Important parameters affecting quality of emission from automobiles are vehicular technology, fuel type and quality, inspection and maintenance of in-use vehicles, and road and traffic conditions. The quality also varies with the type of engine, and load and speed at which they run.
Prescribed standards are supposed to take care of all these possibilities. Different automobile engines emit the maximum amount of specified pollutants at varying driving conditions that may be different from corresponding test conditions defined in corresponding driving cycles.
Further, the intake air, having significant concentrations of the pollutants and relative deficiency of oxygen particularly in highly polluted urban areas, may also yield test results showing even non- polluting vehicles as polluting.
Image Source: cdn.yourarticlelibrary.com
| Pollutants | Effects on Human Health | Effects on the Natural Environment |
| Carbon monoxide | Can affect the cardio-vascular system, exacer-bating cardiovascular disease symptoms, particularly angina; may also particularly affect foetuses, sickle cell anaemics and young children. Can affect the central nervous system, impairing physical coordination, vision and judgement, creating nausea and headaches, reducing worker productivity and increasing personal discomfort. | |
| Nitrogen oxides (NOx) | Nitrogen dioxide (NO2) can affect the respiratory system. Nitrogen monoxide (NO) and nitrogen dioxide (NO2), where they play a part in photochemical some formation, may contribute indirectly to increased susceptibility to infections, pulmonary disease, impairment of lung function and eye, nose and thread irritations. | NO and NO2 can contribute significantly to acid deposition damaging aquatic ecosystems and other ecosystems such as forests NOx can also have a fertilising effect on forests. |
| Sulphur oxides (SO2) | Sulphur dioxide (SO2) can affect lung function. | Sulphur oxides can contribute significantly to acid deposition impairing aquatic and forest ecosystems. Sulphates can affect the perception of the environment by reducing visibility even at low concentrations. |
| Particulate matter (SPM and RPM) | Fine particulate matter may be toxi in itself or may carry toxic (including carcinogenic) trace substance, and can alter the immune system. Fine particulate can penetrate deep into the respiratory system irritating lung tissue and causing long-term disorders. | Fine particulate can significantly reduce visibility. High dust and soot levels are associated with a general perception of dirtiness of the environment. |
| Lead | Can cause brain damage, encephalopathy in children resulting in lower IQ, deathy, hyperactivity and reduced ability to concentrate. |
Automobile traffic is a dominant source of atmospheric pollution in urban areas all over the globe. It causes various physiological problems to the inhabitants. Therefore, perceptible concern for adverse environmental impact due to increase in automobile traffic aroused in early 1980’s even in a developing country like India.
In developed countries like USA, UK, Australia and Canada, the awakening, about the possible environmental degradation due to automotive traffic, could arise during 1960’s itself. Issues related to human environment were raised in 1972, at Stockholm.
In 1992, the representatives of over 150 countries met in Rio-de-Janeiro in Brazil to attend Earth Summit, the United Nations Conference on Environment and Development, which flashed out the concept of Sustainable Development in Agenda-21. Then, in August 2002, in Johannesburg, during the World Summit on Sustainable Development, the concern for environment was reiterated.
In India, judiciary has also played a very positive and action oriented role to curb the growing problem of air pollution in metropolitan cities. Article-48 of the Constitution of India directs the state to endeavour to protect and improve the environment.
ADVERTISEMENTS:
In 1978, the judiciary added a new climax by recognising the fundamental right to live in a clean environment and to have environmental education and information. Judiciary has also evolved the concept of absolute liability in case of environmental pollution.
There are about 30 major enactments related to the protection of environment, which are now being administered by the Central and State Governments in India.
The Air (Prevention and Control of Pollution) Act, 1981, is one of them. The Government of India has enacted the Environment (Protection) Act, 1986, to provide integrated approach towards environmental issues in the country and also to plug loopholes in the existing acts.
Urban air environment has been receiving influxes of various pollutants from automobile exhaust. Consequently, it is deteriorated to such an extent that its adverse physiological effects on the health of exposed population have become glaringly visible.
ADVERTISEMENTS:
To curb the growing menace of automobile exhaust pollution, a series of more and more stringent standards, specifying the limits on various pollutants like carbon monoxide, hydrocarbons, nitrogen oxides and Particulate Matter (PM), have evolved with the passage of time.
Implementation of these upgraded and stringent standards has led to significant reduction in the concentration of these pollutants in the automobile exhaust and consequently so in urban atmosphere. However, some aspects of the standardization require serious review to achieve further improvements in urban air quality.