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Essay on Automobile Pollution
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Essay Contents:
- Essay on the Introduction to Automobile Pollution
- Essay on the Characteristics of Automobile Pollution
- Essay on the Impact of Automobile Pollution
- Essay on the Automobile Pollution Abatement
- Essay on the Legislative Measures for Automobile Pollution
1. Essay on the Introduction to Automobile Pollution:
With the cultural and technological revolution came the automobile, totalling 53 million in the 1950s, world automobiles in 2010 exceed 550 million. About 19 million vehicles are added each year to the global total. Automobiles have come to mankind as a mixed blessing.
While they enable mankind to conquer distances they also caused blatant destruction of the human environment, poisoned the atmosphere and made human beings vulnerable to several diseases, road accidents and fatalities. They are also a major consumer of oxygen.
The most affected group of people are the urban habitants, the city-dwellers, drivers, hawkers, vendors, shopkeepers and residents in the busy city area. But perhaps the worst sufferers are the traffic policemen, who remain close to the fumes of vehicle exhaust and must inhale large quantities of their toxic pollutants every day, while on duty. Roughly, a man breaths 22,000 times and inhales 16 kg of air, daily.
Automobiles are a ‘necessary evil’, while they have made living easy and convenient, they have also made human life more complicated and vulnerable to both toxic emissions and an increased risk of accidents. Urban people are most affected and amongst the worst sufferers are traffic policemen who are particularly close to the fumes of automobile exhaust.
Studies made in Jaipur, India, indicate that there is high rate of occurrence of respiratory, digestive, ocular and skin problems amongst the traffic policemen and a significant number of them become victims of lung disorders in the very first few months of their posting to a traffic department.
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Traffic policemen everywhere should wear ‘pollution masks’ for their own safety and to arouse public awareness of the risk of automobile pollution.
Urbanisation has a strong bearing on the travel demands in the country. Higher incomes, mobility, expanding cities and the proliferation of employment centres have increased the demand for motorized transport, resulting in a disproportionately high concentration of vehicles in urban centres.
Irrational distances between homes and places of work, greater incentives for private transport and inadequate and poor quality public transport has further aggravated the problem.
The Tata Energy Research Institute (TERI) estimates that of the total travel demand in 17 selected cities in India, the four metros generates nearly 56 per cent by 2010. This trend will negate any other efforts made to improve air quality and needs to be dealt with urgently.
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In 2005, for example, the vehicle population in India comprised about 25 million two wheelers, 5 million cars, jeeps and taxis and 4 million buses and goods vehicles. Of these 40% were concentrated in Delhi, 25% in Mumbai and 15% in Kolkata. However, the overall vehicular population distribution of major categories in metro-cities are depicted in Fig. 21.1.
The level of motorization in Asian countries has been growing at different rates and has been influenced by increasing affluence and population growth. The number of vehicles in Asia will continue to grow, with the possible exception of Singapore and Hong Kong, where active controls have been implemented to limit the number of vehicles and promote alternative public transport options.
The majority of additional vehicles will be new ones, while for some countries a substantial number of reconditioned vehicles, for which there is no adequate emission control in place, will be added to the fleet.
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These are often buses or other public transport utility vehicles imported from other Asian countries where stringent in use emissions and safety requirements have made the engines obsolete. These are typically vehicles which are used intensively and not maintained very well. At present, vehicles in major industrialized Asian countries are being used for longer than was considered would be their normal useful life.
Two wheelers play an important role in Asia as they are accessible to a larger portion of the population who cannot afford to own a motor vehicle. This region has a very large population of two and three wheelers that dominate the emissions inventory for some compounds in most major cities.
More than 75 per cent of the world’s fleet of two wheelers and three-wheelers is in Asia. China alone accounts for approximately 50 per cent and India for 20 per cent of the world’s fleet of two wheelers.
In some cases, the inclusion of motorized two wheelers in total motorization rates brings these motorization rates up to the same level as cities with much higher average per capita (or per household) incomes.
For example, when motorized two wheelers are included, Mexico City, with a GDP per capita 10 times higher than Chennai, has a lower motorization rate than Chennai. As the income of individuals rises, the two wheeler becomes accessible and therefore accelerates the motorization process in Asia.
A high proportion of the population in Asian cities currently depends on public transport and non- motorized forms of transport such as walking and cycling as the main mode of transport. As cities grow in area and decline in average density, the relative share of trips made by public transport and the absolute number of non-motorized trips are decreasing.
The rising trend in car ownership and decline in public transport as an alternative to the private motor vehicle has varying effects on different countries often affecting the poor, elderly and disabled who are dependent on public transport for their personal mobility. The continued growth in motorization in Asia will further exacerbate current levels of traffic congestion and result in increased motor vehicle emissions.
2. Essay on the Characteristics of Automobile Pollution:
The internal combustion engine has made an important contribution to the air pollution.
