Toxic Air

Shutting the front door behind you after a long day on earth may not necessarily give you the comfort you need. Where does your mind take you when I say 'air pollution'? ..........factories? busy mothrways? centres of bustling cities?

What about your sitting room? Your bedroom?

According to a recent World Health Organisation (WHO) report on selected indoor pollutants public awareness of air pollution in houses and offices is far behind that of outdoor pollutants. The report looks at the levels of chemicals in indoor air and what harm they can do. Understanding these chemicals is the first step in avoiding harm.

“We should look more carefully at what is going on in the indoor environment,” says James McLaughlin, a physicist at University College Dublin. Some products within buildings can be a source of pollutants, he says, and can cause long-term harm.

Chemicals which were a focus of the report include: benzene, carbon monoxide, formaldehyde, naphthalene, nitrogen dioxide, polycyclic aromatic hydrocarbons, radon, trichloroethylene, tetrachloroethylene.

Not everyone is equally susceptible to these gases. According to the report individuals vary widely in their response to exposure to chemicals. "Each person has a pre-existing status – defined by, for example, age, sex, pregnancy, pulmonary disease, cardiovascular disease, genetic make-up and lifestyle."

Let's have a closer look at one of the pollutants.
Benzene

Indoor sources   

Benzene is a genotoxic carcinogen in humans and no safe level of exposure can be recommended. Benzene in indoor air can originate from outdoor air and also from sources indoors such as building materials and furniture, carpets, paints, attached garages, heating and cooking systems, stored solvents and various human activities. It’s also in tobacco smoke. Indoor concentrations are also affected by climatic conditions and the air exchange rate due to forced or natural ventilation.

Pathways of exposure

Inhalation accounts for more than 95–99% of the benzene exposure of the general population, whereas intake from food and water consumption is minimal. A study carried out in the United Kingdom estimated a daily dose of benzene of 70–75 μg/day for rural non-smokers and 89–5 μg/day for urban non-smokers. Most of the children’s exposures were produced in the home. The daily dose rose to 116–22 μg/day for urban passive smokers and to over 500 μg/day for urban smokers.

Another European study estimated a daily inhaled benzene dose of 102 μg/day, where 36%, 32%, 2% and 30% of the exposure was attributed to indoor home, indoor work, outdoor and in transit, respectively. Indoor concentrations measured in offices are generally higher than those measured in residential buildings, owing to the presence of sources such as photocopiers and printers. Mean concentrations in discotheques/clubs and pbus are genereally higher than in restaurants and other public spaces.

Relatively high benzene concentrations indoors have been attributed to sources such as incense burning, with benzene concentrations peaking at up to 117 μg/m3; new buildings (e.g. up to 30 μg/m3); attached garages (e.g. 16–19 μg/m3); tobacco smoke (e.g. 16–193 μg/m3); cleaning (e.g. 13 μg/m3); painting (e.g. 9–13 000 μg/m3) and using a kerosene stove (e.g. 166 μg/m3).

What you can do to minimaze the exposure

There are basic measures you can take to help yourself, your family.

• Ventilate your house very well every day. It's not a good idea to make your house airtight.
• Minimaze the amount of synthetic cleaning products. Lemon, soda and vinegar are the best and safest cleaning products.
• New materials and products can give off the chemical for months, especially when high temperatures are combined with high humidity. Be mindful of that.
• Avoid products with volatile organic compounds if possible.
• Ventilate the car before you get in.
• Don't smoke at home.
• Avoid burning incense at home.

Irish Times article on indoor pollutants