Did you know that chemical emission in the home is common? Emission from everyday products you wouldn’t expect: building materials, cleaning products, disposables and printers are common sources of internal air pollution. More and more is becoming known about the damaging effects of particulate matter (PM) but very little attention is yet paid to PM in our homes or what you can do to help combat it yourself. Plants are cheap and active air purifiers.

Why is the indoor climate becoming increasingly polluted?

There are two main reasons for the increasing problem of air pollution in homes, offices and care homes.

  • Building insulation is increasingly effective and even private homes are often mechanically ventilated. Cracks and draughts used to be perfectly normal. Ventilation was not a problem in those days!
  • We buy more and more disposable and complex cleaning products and equipment and also use more and more compound and glued construction materials. All these materials and substances contain particulate compounds.

In addition to which, people increasingly have indoor jobs, participate in indoor recreation and, therefore, spend more time indoors than they did 20 years ago. This certainly applies to children. Generally speaking, it can be said that we spend 80-90% of our time indoors and that the indoor air is 5 to 10 times more polluted than the outdoor air.

What are these substances and products?

Volatile organic compounds (VOCs) are toxic, colourless but sometimes odourous volatile substances in the air we breathe in, which are so small that the hairs in the nostrils do not trap them. They consequently enter the lungs where each substance can cause a different reaction. Research is ongoing to determine the exact damage, but every new study demonstrates that the risks are greater than we first thought. The products shown here ‘evaporate’ the toxins into the air. The concentrations are usually only small but if there is inadequate ventilation, they will remain airborne. Furthermore, and this is not shown in the table, we people constantly use the oxygen in indoor air and breathe out CO2. If a room has inadequate ventilation or too few plants in it, the air will automatically ‘get used up’.

Formaldehyde Xylene Toluene Benzene TCE Chloroform Ammonia Alcohol Acetone
Glues o o o o
Air fresheners o o o
Wall and ceiling panels based on plasterboard and/or chipboard o o o o
Bleach o
Cleaning products o o o
Cosmetics o o
Copiers and laser printers o o o o
Curtains and upholstery o
Facial cloths, kitchen paper, tissues o
Carpet o o o
Gas fires o


This list is by no means exhaustive, neither does it include all substances emitted, but it does give some indication of the kinds of materials and substances concerned. Everyone will have a number of these products at home. Therefore, everyone will be exposed to the harmful effects. You can’t see these toxins but you can sometimes smell them. Acetone in nail-varnish remover or ammonia and chlorine in cleaning products.

Even if you can’t smell the polluted air, we all know what it’s like; we can all remember what the air in a full classroom was like at the end of a gym lesson. Spend a few hours in a meeting room and you’ll often find the air equally unpleasant. You’ll find it hard to concentrate and long to breathe in some outdoor air. If that’s how you feel, then you’re in a room with polluted air.

Plants as air purifier

Hardly anybody thinks of plants as active air purifying mechanisms. But they are just that. Plants provide the world with oxygen and that applies to indoor plants too. Indoor plants continuously convert CO2 into oxygen, just like the trees outside. So the air in a room with plants will last longer than in a room without. Research has also demonstrated that plants are able to actively filter the VOCs listed above out of the air. Not all plants tackle all substance to the same extent, some plants are even considered ‘specialists’ for specific substances.

The fern (Nephrolepsis exaltata) is a Formaldehyde expert. Areca palm is the specialist in combating Xylene and Toluene, and the most effective way to rid a house of Ammonia is to have a Lady palm (Rhapis exelsa). The Spath or Peace Lily (Spathiphyllum), finally, is very effective for removing Acetone.

For more information about which plant does what, read the article Grow your own fresh air. Here, you will also find the link to the book by W.C. Wolverton, which includes a top 50 of the best air-purifying plants to have in the home or office and how to care for them. There, and in the box on the right, we have listed links to online sites providing more information about the plants themselves.