Vehicular Emission in Indian Environment

Transcription

1 Vehicular Emission in Indian Environment R. P. Marvaniya P. J. Gundaliya Assistant Professor, Civil Engineering Department Associate Professor, Civil Engineering Department L. E College Morbi L. E College Morbi Gujarat Technical University Gujarat Technical University radhika.civil1988@gmail.com pjgundaliya@gmail.com Abstract Vehicle emissions are the gases released through a vehicle's exhaust system. Carbon monoxide, hydrocarbons and sulphuroxide along with nitrogenoxides and particulates are all harmful vehicle emissions that spew out of the exhaust gasses of an internal combustion engine. While catalytic converters were designed to reduce these harmful vehicle emissions, automobile designers worldwide to explore new methods of vehicle propulsion, such as electricity and hydrogen, that produce little or no pollution. Rapid, but unplanned urban development and the consequent urban sprawl coupled with economic growth have aggravated auto dependency in India over the last two decades. This has resulted in congestion and pollution in cities. In the present paper an attempt has been made to study the emissions problems of onroad vehicles. It is observed from the past studies that air quality in urban cities of India has degraded. The past studies revealed that two and threewheelers emitted about 64 percent of the total CO emissions and heavyduty vehicles accounted for more than 60 percent and 36 percent of the NOx and PM emissions respectively. However, these are varies slightly city to city as per vehicular types and fuel used. The Study has concluded that advanced vehicular technology and augmentation of public transit would have significant impact on reducing vehicular emissions. [9] Keywords Emission, Causes, Standards, Sources, Problems I. INTRODUCTION The different air pollutants due to vehicles can have effects at all the three levels local (e.g., smoke affecting visibility, ambient air, noise etc.), regional (such as smog, acidification) and global (i.e., global warming). The vehicles besides being the prominent source of air pollutants also account for a number of external effects, such as congestion, noise, accidents, road wear and tear, and barrier effects. Considering other country, it has estimated that in Santiago, Chile, wherever pollution concentration exceeds ambient standards, mobile sources or vehicles are the cause. Similarly, in case of Budapest, Hungary, transport is the dominant source of emissions except sulphur dioxide (SO 2 ), contributing 57% of Oxides of Nitrogen (No), 80% of lead (Pb), 81% of carbon monoxide (CO) and 75% of hydrocarbon (HC) emissions (Lehoczki, million in the year 2001 (i.e., an increase of nearly 87%). During the same period in India Delhi s population has increased by only 43% (from 9.5 million to 13.8 million) and roadlength by merely 14% (from 22,000 Km to 25,000 Km) respectively. Situation is similar across a number of cities in India and the developing world. This indicates the exigency of controlling vehicular pollution. Under this background this study suggests what the economics of vehicular pollution control is and what policy instruments / initiatives can be employed to control the vehicular pollution. For a prescription to yield desired results, it should hit the right source of pollution. The major difference between developing and developed countries lies in the fact that institutions are in place and information of health impacts are known to the policy makers. For developing countries, the challenge rests on devising suitable policy instruments that fully take into account the damage caused by the polluting source. It is to be stated at the outset that the note covers mainly the environmental consequences of transport and does not investigate the other important external effects of the sector such as barrier effect, congestion effect etc. [10] II. CAUSES OF EMISSIONS Vehicular pollution sources are not homogenous, as there is a complete range of technological mix. The mix could be in terms of fuel used gasoline or diesel or natural gas; or engine type 2stroke or 4stroke and/or a combination of these. Emissions from Gasoline Vehicles Gasolinepowered engines are of two types: 4stroke and 2 stroke. Table 1 gives the various sources of emissions in the two cases namely 4 stroke and 2 stroke engine. The exhaust emissions from gasolinerun vehicles consist of CO, HC, NO x, SO 2, and partial oxides of aldehydes, besides particulate matters including lead salts. The incomplete combustion of gasoline due to an imbalance in the airfuel ratio leads to emissions of CO and HC especially from 2stroke engines. The No x, however, are formed due to high combustion temperature and availability of oxygen and nitrogen in the combustion chamber, whereas aldehydes result from the partial oxidation of HC. In cities, majority of the pollution is emitted by vehicles consuming gasoline especially 2 and 3wheelers, having predominantly 2stroke engine. In either case it is a total loss system, as the oil is burnt along with the fuel. Since the burning quality of mineral based lubricating oil is very poor visàvis gasoline, major fraction of it that enters the engine either remains unburned or burns only partially. 38

