2.1 ASSESSMENT TOOLS

Air Pollution has its impacts at the local as well as regional level. While atmospheric transport helps in dispersion of air borne pollutants, the impacts are often felt in distance places far from the source of emissions. The increasing concern about global warming/climate changes stems from recognition of the fact that the impacts of air pollution transcend the political boundaries.

In the field of atmospheric transport of air pollution, not much work has been done in India. A number of Indian institutions and organisations, both academic and government are doing research and collecting measurement data on air pollutants and emissions.

To improve the scientific basis for global change estimate models need to be developed. Computer modeling will be the primary tool for development of pollution and emission database. The emission and pollutant data not obtainable by the measurements will be computed based on scientific theories. Modeling will also be used to validate the measured data.

The computational models for emission of pollutants from mobile, fixed, non combustion related, domestic and agriculture related sources would have input data about:

- Type of combustion or other process;

- Type of fuel/primary source;

- Meteorological conditions.

The measurements will be ground based and air borne. There is also need to quantify these pollutants and emissions and analyse their transport and exposure. Modeling will also be used to validate the measured data. The overall effort involving development of scientific database and assessment of the impact of the pollution on health and climatic change is an enormous task and would require investment of considerable effort and technical resources. Thus a coordinated effort is needed to study this problem.

2.2 ASSESSING IMPACTS

Exposure to air pollution has become an inescapable part of urban life. