Pollution Sources

Pollution Sources

Human activities – the source of indoor air pollution

Every step you take dislodges thousands of dust particles. The so-called house dust is the endproduct of slowly disintegrating material in furniture and bedding, or is made up of animal hair, insect droppings, fungal spores, bacteria and pollen. Even your skin is a source of airborne particles. In your lifetime you shed approximately 18 kg of tiny skin scales. The turbulence you create while just walking is enough to lift the dust off your clothes and off household surfaces and adds to indoor air pollution.

Usually you won’t see these floaters – they are too small. But, once they settle and accumulate on, let’s say, dark lacquered furniture surfaces, you will certainly see them. The best cleaning practices won’t completely eradicate the dust, though. The Warrant Officer at the Officer Training School knew this. He was wearing white gloves to prove to me that my cleaning practices were way below standard. “Do it again, son.” I learned that a feather duster, for example, may catch some of the larger particles but will only place the finer dust onto surfaces where white gloves are required for its removal.

Most vacuum cleaners won’t catch the fine particles and gases that are dangerous to our health.

The vacuum cleaner does offer some help. Nevertheless, this device is only as good as the filter bag inside. The popular varieties of vacuum cleaners work on the principle that they suck air from the outside, force it through a dustbag and then guide it back into the room via an exhaust. The dustbag system is a trade-off between the ability to catch fine particles and the suction power. A bag with very fine pores catches many pollutants but reduces suction power. On the other hand, a bag with larger pores may give the vacuum cleaner an impressive suction power but can’t filter fine particles. In other words, you won’t have much hope catching the very fine particles – just the size that is most dangerous to your health. Recently some vacuum cleaners came onto the market that employ different systems of catching dust. Manufacturers claim that they can remove most microscopic particles.

I vaguely remember my mother cooking on woodfire stoves. Or was it coal? In any case, I was often entrusted with the thankless task of cleaning the ashtray. “Don’t make a mess!” “Oops.” Times haven’t changed much for about half the world’s population, which still relies on burning of wood and coal for cooking and heating. These unprocessed sources of energy emit high levels of sulphur dioxide, nitrogen dioxide, carbon monoxide and particulate matter. This unhealthy indoor air often mixes with pollution from the outside.

In the introduction I have already mentioned that the so-called developed world isn’t much better off. Open fire places, gas cookers, heaters and tabletop charcoal grills are major sources of indoor air pollution. At the moment it is also very fashionable to burn scented candles, incense sticks and aromatic oils. Holy smoke? Not quite so holy, more like nasty black soot. Regardless of the origin, the very fine particles, seen as smoke, are the result of incomplete combustion. In other words, not enough air reaches the flame. The particles have the unwanted ability to deposit in the tiny air sacs of our lungs and remain there for a long time, sometimes for ever. They may, at the very least, aggravate respiratory illnesses.

Secondhand smoke, or environmental tobacco smoke (ETS), contains 4,000 substances, of which 40 are linked to cancer. It is a mixture of the smoke given off by the burning end of a cigarette, pipe, or cigar and the smoke exhaled from the lungs of smokers,’ so the US Environmental Protection Agency defines it. The agency estimates that approximately 3,000 non-smoking US citizens die  each year as the result of passive smoking. Do I have to mention that secondhand smoke negatively influences indoor air quality? I just have.

Let’s do some housekeeping. Good idea. This should reduce the levels of potentially harmful pollutants. Yes, but keep in mind, cleaning materials and their fumes often contain toxic chemicals. Cleaning agents, disinfectants, insect repellents, air fresheners, paint etc. contain chemical compounds that, in the average, increase the level of a particular substance in indoor air by 2 to 5 times above that of outside air. The levels are many times higher shortly after certain activities and can irritate the eyes, nose, throat and lungs; or cause headache, nausea and other toxic reactions.

