taking place. Human evidence is lacking at this stage. But human studies of other effects have shown stronger evidence.

A study in Bulgaria by Scandinavian researchers showed increasing rates of childhood asthma correlated to rising use of phthlates in the home.

Given that most homes did not contain vinyl flooring or seat covering this was at first confusing. But interviews with the households showed a big increase in use of a particular cleaning product that contained phthalate, presumably to rejuvenate vinyl surfaces.

You can open a window, but what if it’s worse outside?

Our traditional way to improve poor indoor air quality is to increase ventilation to purge the contaminants. This works well for volatile organic chemicals and bio-effluents like COand odours, and also works well in suppressing the SVOC-laden dust.

But what do you do when the outside air quality is worse than the inside air? This had long been a problem in inner-city areas before the era of environmental legislation. Later, with the rise of the use of diesel engines for motor vehicles, a new category of pollution has emerged — ultra-fine particle (UFP) pollution. Other sources are bushfire smoke from activities such as land clearing in South East Asia and bushfire mitigation activities in southern Australia and grass pollens, which can result in “thunderstorm asthma“.

In these cases the pollution is coming indoors from outside, as opposed to the traditional indoor air quality problem of pollution being inside and trying to get it out.

While the technology exists to reduce ultra-fine particles coming indoors, it is expensive and not well known.

We should be developing this technology as a required standard for buildings like hospitals, because this is where asthma suffers seek shelter and treatment during such events.

My mantra has always been that I can fix any indoor air quality problem with enough clean, fresh air. This is still true, but that clean air is getting harder to find.



This weird crawling robot baby is used to study dirt and bacteria inhalation

By |2018-01-23T17:06:27+00:00January 23rd, 2018|Uncategorized|

Purdue University researchers built this bizarre crawling robot baby to study how real infants kick up dirt and bacteria from carpet that they then inhale. Engineer Brandon Boor and his colleagues ran the robot over carpet samples removed from people’s homes and then analyzed the particulates that were stirred up. Turns out that the particle concentration is as much as 20 times greater than higher up in the room where we adults breathe. That isn’t necessarily bad though, Boor says.

“Many studies have shown that inhalation exposure to microbes and allergen-carrying particles in that portion of life plays a significant role in both the development of, and protection from, asthma and allergic diseases,” says Boor, an assistant professor of civil engineering and environmental and ecological engineering. “There are studies that have shown that being exposed to a high diversity and concentration of biological materials may reduce the prevalence of asthma and allergies later in life.”

(Purdue University)