Contaminated soil beneath a dwelling can send toxic fumes through flooring and affect the health of residents. At the same time, furniture, paint, building materials and other household items also release compounds that can negatively impact indoor air quality.
A new tracking tool developed at the University of Copenhagen can reveal the source of harmful compounds in indoor environments much more accurately than in the past. Environmental threats from the past such as toxic chemicals from industry and oil tanks can lurk in soil beneath dwellings, seep up through flooring and impact the indoor air quality and health of residents.
Unfortunately, these toxic compounds can be difficult to detect as the things that we surround ourselves with at home, including cleaning products, furniture and building materials, also release chemical compounds into the air, which can be harmful, while hiding far more serious contamination beneath our homes.
Now, a group of researchers from the University of Copenhagen's Department of Plant and Environmental Sciences, together with Eurofins, a global analytical testing laboratory, has developed a novel tracking method. A chemical fingerprint, taken by way of an air sample from a dwelling, can distinguish between chemical compounds and detect harmful pollutants from both the ground below and from air within a home.
"The chemical fingerprint that we've developed is capable of detecting up to one thousand different compounds in indoor air. You can distinguish compounds that originate from pollution beneath a home, such as an oil tank, from those which originate from indoor sources, such as paint or new furniture," explains Professor Jan H. Christensen of the Department of Plant and Environmental Sciences.
The method works by collecting air samples from both within and beneath a dwelling. Thereafter, compounds from the samples are separated in a laboratory by heating the air and converting the compounds into gas, which is then measured and analysed. At the same time, a mathematical model accounts for sample uncertainties.
"The mathematical model we've developed is what defines this method. It reduces the uncertainty of the chemical fingerprints and accounts for changes that occur as air passes from the soil beneath a building, up through its foundation and into the indoor environment. Compared with previous models, this one allows us to discern with far greater precision the degree to which indoor pollution originates from contamination beneath a dwelling versus how much comes from pollutants within the indoor environment," explains Jan H. Christensen.
Serving the Capital Region
The Capital Region of Denmark has systematically investigated and cleaned up contaminated sites that pose a risk to human health or the environment for years. Particular attention is paid to former industries such as metal degreasing and dry cleaning, which often spawned pollution by way of chlorinated solvents. Likewise, old petrochemical spills can impact indoor air quality. In these cases, it is the regional authority's task to avert risk in dwellings.
The Capital Region of Denmark looks forward to deploying the tool as it can rapidly determine a pollution source and allow them to focus on cases where soil pollution is impacting indoor air quality.
"The new approach allows us to identify serious cases more quickly. That is, cases where indoor air problems stem from soil contamination and are not due, for example, to recently purchased furniture, which can also affect indoor air quality. As such, we expect to be able to save both time and money on investigating cases that have traditionally been very complicated to settle," states Chief Consultant Henriette Kern-Jespersen, a civil engineer who works with soil and groundwater decontamination at the Capital Region of Denmark.
From now through Christmas, the Capital Region will test and evaluate the tracking tool, known as Chem Fing Air-a chemical fingerprint of the air. Beyond that, Henriette Kern-Jespersen expects for the tool to be used in the Capital Region, and hopefully, in other Danish regions as well.
80-90 percent of our time is spent indoors
Indoor air quality is no joke. On average, Danes spend 80-90 percent of their time indoors, where we are exposed to more than 900 different chemicals, particles and microorganisms circulating in the air.
"Excessive levels of chemical compounds can easily occur in our indoor environments and some of them will be harmful to our health. Most of us know that strange smells arise if we haven't aired things out for many days. Among other things, this is the smell of various chemical compounds becoming concentrated," says Jan H. Christensen.
In addition to underground pollution, the chemical fingerprint can detect elevated levels of chemical compounds from sources within the home.
"We know that a number of everyday household items release petrochemical compounds, among others, that can pose a risk to our health. However, they have a complex chemical fingerprint, which was difficult to detect in the past, when they are mixed with other indoor environmental factors. But now we can. This will make it easier for us to determine whether certain household compounds are harmful to our health," says Jan H. Christensen.
Facts about the sources of poor indoor air quality:
The Danish Environmental Protection Agency lists eight key sources of poor indoor air quality:
- Consumer products, such as consumer electronics, toys, cleaning products and furniture
- Compounds emitted from residents and pets
- Compounds from building materials
- Chemical reactions between individual compounds in the home
- Soil pollution
- Outdoor air pollution
- Cooking, Smoking and cleaning in the dwelling, etc.
- Indoor moisture
Facts about Chem Fing Air:
- The Chem Fing Air chemical fingerprinting system has been developed in collaboration with the Capital Region of Denmark and Eurofins laboratory.
- The method consists of a combination of chemical fingerprint analyses of indoor air and air from soil contamination beneath a dwelling, as well as a mathematical modelling of the fingerprints to determine the contribution from soil pollution versus pollution arising from indoor sources.
- The researchers developed software that imports chemical fingerprints and thereafter performs a range of data processing operations.
- For example, minor changes in the intensity of measurements and changes as air passes through the floor of a dwelling are corrected for, so that a direct comparison of the chemical fingerprints in air from beneath a dwelling and fingerprints from its indoor environment can be made.