“Achoo!” Your guest sneezes while your cat innocently tries to make itself comfortable on your visitor’s lap. “I’m allergic to cat hairs,” your guest explains. Very politely you point out that its not the hairs that trigger the allergic reaction but the protein in the dander, urine or saliva of the cat. “Whatever,” comes the reply and your cat is on the way to the great outdoors. You don’t want to push the point and, therefore, don’t explain that not only cats can be blamed for allergic reactions. Dogs, hamsters, guinea pigs – in fact, any warm-blooded animal produces this type of protein. “Either the cat goes or I go!” that’s the ultimatum. Be warned. Even if you should remove the pet from your living rooms, the allergens remain in the air for months – in the carpet, in the curtains, in the bookshelves. You don’t have a pet? Well, perhaps you have a pest. The protein contained in dry droppings of cockroaches, for example, is also a trigger of allergic reactions and asthma in some people.

“I don’t have pests. I use insect sprays quite regularly. Also, an environmental pest manager, (isn’t this a cute name for a bug zapper?) sprayed my house only a few weeks ago.” Cockroaches, silverfish, spiders, fleas, ants – yes, they die from the deadly cocktail of chemicals. We use insecticide to kill insects, termiticide to kill termites, rodenticide to kill rodents, fungicide to kill fungi, and disinfectant to kill germs. They are all harmless to humans, unless… Do you read the warnings on the back of the spray can? Do not deliberately sniff this product, sniffing may harm or kill you, that’s what it says on the back of my can. A recent study in the US suggests that 80% of all exposures to pesticides occurs indoors. 79,000 US children were involved in pesticide poisoning and exposures in 1990. Do I need to say more?

You may also contribute to indoor air pollution by accident. The bottle with the colorful cleaning agent spills onto the floor and, despite your best efforts, releases its toxic fumes for many days. The old story of the bathtub overflowing while you are on the phone with your mother, isn’t so far-fetched either. Accidental water spillage, flooding and leaking roofs occur frequently. The damp house and its wet contents are a breeding ground for mould and bacteria. A fire will leave its soot and odors behind, long after it is extinguished. If it is not the water or fire that does the damage, then it could be an eager handyman. Remodelling or demolishing parts of the house releases dust and fibres. Some of them may accidentally find their way into living rooms.

 Building components and furniture are pollutant sources

Unless you have read my book before you built or bought a house or unless you were already very conscious about indoor air quality, your new home came with many ‘inbuilt’ sources of air pollution. Even if you plan for the future, you will encounter many obstacles to find indoor-air-friendly building materials and furniture, and you may have even more problems finding an architect or builder with the relevant knowledge. Having said that, with the knowledge you gained by reading this book, you can at least minimize the risk.

building_componentsSolid wood is expensive, shrinks, warps, splits etc. The solutions is to glue together sheets of wood fibres to prevent these disadvantages from happening. The end product are particle boards and plywood for wall and ceiling panels, sub-floors and furniture. To make them look good, the manufacturers glue a thin veneer of plastic of boundless designs onto the surface. Today you won’t see much difference between a synthetic wood of marble design and the natural product. But, unless you have the ‘real’ thing, the surface finishing and the glues are chemical compounds.

Petrochemicals belong to a large family of chemicals that were chiefly derived from petroleum, natural gas or coal. The endproduct can be soft, such as sealants or adhesives; or flexible and hard, such as electrical insulators and switches, bathroom and kitchen furniture, components of appliances, plumbing material – the list is long. Manufacturers add further chemicals to maintain the softness, to harden the product or to stabilize the compound. In general, building products containing glues, sealants and plastics, emit gases that contribute to indoor air pollution. Proof? Some of the gases in soft compounds you can smell immediately. Harder compounds release gases more slowly and the proof is only visible after a few years, when the product ‘dries-out’ – becomes brittle. Chemicals, such as formaldehyde, benzene and vinyl chloride, disappear into ‘ thin air’ – literally. That’s not so good, if the ‘thin air’ is your indoor air. Heating or exposing the material to ultraviolet radiation accelerates the process.