2 TABLE I. EMISSION FROM GASOLINE VEHICLES Source Amount of Remarks Emissions (%) 4 stroke 2 stroke 1 Crankase 20 0 Carbureted airfuel mixture & combustion chamber past engine piston and ring and enter crank base to be discharged into atmosphere through vents 2 Evaporative Emissions 3 Exhaust Emissions Source: CPCB(1999) 20 3 Fuel vapours losts to the atmosphere from tanks and carburetor Exhaust gases emitted with pollutants through the tailpipe This unburned and partially burned oil comes through the exhaust and is responsible for smoke and SPM emission. The studies indicate that 2stroke engine s exhaust contains almost 1525% of unburned fuel (Pundir, 2001). In actual practice, the 2stroke vehicles require 2% concentration of 2 T oil i.e., 20 ml in a litre of petrol and even a modest 1% increase of oil, may lead to 15% increase in SPM besides visible smoke (CPCB, 1999). In most growing cities Delhi, Kathmandu, Chennai, Dhaka, Pune etc. gasoline or petrol driven vehicles comprise over 80% of the total vehicles registered. This implies controlling pollution from them can have significant payoffs. Emissions from Diesel Vehicles As diesel engines breathe only air, blow by gases from the crankcase (consisting primarily of air and HC) are rather low. Due to its low volatility, evaporative emissions from the fuel tank can also be ignored. The low concentration of CO and unburnt HC in the diesel exhaust are compensated by high concentration of NOx. Diesel engines also emit smoke particles and oxygenated HC, including aldehydes and odourproducing compounds having high nuisance value. Smoke from diesel engines comes in three different hues white smoke emitted during cold start idling and at low loads; blue smoke from the burning of lubricating oil and additives; and black smoke, a product of incomplete combustion. Black smoke, the most obvious type of vehicular air pollution, consists of irregular shaped agglomerated fine soot/particulates, the formation of which depends on injector nozzle parameter and type of combustion chamber (direct or indirect injection). Black smoke is a particular problem with diesel engines that are not well tuned, which is often the case in the developing world. [2] Impact of Fuel Quality on emissions [1] Much of the pollution control depends on the quality of the fuel (Gasoline and Diesel). So the characteristics that determine fuel quality also become important. A high Reid pressure8 in the case of gasoline engine causes a high evaporative emission while an increase in the density results in a simultaneous increase in CO and HC in the exhausts. Likewise in the case of diesel vehicles, a higher density causes higher smoke, CO and NOx emissions, while enhancing the certain number of ignition quality lowers the smoke emission. The sulphur content of diesel has been observed to have a direct bearing on the SPM and SO 2 emissions (CPCB, 1999). [10] Comparison of Diesel and CNG Run Engines The combustion of fuels release SO 2, NO x, CO and ozone. The CO is highly noxious gas that forms when there is not enough oxygen during the combustion. The CO 2 however, oxidizes very fast and forms CO 2, which though is not noxious but is one of the major contributors of greenhouse effect. This implies a reduction of CO 2 hence CO 2 emissions, can only be achieved by improving the engine efficiency or by using fuels containing lower concentration of carbon such as natural gas. The compressed natural gas (CNG) is a cleanburning alternative fuel for vehicles 10 with a significant potential for reducing harmful emissions especially fine particles. Nylund and Lawson (2000) find that diesel combustion emits 84 grams per kilometer (gms/km) of such components as compared to only 11 gms/km in CNG. The levels of greenhouse gases emitted from natural gas exhaust are 12% lower than diesel engine exhaust when the entire life cycle of the fuel is considered. It has also been found that one CNG bus achieves emission reduction equivalent to removing 8594 cars from the road. Table 2 gives the emission benefits of replacing conventional diesel with CNG in buses. TABLE II. BENEFITS OF REPLACING CONVENTIONAL DIESEL WITH Fuel CNG IN BUSES Pollution Parameter CO NOx PM Diesel 2.4 g/km 21g/km 0.38g/km CNG 0.4 g/km 8.9g/km 0.012g/km % Reduction Source: Frailey et al. (2000) as referred in World Bank (2001b:2) Diesel with sulphur content of 10 ppm (also called as