Dishing the dirt on cleaning products
When Hong Kong mother of two Tracey Kwong goes to the supermarket, she takes time to read the labels on household products.
She avoids any product containing volatile organic compounds (VOCs) - gases or vapours that may have adverse short- and long-term health effects on humans and animals - such as isopropyl alcohol, naphthalene and methylene.
'Given my son Matthew's eczema, I look for VOCs in products such as laundry powder and body soaps,' says Kwong, 40.
Detergents, glass cleaners and floor washes help to keep the home spick and span, but the fumes they give out may also cause respiratory infections and even cancer.
A recent analysis of 25 top-selling US household products - from air fresheners to detergents, shampoos to dryer sheets - by Seattle's University of Washington found that they emitted an average of 17 VOCs each. It's a troubling figure, especially when there is no 'safe' level of VOCs.
A necessary evil?
VOCs are common in most organic solvents and appear in many consumer products because of their physical and chemical properties.
Formaldehyde, for example, a colourless gas with a strong odour, is widely used in manufacturing - car components, crease-resistant fabrics and furniture - because it is a building block for chemical compounds such as polymers. It is used in topical creams, cosmetics and personal hygiene products for its disinfectant properties.
Along with other VOCs such as tetrachloroethylene, hexane and toluene, its use in everything from hair spray to foam cushions has resulted in the concentration of VOCs being as much as 10 times higher indoors than outdoors, according to studies by the United States Environmental Protection Agency and other air quality researchers.
In Hong Kong, coupled with the air pollution, this can lead to a multitude of health problems.
'Outdoor air pollutants such as nitrogen dioxide and ozone can affect the quantity of VOCs in the atmosphere. Humidity also affects the volatility of VOCs. For instance, formaldehyde emission from materials is faster on humid days than on dry days,' says Dr Lai Hak-kan of University of Hong Kong's School of Public Health.
Reducing the risks
The effects of exposure to VOCs depend on several factors, including the toxicity of the chemical, its concentration in the air and the duration of exposure, says Professor Wong Tze-wai from Chinese University's School of Public Health and Primary Care.
While each VOC affects health differently, known physical reactions include eye irritation, allergic skin conditions, headaches, nausea and dizziness. Long-term effects include liver, kidney and nerve damage and cancer.
Kwong's daughter, Claudia, was particularly affected by the dual impact of poor air quality and VOCs.
'The air pollution in Hong Kong was bad enough. Then I noticed that when we used sprays or perfumes, Claudia would cough badly,' says Kwong. 'So I banned anything with sprays at home, even insecticides.'
Air circulation indoors helps.
'Good ventilation is the best way to reduce exposure to VOCs,' Lai says. Opening doors and windows and using exhaust fans can also help reduce VOC levels faster. In buildings that have been newly renovated or carpeted, airing is advised to allow VOCs to dissipate before moving in.
Those with green thumbs can cultivate indoor plants that are thought to help reduce VOC levels.
Researchers at the University of Technology, Sydney, have found that keeping a mixture of plant species, including Howea forsteriana (Kentia palm) and Epipremnum aureum (devil's ivy), in a closed chamber with no ventilation can result in a complete removal of VOCs in 24 hours. However, more research is needed to determine the most effective combination of plants.
The proliferation of 'green' consumer goods may lead people to think that they are safer.
However, in the University of Washington study, 19 of the 25 products tested carried claims such as 'green', 'organic', 'non-toxic' and 'natural' but were just as toxic as their 'non-green' counterparts.
This marketing practice, called 'greenwashing', has resulted in regulations in the US, Canada, Australia and Norway that prevent manufacturers making unsubstantiated eco-friendly claims.
While there is currently no worldwide standard for eco-labelling products, the Hong Kong Green Council is trying to establish local standards through the independent and voluntary Green Label scheme. So far, more than 100 consumer and industrial products have been tested and certified green (see www.greencouncil.org).
The Environmental Protection Department has also instituted regulations to limit the import and manufacture of consumer products with high VOC content.
The best way to mitigate the risks of exposure to VOCs, however, is to avoid or minimise the use of products that contain them.
'No product can be truly non-toxic,' Lai says. 'That's why we need to reduce VOCs as much as possible.'
For Kwong, avoiding VOCs has paid off. 'It has done wonders for Matthew,' she says. 'His skin has improved tremendously. He is less irritable and a more socially confident boy now.'