By now, the use of asbestos as building material is, hopefully, banned in every country. Houses built until the 1980s (the year differs for every country), however, may still contain products made form asbestos. Asbestos is a very durable material and, therefore, was popular in the manufacture of shingles and wall panels. These were the obvious choices. But, because asbestos is also fire retardant, it was extensively used as insulation in heating systems. Even more out-of-sight was its use as backing on vinyl floor coverings or as texture in wall paint. Asbestos is harmless unless it is damaged. Then it releases its fibres and becomes dangerous to your health.

Carpets are a pollution source. Toxic gases may arise from: the synthetic fibres of carpets; the products used to install it, such as underlays or adhesives; carpet treatment, such as mildew resistors and stain proofing; and from chemicals used in the cleaning process. A freshly laid carpet is of particular concern and rooms should be well ventilated before occupation. Carpets, curtains and other decorative fabrics may also store chemical and biological pollution. Chemicals in deodorants and pesticides, or natural contaminants such as dust mites and fungal spores, settle in between the fibres of the material and will get airborne again once disturbed.

If you feel intensely excited and happy, it can be the result of choosing the right color, or it can be the first sign that you put your nose a little too close to the can of paint. Hardly any other material, used in the building industry, makes the presence of its volatile ingredients felt as fast as paint does. Open a can and you can instantly sniff the smell of solvents. Euphoria may not be such a bad reaction, but symptoms, such as headache, nausea, dizziness and fatigue follow if you don’t get your nose out of the paint. Wouldn’t you like to use paint without harmful chemicals? A small number of paint manufacturers react to the demand and produce non-toxic or low-toxic paint. I hope we will see ingredient labels on paint cans very soon.

Ventilation systems, air-conditioners and humidifiers dilute and filter harmful indoor air or provide climatic comfort to occupants of multi-story office buildings. These appliances slowly find their way into modern homes and are now seen as essential equipment in some regions. If the mechanic device is poorly designed or maintained, however, it won’t improve indoor air quality. It may just do the opposite.

What is the right amount of fresh air that needs to replace the air inside a building? The building code changes over the years. What was seen as adequate a few years ago may not be sufficient today. Where does the air come from? Air intakes shouldn’t really face a busy road, for example, where they may catch vehicle exhausts. Air-conditioners extract excess humidity from the indoor air. Several liters of water will drip from the system on a humid day. Where does the water go? Standing water in drip trays or moist walls and soil can be the source of biological contaminants: fungal spores and bacteria. Dirty and dusty cooling coils, baffles or ductwork may also act as breeding grounds for fungi and germs. Biological contaminants trigger or aggravate a variety of illnesses. Kill the buggers! Be careful, though, where you spray the toxic biocide. Ensure the chemical spray and its fumes aren’t picked up by the air intake of the appliance and then distributed through the house. Of course, this caution is valid for anything else that may be placed near the air intakes, such as paint, sealants or cleaning products.

Have you ever wondered where that foul smell comes from. Drains from your shower, sink or bath tub have a u-shaped trap that is usually filled with water to prevent sewer gases from reaching the room. If the drain isn’t used for a while, the water evaporates and no longer traps the gases. I hope I don’t have to tell you what the sewer gases are composed of. Good, because I don’t know. I leave it to your and my imagination.

A poor building design or building practice can significantly contribute to indoor air problems. Dripping water or sewer pipes, condensation along cold-water pipes or poor ventilation in crawl spaces underneath the house can promote excess growth of biological contaminants. Wherever there is moisture, moulds will grow: in walls, behind wall paper, on timber and bricks, in carpets etc. Lock-up garages are often part of the house and car exhausts and petrol and oil fumes may enter the living area through cracks in the adjoining walls or along gaps around plumbing and electrical work. The same problem may arise from contaminated air in your home office or hobby room.

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