clean diesel ) is environmentally viable only when it is combined with other technology such as the state of the art exhaust treatment devices like continuously regenerating particulate traps (CRTs). Incidentally the devices are also highly maintenance intensive. Apart from the fact that CNG does not contain polyaromatic hydrocarbons (PAHs), airborne toxins and SO 2, CNG run vehicles have more quiet operation, less vibrations and odour than equivalent diesel engines. However, high vehicle cost, shorter driving range, heavy fuel tank, expensive distribution and storage network and potential performance and operational problems compared to liquid fuels are some of the drawbacks of using CNG vehicle (Watt, 2001 as referred in World Bank, 2001b). [1], [8] Emissions caused by Congestion Congestion engenders a double effect. First the time cost of a vehicle kilometre rises rapidly with increased congestion. This is because the addition of a vehicle to an already crowded network increases travel time for many other passengers. Since the average speed has reduced to levels that are far below the optimal operating vehicles speed, this leads to increase in rate of emissions per kilometre thus the two effects are interrelated (Johansson, 1997). The congestion has cost nearly US$ 14 billion in terms of excess time required and gasoline 39

3 consumed to the commuters in California, in addition to substantial environmental damage 1 states that a reduction from 40 km/h to 20 km/h doubles the emissions of CO and volatile organic compounds (VOCs) for a car fitted with a catalytic converter. Since VOCs and CO are 250% higher under congested conditions than during freeflowing traffic, poor air quality is the consequence. [10], [3] III. EMISSIONS STANDARDS The first Indian emission regulations were idle emission limits which became effective in Since the year 2000, India started adopting European emission and fuel regulations for fourwheeled lightduty and for heavyduty vehicles. Indian own emission regulations still apply to two and threewheeled vehicles. The first Indian emission regulations were idle emission limits which became effective in These idle emission regulations were soon replaced by mass emission limits for both gasoline (1991) and diesel (1992) vehicles, which were gradually tightened during the 1990 s. Since the year 2000, India started adopting European emission and fuel regulations for fourwheeled lightduty and for heavyduty vehicles. Indian own emission regulations still apply to twoand threewheeled vehicles. On October 6, 2003, the National Auto Fuel Policy has been announced, which envisages a phased program for introducing Euro 2 4 emission and fuel regulations by Wheel Vehicles The implementation schedule of EU emission standards for 4wheel Vehicles in India is summarized in Table 3 TABLE III. INDIAN EMISSION STANDARDS (4WHEEL VEHICLES) Standard Reference Date Region India 2000 Euro Nationwide Bharat Stage II Euro NCR*, Mumbai, Kolkata, Chennai NCR*, 11 Cities Nationwide Bharat Stage III Euro NCR*, 11 Cities Nationwide Bharat Stage IV Euro NCR*, 11 Cities *National Capital Region (Delhi) Mumbai, Kolkata, Chennai, Bangalore, Hyderabad, Secunderabad, Ahmedabad, Pune, Surat, Kanpur and Agra. The above standards apply to all new 4wheel vehicles sold and registered in the respective regions. In addition, the National Auto Fuel Policy introduces certain emission requirements for interstate buses with routes originating or terminating in Delhi or the other 10 cities. For 2and 3 wheelers, Bharat Stage II is applicable from April 1, 2005 and Stage III standards come in force from April 1, [4] Light Duty Vehicles Emission standards for lightduty vehicles are summarized in Table 4. Ranges of emission limits refer to different categories and classes of vehicles; compare the EU lightduty vehicle emission standards page for details on the Euro 1 and later standards. When three limits are listed, they refer to vehicles category M & N1 Class I, N1 Class II, and N1 Class III, respectively. TABLE IV. EMISSION STANDARDS FOR LIGHTDUTY VEHICLES, G/KM Year Reference CO HC HC+NOx NOx PM Diesel Euro Euro Euro Euro Gasoline * Euro Euro Euro Euro * for catalytic converter fitted vehicles only in selected regions, see Table TABLE V. EMISSION STANDARDS FOR LIGHTDUTY DIESEL ENGINES, G/KWH Year Reference CO HC NOx PM Euro I * 2005 Euro II * for engines below 85 kw Gasoline vehicles must also meet an evaporative (SHED) limit of 2 g/test (effective 2000).Through the BS II (Euro II) stage, engines for use in lightduty vehicles could be alternatively emission tested using an engine dynamometer. The respective emission standards are listed in Table 5. Truck and Bus Engines Emission standards for new heavyduty engines are listed in Table 6 40

