Recent announcement by the World Health Organization that Diesel Exhaust is a confirmed carcinogen only reiterates what has been suspected since long. An inconvenient question that may not have immediate answer is why it took such a long time to make this judgment while countries like the US, the EU, Japan and most developed countries with high automobile density have taken action long ago to curtail emissions by more stringent regulations leading to more and more efficient power trains, emitting less dangerous exhaust smoke. No matter how efficient the engine is there has to be some exhaust fumes and humans may have to live with this bitter reality for ever. Of course there are alternative options like electric cars or hydrogen powered engines with absolutely no emission of chemical gases but on economic consideration these may not become accepted options, at least for the next few years. Nearest to an ideal solution is the hybrid cars able to operate both with gasoline and rechargeable batteries which are becoming popular to some extent these days. If the present dilemma vis-a-vis diesel engine pollution was anticipated in time there could have been more practical solutions like expanding the mass transit systems and improved people moving systems that could have reduced drastically the automobile population. Developing countries like India ignored this problem for so long and this is going to haunt the country for years to come. The current policy of encouraging manufacture of more and more automobiles, in spite of lack of good road infrastructure and acute scarcity of fossil fuel sources to meet the galloping demand, does not seem to be logical or visionary. For example what is logic of pricing diesel significantly less than that of gasoline? Why is that more and more diesel powered cars are encouraged to be manufactured knowing well the hazards of the diesel exhaust? Nothing but lack of vision and insensitivity to the suffering of millions of citizens exposed to the danger.
Finding fault with diesel engine emissions is not a new development. It has been known for quite some time that Disel Particulate Matter, known more commonly as DPM, is a dangerous cocktail of chemicals which are harmful if inhaled from close quarters. DPM is mostly soot or unburned particles of carbon along with gases like carbon monoxide, nitrogen oxide, sulfur dioxide and others in varying concentration. These particles are so small in size, less than 10 microns, that they get through the throat, past the lungs into the deepest part of this organ capable of triggering asthmatic attacks, bronchitis, emphysema, heart disease and cancer. A part of the sooth can be nano sized particles which can penetrate to any part of the body into cells causing unpredictable consequences. Having a rough surface , DPM can attach to themselves different toxic gases carrying them through the cells of the body. The cocktail that is called DPM has cancer causing chemicals like antimony compounds, Beryllium compounds, Chromium compounds, Selenium compounds, Benzene, Pyrenes, Nitrobenzanthrone, , Styrene etc besides many potent Endocrine Disruptors like Phthalates, Phenols etc . Lot of data pertinent to the dangers posed by DPM to workers in mines or operators of diesel railway engines are documented but very little information is available as to the extent of exposure to the city dwellers. Millions of diesel driven trucks, tractors working in agricultural fields, lawn movers and other heavy machinery involved in infrastructure industry all pose risks of unknown magnitude. It is any body's guess as to what long term consequences this situation can cause to those exposed to millions of tons of DPM spewing into the habitat of humans beings, vitiating their living environment.
A pertinent question that rises in this context is whether millions of children being ferried into their schools every day are really in danger because of their exposure to diesel fumes emanating from the vehicles they use. In many developing countries there are no strict compliance vis-a-vis diesel engine performance standards and most of them continue to run for 15-25 years, spewing out the deadly, foggy, dark smoke, affecting people following them. As children are susceptible to chemical pollutants and manifestation of health disorders is faster in them, it is time that these aspects are looked into more critically on a global level. Similarly what is the fate of those who are in employed by the freight carriers, driving diesel trucks and heavy haulage vehicles?. Or for that matter the impact of diesel smoke on the health of urbanites exposed to the bellowing smoke of trucks, passenger cars, three wheelers plying 7x24 incessantly through the narrow roads in thousands of cities and towns in many countries? It is reported that in many hospitals in large metropolitan cities in india, there are special wards equipped with nebulizers for children who suffer regularly from breathing problems and lung related disorders, acquired from their day to day exposure to the automobile exhausts that pollute the environment. Is it not a fact that the proportion of asthma, a lung disorder, is predominant in cities compared to rural areas? Is the world moving towards a regime where lives of people are controlled more and more by the powerful pharmaceutical industry which manufactures medicines to deal with such disorders like asthma generating lucrative business opportunities?
According to prevalent standards the environment where humans live should not have pollutants like hydrocarbon, carbon monoxide, Nitrogen Oxide, DPM, Sulfur Dioxide, Lead and Volatile Organic Compounds( VOC). According to Environmental Protection Agency (EPA) of the US, air quality should ensure that particulate matter (< 10 microns) content does not exceed 150 microgram (mcg) per cubic meter during a 24 hour period while annual average has to be less than 50 mcg during a 24 hours period. The standards become more stringent when the particulate matter size goes down and their concentration in the air should not be more than 65 mcg over a 24 hour period and 15 mcg annually. Standards are also laid down for pollutants like CO, Lead, NO2, O3 and SO2. In India Emission Standards are laid down for CO2, Hydrocarbons, NO2 and Particulate Matters. Why there are different sets of standards for diesel driven cars and trucks is not understandable though it might be due to the technological limitations for improving engine performance in terms of emissions. In many countries equipping the automobiles with catalytic converters which are attached to the exhaust pipe has become mandatory. The Platinum-Palladium-Rhodium catalyst converts unburned hydrocarbon into less harmful gases like CO2. Increased use of biodiesel fuels incorporating plant oils has enable the industry to reduce sulfur content that contributes most to Laying down standards is one thing but enforcing the same becomes invariably the casualty. According to the present regulations, cars older than 2 years are required to be tested every 6 months for the prescribed emission pre-requisites and those failing them must retune their engines or take action to make necessary repairs to achieve positive results. Due to many practical and logistical limitations, testing has become more an exception than the rule!
One of the unknown factors that makes diesel engine emission more dangerous is what role some of the constituents in it play in spreading obesity which is an epidemic in countries like the US with very high automobile density. There are no scientific studies which have established any linkage between obesity and automobile exhausts but recent reports coming from credible scientific institutions linking endocrine disruptors (ED) with increased fat synthesis in the body need to be taken seriously. It is all the more disturbing when one realizes that ED at ppb levels can be active in derailing the functions of those hormones controlling many growth functions including lipogenesis. The deadly effect of DPM on lungs and bladder is indeed alarming but its influence on human body development also must be explored more seriously. The existence of obesogens which act at ppb levels is relatively a new development and as there are many chemical contaminants in foods consumed daily which have potential obesogen action, implicating DPM from fossil fuel driven automobiles may vitiate the programs targeted at bringing out people from the clutches of weight related disorders. Current philosophy of reducing calories and fat intake to achieve weight control can be seriously compromised if non-food factors like EDCs are also found to be contributing to this malaise.