The main pollutants released by engines are:
1. Carbon monoxide
2. Un-burnt hydrocarbons
3. Nitrogen oxides
4. Sulfur oxides
5. Lead compounds
6. Smoke
7. Particulates
8. Odour.
Among the important constituents of the petrol engine exhaust are carbon monoxide, un-burnt hydrocarbons, nitrogen oxides, particulates and lead, while diesel engine emits un-burnt hydrocarbons, nitrogen oxides, sulphur oxides, smoke and odour.
The vehicle population is growing rapidly throughout the world and emissions from transportation will increase in proportion, if unchecked.
The comparison of traffic situation in three metros are given in Table 21.1:
Among the list of automotive pollutions serial numbers 1 to 5 is decidedly dangerous to human health while serial nos. 6-8 are only nuisance.
A comparison of exhaust constituents of petrol and diesel engines are given in Fig. 21.2:
The pollutants like carbon monoxide, un-burnt hydrocarbons and nitrogen oxides have been the main targets of exhaust emission regulations throughout the world, because of their potential health hazard.
To obtain the mass of exhaust emission from a vehicle, it is necessary to measure the concentration of the pollutants in the exhaust and the mass flow of air through the engine. On the whole, diesel engines are less of a health hazard than petrol engines, although the smoke and odour are certainly a nuisance.
Thus automobiles are mobile polluters and petrol vehicles are the worst. The highest emission rates occur during motor idling, deceleration and at slower speeds (Table 21.2).
Road intersections, especially those that are traffic light controlled and sharp turns in cities slow down the traffic and enhance the pollution emission rates. During idling and at slow speeds the greatest emission is of carbon monoxide and hydrocarbons.
Ozone, the principal ingredient of urban smog, is formed when energy from sunlight causes hydrocarbons to react with Nitrogen oxides (NOx). Sulfur dioxide (SO2), Lead (Pb) and the Suspended Particulate Matter (SPM) are the other toxic pollutants from automobiles, all of which make the urban environment particularly unpleasant for the city dwellers (Table 21.3).
3. Essay on the Impact of Automobile Pollution:
Automobile pollutants have multiple effects on various environmental variables (Table 21.4). Among them the effect of auto-emission on plants and human health is most predominant.
(a) Physical Effects of Automobile Emission on Human Health:
The polluted gases as emitted from automobile viz., CO, NOx and hydrocarbons have profound effect on human health. In addition secondary pollutants which form smog is considered to be the most severely affectively pollutant to human health (Table 21.5). In urban environment, automobile emission constitute the major pollutant source.
(b) Physical Effects of Automobile Exhaust and NOx on Plants:
Plants that were kept on open field in close vicinity to busy highways reacted upon the pollutants with increased chlorophyll, sugar, free amino acid contents, an augmented ethylene production and peroxidase activity, a decreased β-carotene, ascorbate and auxin concentration and changes in fatty acid metabolism.
Automobile exhaust in concentration up to 1,000 µl/1 leads to a reduction in photosynthesis and impairment of stomata of Picea, Abies within only 15 min of treatment.
These toxic effects of the automobile exhaust were traced back to NOx, that are solubilized in the water saturated nitric acid (HNO3). These compounds immediately dissociate into nitrate, nitrite and protons so that nitrate and nitrite accumulate in mesophyll cells of treated plants.
This, in turn, induces the synthesis of a number of enzymes viz. nitrate (NR) and nitrite reductase (NiR) as well as glutamine synthetase (GS) and glutamate synthase (GOGAT). The effect of NOx on photosynthesis and dark respiration is highly dependent on exposure time and doses.
As a rule, a short-term treatment with NOx at concentration beyond 0-3µl/1 increases chlorophyll content, dark respiration and net photosynthesis. Increasing concentrations of NOx above 0.5µl/1 affect these parameters negatively.
4. Essay on the Abatement of Automobile Pollution:
Over the years, the automobile population is increasing and thereby contributing substantially to the total urban air pollution load. For abatement of such pollution, number of practices already adopted in various countries.
These include:
(i) Imposition of auto-emission standard i.e. declaration of permissible limit of pollutants emission by the different cars;
(ii) Adoption to newer techniques for reduction of emission from engines.
The details of car emission standard as practiced in India and Europe is given in the separate Tables 21.8 & 21.9:
There is wide range of techniques which can be applied to the intake system, the combustion chamber and the exhaust systems of petrol and diesel engines to reduce exhaust emissions (Fig. 21.3).
The outline of its activities is given as:
1. A positive crankcase ventilation valve is installed between crankcase and inlet system.
2. The fuel tank vent are connected to a coconister containing charcoal which absorb hydrocarbon ‘molecules.
3. The control of combustion chamber hydrocarbons emission.
4. The oxidation of CO and un-burnt hydrocarbons with air can be accelerated if a catalyst is present in the exhaust system. The most popular catalysts for vehicular exhaust emission control platinum and palladium. The catalyst can be introduced into the exhaust system by deposition on a ceramic honeycomb.
5. The emission of nitrogen oxides can also be reduced by attention to engine combustion.
MOEF proposed that the industry test emissions after fitting catalytic convertors, based on which government would finalize new standards for metros. Industry found that it could meet norms that were halfway between the 1996 and 2000 norms (Table 21.10) by using catalytic convertors.