4 TABLE VI. EMISSION STANDARDS FOR DIESEL TRUCK AND BUS ENGINES, G/KWH Year Reference Test CO HC NOx PM 1992 ECE R ECE R Euro I ECE R * 2005 Euro II ECE R Euro III ESC ETC Euro IV ESC ETC * for engines below 85 kw only in selected regions, see Table 1 2 And 3Wheel Vehicles Emission standards for 2 and 3wheel vehicles are listed in the following Table 7 TABLE VII. EMISSION STANDARDS FOR 2 AND 3WHEEL VEHICLES, G/KM Year Standard CO HC HC+ NOx PM 2Wheel Gasoline Vehicles BS II BS III Wheel Gasoline Vehicles BS II BS III And 3Wheel Diesel Vehicles BS II BS III IV. EMISSION PROBLEMS Lead PhaseOut is an Environmental Priority Environmental health and risk assessment studies in various parts of the world from Asia to North Africa and Central and Eastern Europe have shown that lead was one of the most serious health threats to large populations. The major contributor to lead exposures in urban areas is typically vehicle exhaust due to the use of leaded gasoline. As traffic grows, large urban populations are suffering serious health damage unless measures are taken to reduce their exposures to lead. While other sources of lead exposure should not be ignored, focusing on the removal of lead from gasoline separately is justified because (i) the use of leaded gasoline is a universal problem; (ii) well understood technical solutions exist to this problem. Studies on health effects The epidemiological and toxicological evidence on the effects of transportrelated air pollution on health has increased substantially in recent decades. A review of this evidence indicates that transportrelated air pollution contributes to an increased risk of death, particularly from cardiopulmonary causes. It increases the risk of respiratory symptoms and diseases that are not related to allergies While only a few studies have been conducted on the effects of transportrelated air pollution on cardiovascular morbidity, they report a significant increase in the risk of myocardial infarction following exposure A few studies suggest an increased incidence of lung cancer in people with longterm exposure to transportrelated air pollution. They indicate that reducing this pollution may directly reduce acute asthma attacks in children and the related medical care. Other indicators of exposure to transport related air pollution such as distance to or residence near major roads and, partly, selfreported traffic intensity at a residence are associated with several adverse health outcomes. More studies that assess the public health benefits of various measures to improve air quality particularly through interventions that address transportrelated air pollution are needed to support policies. Traffic management is one of the instruments that can significantly reduce the exposure of residents of urban areas. In particular, urban planning may aim at integrative measures that lower emission rates, such as the promotion of highly efficient, serviceoriented and clean public transport and improvements in the flow of traffic. Several technologies show promise in lowering emission levels from conventional vehicles, and their development should be promoted, along with effective control mechanisms (such as mandatory car inspections) for eliminating gross polluters and badly maintained vehicles. Finally, alternative vehicle technologies and fuel substitutes could lead to substantial future reductions in emissions of hazardous air pollutants. [12], [7] Air Pollution Air pollutants are usually classified into suspended particulate matter (dusts, fumes, mists, and smokes); gaseous pollutants (gases and vapors); and odors. Suspended PM can be categorized according to total suspended particles: the finer fraction, PM10, which can reach the alveoli, and the most hazardous, PM2.5 (median aerodynamic diameters of less than 10.0 microns and 2.5 microns, respectively). Types of suspended PM include diesel exhaust particles; coal fly ash; wood smoke; mineral dusts, such as coal, asbestos, limestone, and cement; metal dusts and fumes; acid mists (for example, sulphuric acid); and pesticide mists. Gaseous pollutants include sulfur compounds such as SO 2 and sulfur trioxide; carbon monoxide; nitrogen compounds such as nitric oxide, NO, and ammonia; organic compounds such as hydrocarbons; volatile organic compounds; polycyclic aromatic hydrocarbons and halogen derivatives such as aldehydes; and odorous 41

5 substances. Volatile organic compounds are released from burning fuel (gasoline, oil, coal, wood, charcoal, natural gas, and so on); solvents; paints; glues; and other products commonly used at work or at home. Volatile organic compounds include such chemicals as benzene, toluene, methylene chloride, and methyl chloroform. Emissions of nitrogen oxides and hydrocarbons react with sunlight to eventually form another secondary pollutant, ozone, at ground level. Ozone at this level creates health concerns, unlike ozone in the upper atmosphere, which occurs naturally and protects life by filtering out ultraviolet radiation from the sun. [5] Sources of Outdoor Air Pollution Outdoor air pollution is caused mainly by the combustion of petroleum products or coal by motor vehicles, industry, and power stations. In some countries, the combustion of wood or agricultural waste is another major source. Pollution can also originate from industrial processes that involve dust formation (for example, from cement factories and metal smelters) or gas releases (for instance, from chemicals production). Indoor sources also contribute to outdoor air pollution, and in heavily populated areas, the contribution from indoor sources can create extremely high levels of outdoor air pollution. Motor vehicles emit PM, nitric oxide and NO 2 (together referred to as NOx) carbon monoxide, organic compounds, and lead. Lead is a gasoline additive that has been phased out in industrial countries, but some developing countries still use leaded gasoline. Mandating the use of leadfree gasoline is an important intervention in relation to health. [13] Green house effect The "greenhouse effect" often gets a bad rap because of its association with global warming, but the truth is we couldn't live without it. Life on earth depends on energy from the sun. About 30 percent of the sunlight that beams toward Earth is deflected by the outer atmosphere and scattered back into space. The rest reaches the planet's surface and is reflected upward again as a type of slowmoving energy called infrared radiation The heat caused by infrared radiation is absorbed by "greenhouse gases" such as water vapor, carbon dioxide, ozone and methane, which slows its escape from the atmosphere. Although greenhouse gases make up only about 1 percent of the Earth's atmosphere, they regulate our climate by trapping heat and holding it in a kind of warmair blanket that surrounds the planet. This phenomenon is what scientists call the "greenhouse effect. [14] Carbon Dioxide Emissions Currently, carbon dioxide accounts for more than 60 percent of the enhanced greenhouse effect caused by the increase of greenhouse gases, and the level of carbon dioxide in the atmosphere is increasing by more than 10 percent every 20 years. If emissions of carbon dioxide continue to grow at current rates, then the level of the gas in the atmosphere will likely double, or possibly even triple, from preindustrial levels during the 21st century. [15], [17] Climate Change Because of vehicle emissions different types of gases will genret. Because of these gases there were major changes in climate. Global climate change caused by human combustion of fossil fuels and the resulting emission of greenhouse gases (GHGs) is along with energy security widely viewed as a critical global issue with a range of potential effects on human health, community infrastructure, ecosystems, agriculture and economic activity. [16], [6] V. CONCLUSION Even with the present standard of vehicular emission, considerable amount of pollution is observed. Therefore vehicle improvement which produces minimum pollution is he better solution for the future of India. The general observation is described in this paper and explained how different fuel and types of vehicle create different amount of emission problem. The paper also describes different standard values for emission for different vehicles for different fuels. There are also different emission problems which can destroy or affect a human life. Due to vehicle emission many environment related problems creates therefore reducing emission will defiantly step toward better tomorrow. REFERENCES [1] Frailey et al. (2000) as referred in World Bank (2001b:2) [2] Central Pollution Control Board (1999) Parivesh: Newsletter, 6(1), June, CPCB, Ministry of Environment and Forests, Delhi. [3] Lehoczki, Z. (2000) Product charge on transport fuel in Hungary. In Economic Instruments for Environmental Management, eds J. Rietbergen McCracekn and H. Abaza, pp Earthscan, London. [4] Nylund, N.O., Lawson, A. (2000) Exhaust emissions from natural gas vehicles. International Association of natural gas Vehicles, VTT Energy, Finland. [5] Pundir, B.P. (2001), Vehicular Air Pollution in India: Recent Control Measures and Related Issues, in India Infrastructure Report 2001, Oxford University Press, Delhi. [6] Felix Creutzig and Dongquan He (2009), Climate Change Mitigation and CoBenefits. [7] Blackman, A. and Harrington, W. (2000) The use of economic incentives in developing countries: Lessons from international experience with industrial air pollution. The Journal of Environment and Development 9, 544. [8] Kathuria, V. (2004) Impact of CNG on Vehicular Pollution in Delhi a note, Transportation Research Part D, 9 (5): [9] [10] [11] [12] ons.shtml [13] [14] [15] [16] [17] 42