POLLUTION

Car pollution isn't just fuel, that's a fraction of the whole story; the biggest pollutants are turbulence and tarmac. They cause air, water, land and energy pollution.

Cars pollute the air by:

• releasing by-products of internal combustion - gasses and oxides which are the precursor chemicals for acid rain, toxic gasses, global warming gasses and tiny particulates that damage lungs;
• releasing by-products of friction - minute particles or oxides from many surfaces, cladding, engine, tyres, brake pads, enhanced lubricants (Teflon etc.); all vehicles, petrol driven or not, require these materials for resistance to speed & weather, because this is their function they cannot be biodegradable; but therefore they are not well processed by the human body when breathed in (reducing this pollution requires a reduction in friction, e.g. rail, and/or a reduction in vehicle numbers, e.g. car ban);
• causing constant turbulence by constantly and randomly disturbing the ground level air, thus, particularly in dry conditions, keeping particulates and ordinary dust aloft as air pollution;
• demanding constant production/replacement activity from a large separately air polluting industrial base (e.g. spray-painting and enamelling).

They pollute water through:

• industrial process demand, as with air pollution (more 1);
• runoff from city streets (usually into biologically crucial littoral and riparian zones adjacent to cities) of particulates and acidic/toxic solutions of the air emissions, particularly nitrous oxide (brown smog) which forms nitric acid rain;
• through their current fuel supply, oil, which is one of the most dramatic and serious water polluters through oil-slicks, leaks and tanker sinkings.

They pollute the land by:

• their space demand, the tarmac desert;
• industrial waste;
• disposal of car bodies and non biodegradable or toxic elements (vinyl PVC, sump oil, tyres are a major problem, they are unrecyclable and pile up in huge dumps that release toxic metals and other pollutants and burn, polluting the air , for months if they catch fire, etc.);
• denaturing of soils though aluminium and other mineral mobilisation because of acid rain, thus polluting water catchments.

They also cause energy, noise and heat, pollution:

• Traffic creates constant noise pollution, much of it background, as much from airflow and wheel rumble as from engine noise.
• Most human constructions trap heat, whereas greenery and trees disperse heat, converting some to matter and releasing some in transpiration. In car based cities the built area is larger, there is more tarmac than greenery, garages somewhat increase the built environment, trapping more heat and blocking breezes, so there is up to a 10 degree Celsius increase in heat between the city centre and distant countryside, and heat relief is less as breezes warm up over the city, sometimes rain-clouds are diverted sideways by the heat column. This is only a problem in hot conditions but it too discourages walking and increases car use, and triggers greater use of air conditioning, thus energy, industry and their associated pollutants, a problem set to worsen in the expected heatwaves of global overheating.

Last revised 2009-06-21

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