While the CO standard is 8.68 gm/km for 1996 and 2.72 gm/km for 2000, with catalytic convertors the industry has been able to bring it down to 5.64gm/km. Similarly, HC and NOx has been brought down to 2.00 gm/km against the 1996 norm of 3.00 gm/km and 2000 norm of 0.97 gm/km. Encouraged by these results, new norms are now being contemplated for metro areas as an intermediate measure before 2000.
The automotive industry is unhappy with the fact that MOEF has allowed the Petroleum Ministry to drag its feet for so long, while it was being hammered with conditions.
“To meet the new emission norms, the automotive industry will have to invest Rs. 50.000 crore in technology,” says Doshi. “Unleaded petrol will only be a small fraction in the total petroleum bill. The government does not want to do its bit and spend some money on improving fuel quality”.
Eliminating lead from petrol and reducing the sulphur content of diesel, will address the specific problems of lead particulate matter pollution and facilitate the use of catalytic convertors. But there are several other shortcomings in fuel quality in India which interfere with efficient combustion and foul up the engine.
Bad quality fuel leads to gum deposits on the engine which can clog up the carburetor passage and disturb the air-fuel ratio, thus leading to improper combustion. Vehicle manufacturers suggest that multifunctional additives be used in the fuel, in order to clean up the engine passages.
They claim that if fuel causes clogged passages, then engineering modifications like recirculation of blowby gas or exhaust gas for complete burning and cleaner crankcase emission will compound the problem, as the recirculated exhaust gas will leave behind more deposits.
The automotive industry complains that vehicles are tested with reference fuel, specifications for which have been separately notified. This reference fuel, a superior oil used for standardisation of refinery fuels across the country, is available only for testing purposes.
In 1996 National Environmental Research Institute, Nagpur (India) has developed a non-noble metal based, two-way catalytic converter technology for the control of exhaust emissions from petrol driven vehicles. The catalytic converter consists of a ceramic honeycomb support coated with a perovskite type catalytic housed in a suitable designed non-corrosive metallic housing.
The device can be fitted to the exhaust system of a petrol driven vehicle and thus this device catalytically coverts the harmful carbon monoxide (CO) and hydrocarbon (HC) emissions to carbon dioxide (CO2) and water (H2O).
The use of non-noble metal based catalyst makes the device cost-effective and lead tolerant as compared to the noble metal based catalytic converters.
The design of invented catalytic converter is shown in Fig. 21.4:
For diesel vehicle the institute also developed a diesel particulate filter (DPF) for control of smoke from diesel engine exhaust. This filter consists of an aggregation chamber followed by different grades of filters, housed in suitable designed non-corrosive, metallic housing. The device can be fitted to the exhaust system in diesel driven vehicle for effective reaction of smoke (Fig. 21.5).
Since 1990s, Ministry of Environment & Forest (MOEF), Govt. of India undertaken the following measures, for abatement of vehicular pollution:
1. Low-lead petrol with a maximum lead content of 0.15 gms/litre has been introduced throughout the country. This measure is expected to reduce particulate lead emissions appreciably.
2. Low-sulphur diesel (diesel with sulphur content of 0.5% or less) had been introduced in the four metros of Delhi, Mumbai, Kolkata and Chennai from 1.4.1996. Diesel with 0.25% sulphur is being supplied in the Taj Trapezium area from 1.9.1996.
3. Tighter emission standards for vehicles at the manufacturing stage, notified by the Ministry of Surface Transport, have come into effect from 1.4.1996.
4. Stricter emission norms for all categories of vehicles at the manufacturing stage are proposed to be notified by the Ministry of Surface Transport, which was proposed to be effective from 1.4.2000.
5. Norms for 4-wheeler petrol vehicles fitted with catalytic converters have been finalised and recommended to the Ministry of Surface Transport for notification.
6. A notification had been issued by the Ministry under the Environment (Protection) Act, 1986, on 2.4.96 specifying fuel quality for motor gasoline (petrol) and diesel. The Ministry of Petroleum and Natural Gas and the oil companies have been asked to meet the specifications as per the target dates.
7. An organised standard was setup for vehicles manufactured on and after 1st April 2000.
5. Essay on the Legislative Measures of Automobile Pollution:
The following legislative coverage are being practiced to regulate vehicular pollution in India:
Auto Fuel Policy’s Road Map for control of vehicular pollution from New Vehicles:
Indian cities have different climatic conditions, human population, different vehicle population density and source of pollution. The Indian cities with a population of more than one million people with high vehicle population and the cities in which prescribed standards are violated in one or additional parameters in 72 non-attainment cities, which require actions for vehicle pollution control ahead of the rest of the country.
Since the year 2000, India started adopting European emission and fuel regulations for four- wheeled light-duty and for heavy-duty vehicles. In respect of 2 & 3 wheeler norms, India is already ahead of most of the advanced world as far as the emission norms are concerned.
The road map for vehicular emission norms Bhart Stage II, III and IV is given in Table 21.12:
In addition, at manufacturing state noise limits for various kinds of vehicles are also imposed since 2005.
The details are given in Table 21.13:
