In many countries there are urban areas with already more than one million inhabitants. And with that came a phenomenon of large urban agglomerations that causes irritation of mucous membranes, lung disease and even heart attacks and cancer, but that nevertheless in these cities is being paid very little attention: the poisoning of the air by motor vehicles.
Part of the problem is that the human being is the most adaptable of all: those who live in these cities are already accustomed to the smoke of their streets, and they view it as normal. However, we just have to ask an outsider and to the surprise of many locals she or he would probably opine that in these cities there is more smoke coming from vehicles than in large megapoleis. It is that something is wrong.
Today's motorcycles, cars, vans or trucks operate by burning petroleum fuels whose molecules contain carbon and hydrogen. When burned with oxygen from the air, carbon forms CO2 and hydrogen forms H2O. The CO2 is the gas that causes the greenhouse effect, but on the other hand, it is non toxic to humans, and in fact is the gas that is used in soft drinks. The H2O is simply water vapor. So the question remains why the vehicles' exhaust is toxic.
The problem is that these gases are not burned in the laboratory, but inside roughly tuned engines. The combustion is bad, which makes other substances appear, avoidable and unnecessary, which are toxic.
Carbon monoxide or CO is the CO2 that lacks oxygen, and is highly toxic. Within the human body it attaches to red blood cells and prevents the blood from carrying oxygen to the brain and other organs, causing a "choking from inside." It cause headaches, dizziness, nausea, and with prolonged exposure, death. There were many cases of people who have died in closed garages because of this gas. It is odorless and transparent, which makes it even more dangerous.
Nitrogen oxides are formed in the engine due to high combustion temperatures, which are sufficient to combine atmospheric nitrogen with oxygen. Then, after suffering several chemical transformations they become ozone, which corrodes the lungs.
The unburned hydrocarbons may be vapors or particles. Vapors come directly out the exhaust pipe, or from the fuel tank in a vehicle parked in the sun. Unburned hydrocarbons irritate the skin and eyes, but if they are in the form of particles the situation is much more serious.
The particles are nothing but ash from a combustion that is not complete, and this ash is what we see as black smoke from vehicles' exhausts. Relatively large particles are trapped in the nose and throat, and then expelled, but the finer particles pass these natural barriers and then this soot reaches the lungs. The finer the particles, the deeper they fall within the bronchi and alveoli, from where they can not leave. This soot is related to the worsening in the health situation of asthmatic or allergic people. With the passage of time it can cause emphysema. The particles are also usually coated by other substances that cause lung cancer. Furthermore, an inefficient respiratory system can generate cardiac complications. And in 2002, Abderrahim Nemmar and others demonstrated experimentally that the finest particles can pass to the blood and be distributed to other parts of the body.
Of course, that vehicle exhaust is poisonous is something that everyone has known for many decades. Many have been fortunate that their large cities are not surrounded by mountains (unlike Santiago de Chile or Los Angeles, USA). This allows air circulation to be good enough and the cities get cleaned. However, even then there are days when this circulation is poor, and if it's hot and has not rained for several days, the situation worsens. Just a datum: a study published in 2002 by the World Health Organization estimated that in the yert 2000, 800 000 people died worldwide of particles thrown into the air.
But since longtime ago engineers, due to public pressure and forced by governments, have been improving vehicles so that today the situation in many countries has greatly reversed. The first vehicles with antipollution devices appeared in California in 1966, and by 1968 they were already mandatory in the rest of the United States of America. Years later Western European countries followed suit and more recently some big Latin American countries. Throughout these four decades antipollution laws have become more stringent and therefore vehicles have adopted increasingly less dirty technologies and fuels.
Now, the problem is that in many countries these laws are almost nonexistent, and many manufacturers have chosen not to sell them the vehicles with the latest anti-pollution technologies, and neither fuel distributors offer them the same fuels they sell to U.S. and Europeans inhabitants. This does not make much sense, because what is good for Californians should be good for the others, and if something is bad for Californians it must also be bad for others. Unless someone thinks that these other people are worth less than Californians, which reminds me that since 1995 all cars that have been sold in the U.S. have airbags, but in many parts of the world this is not so even today.
We can await authorities to do something, but if many people are into the new fad of altering the brake lights of their vehicles to be white and blinking when the law says these lights must be only red and constant, then we can not expect that pollution laws be enforced.
For those who have some conscience, some tips: first maintain your vehicle properly. Many vehicles are able to function and take us from one place to another even with the engine in poor condition, especially Diesels. But if you smell something in the exhaust that is a sign that it does not work well; if you see smoke is a sign that works very badly. Today even Diesel engines have systems that remove soot.
More maintenance means more money-spending, but ultimately also means less spending on medical bills. A note on what constitutes proper maintenance: this must be periodic, preventive, and not going to mechanic only when the car "dies" on the street. Mechanics should preferably be specialists in that brand and model, and it would be even more advisable if they are officially authorized by the manufacturer. It is not recommended to repair everything with duct tape.
Refueling at the first gas station to appear on your way is risky: unfortunately fuel adulteration is very common in many regions. If after refueling the engine is knocking like having stones inside, or if you note a lack of power or note smokes, it may be an indication of adulterated fuel. You can also ask your mechanic if she or he notes anything unusual. If you already identified reliable gas stations, prefer them always.
Prefer vehicle models that are also exported to countries with strict controls, such as the United States of America. Find out if the importer actually offers a unit with similar technologies, and not just a version "for the Third World". In many markets, gasoline suitable for advanced vehicles has been sold for many years now. In the case of Diesel vehicles, "ultra-low-sulfur" fuels, less polluting, have already been developed: that they be sold in your area too is something that consumers can demand. And another detail: SUVs pollute more than a normal car, apart from being less controllable and more likely to tip over.
As there are many unconscious folks loose on the road, and in many parts unfortunately the laws seem to be just recommendations and not something of forced compliance, do not expect much improvement yet. So there is no choice but to try to protect yourself: it is best to always ride with the vehicle windows fully closed and leave the sunroof and the convertible for a picnic day. Always use the air conditioner or heater; if the air conditioning does not work or the vehicle is not equipped with it, probably at least the fan runs (although sometimes it may not be sufficient). And learn how to use properly the internal defroster/defogger for cold or rainy days, rather than rolling the window a bit down. Detail: almost all cars have a button or lever to close the external air intake: it is usually indicated by a diagram of a car with an arrow showing a circular motion inside (meaning recirculation or recycling). Keep this external air inlet in the closed position. If you are traveling for a long time or with several people, this entry should be opened occasionally, but never in uphills or traffic lights. There are already in the market luxury cars with special filters for these cases.
Avoid walking or running on sidewalks of those streets where is heavy traffic, specially if the traffic is uphills. If you live or work on streets like these, you should consider a way to avoid the smoke and gases getting into your home or workplace. When riding on buses, choose sitting on the seats to the right, and not near windows on the traffic side.
But ultimately, make no mistake: the real solution to this problem that is now reaching all parts of the world is the same as found in more advanced countries: new technologies and zero tolerance for those who insist in a poor maintenance of their vehicles.
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Originally published in ABC Color, on 27 August 2006. Map: Deaths attributable to urban air pollution, 2004. Note that figures for Third World countries are already similar to figures for the United States of America and Western Europe and in some cases exceeded them. Credit: "Health and Environment Linkages Initiative: Urban environments", World Health Organization, 2010, http://www.who.int/heli/risks/urban/urbanenv/en, accessed on 12 August 2011. Map Copyright © 2010 World Health Organization, reproduced with permission.