Tag: pollution

When indoor air is more polluted than outdoor air

“Besides the contaminants we find outside, we also have indoor contaminants. There are pollutants typical of homes such as dust, spores, moulds, and those produced by human activities like cooking and house-cleaning, that contribute to the release of additional damaging substances,” expert warns

Indoor air pollution kills 4.3 million people globally every year, according to the World Health Organization (WHO). The main causes are heating and cooking practices that produce high levels of toxic substances, such as fine particles and carbon monoxide.

Prof. Alessandro Miani
Prof. Alessandro Miani

Doctor Alessandro Miani, heads-up the non-profit Italian Society for Environmental Medicine (SIMA), which recently drew up a set of rules to preserve the air we breathe in our homes and offices. Miani, who is also professor of hygiene and environmental prevention at the University of Milan, discusses environmental medicine and the need for public health strategies to tackle indoor air pollution.

Professor Miani, the last WHO report shows that indoor air may be more harmful to health than outdoor air. Can you explain how this happens?
Indoor air is basically the same as outdoor air, but the difference lies in the amounts and types of contaminants. Indeed, besides the contaminants we find outside, we also have indoor contaminants. There are pollutants typical of homes such as dust, spores, moulds, and those produced by human activities like cooking and house-cleaning, which contribute to the release of additional damaging substances.

What’s the aim of the rules laid out in the SIMA Indoor Air Quality document?
In Italy, while for outdoor air there are laws that regulate the subject matter, there is no comprehensive set of rules that govern indoor pollution. Of course individual citizens should also convincingly adopt their own virtuous behaviours because the environment does not belong to states and governments, but to each one of us.

 

One way to improve indoor air quality is using biobased construction materials. For example, the European Isobio project is studying natural materials, like hemp and straw. By “breathing”, they offer better ventilation and help reduce damp. What benefits could this field of research provide?
There are no doubts that bioarchitecture and bioconstructions can contribute to improving the overall well-being of those who spend a lot of time indoors, and can offer practical help to improving the energy efficiency of buildings.

All this has a positive effect on the amount of harmful emissions from the heating systems of our homes, which are the biggest source of thin particulates in large towns. Moreover, there are many other entrepreneurial initiatives that, thanks to new compounds, are seeking to improve air quality. New green roof tiles and a new antismog paint are some examples.

 

What is meant by environmental medicine?
Environmental medicine deals with prevention, diagnosis and treatment of disorders that may be related to “environmental factors”. This is a sector that encompasses various disciplines such as biomedical sciences, environmental sciences, legal sciences, economic science, social and political science, material sciences, and construction science.

Environmental medicine may be considered to be the medical branch of the much broader field of environmental health, which, in turn, is a part of public health. It is not very well known in Italy, but it has been explored by WHO and is a common concern in the US.

 

Even though it is a fundamental issue for our health, it seems there is not enough attention to environmental medicine in the media of your country, Italy. Are there sensitivities around these issues?
The media need information that has been verified and certified, and this type of information can be provided only by associations and bodies that have strong ties with research and science. Releasing information through the media about initiatives aimed at informing the people or that intend to be a stimulus for politicians and institutions, requires players who are credible and well-known.

So I don’t think it is about hurting “sensitivities” but rather about the fact that so far the few people who have dealt with this issue before us, have restricted themselves to a specialised medical approach. Environmental medicine is instead a multidisciplinary field, aimed at preserving human health and at avoiding that our surroundings may become an environmental factor that causes diseases, injuries and premature death.

 

By Elena Veronelli

Photo credits: Joshua Ness

23 January 2017

Homes storing CO2, just like trees

Houses built with bio-based materials, such as timber, straw and hemp, act as CO2 banks. Experts explain how citizens can become custodians of atmospheric carbon dioxide and thus help reduce air pollution

Domestic efforts play an important role in curbing global warming. Besides producing and using renewables, homes can also act as banks that store CO2. This innovative building model exploits bio-based materials, such as timber, straw and hemp, which act as “carbon sequestrators.”

Carbon is banked through photosynthesis made by plants during their lifetime. “Photosynthesis is the means with which plants absorb atmospheric CO2 molecules, and split them into their component atoms. The carbon atom is retained making complex organic sugars that are the building blocks of the cellulose, hemi-cellulose and lignin found in plant cell walls. The oxygen atoms are released back into atmosphere as a by-product. Therefore, photosynthesis converts atmospheric CO2 into carbon-based materials that we can use to build and insulate our houses”, says Finlay White, expert in low energy “passive” buildings.

When plants die, the ground absorbs the stored carbon dioxide, which then finds its way back into the environment. However,  if we use bio-based materials in construction, the CO2 remains “imprisoned” in the buildings made.

But how much carbon dioxide can be stored in a carbon sequestration house? White explains that “depending on the extent of the renewable materials used, the gross amount of CO2 equivalent stored could be as much as 55 tonnes for a typical 80m2 house. Such dwellings would typically use timber framing for the superstructure and for the internal walls and floor, straw bale insulation in the roof, timber for the cladding and finishes, and other bio-based materials for use elsewhere.”

“The gross amount is the actual CO2 absorbed by the bio-based materials used in the building. The net amount will need to take account of the energy used and subsequent CO2 emissions associated with dealing with the forests and crops, and turning the materials into useful building products and delivering them to site. This is known as embodied carbon”, he adds.

“Therefore the calculation for a bio-based house will be the gross CO2 captured minus the CO2 emissions embodied in making the house. A typical 80m2 bio-based house with a gross CO2 capture of 55 tonnes might well mean a net amount of 33.6 tonnes.”

White works for the Bristol-based green technology firm Modcell, which contributed to the construction of what they claim to be the world’s first commercially available houses built using straw (more info in this BBC report).

They are also collaborating with the European project Isobio, which is developing “new products that include compressed straw board that can replace plasterboard, cereal fibres combined with bio polymers to make components for door cores etc.”, says White, “Once a designer becomes aware of the use of bio-based materials, the potential for their use expands rapidly.”

Carbon sequestration houses still remain a niche market in Europe.

Callum Hill, senior visiting research fellow at the University of Bath, another Isobio expert in the field, points out that “the building industry tends to be very conservative in its approach and prefers to use what it is familiar with. Bio-derived materials are often perceived as being perishable, flammable and short-lived. These perceptions are not supported by facts”. Compressed straw bales used for building envelopes, for example, are not flammable because they contain less oxygen.

Hill thinks that governments should recognise this alternative storage of atmospheric carbon dioxide and “provide a financial benefit for custodians of it. “It is a way of storing atmospheric carbon dioxide that can be readily achieved and without financial penalty (unlike carbon capture and storage)”, he says, “This is something that can be done to the benefit of society and the environment. Anthropogenic carbon emissions are undoubtedly changing the climate and these will have huge financial implications”.

 

By Luigi Serenelli

17 November 2016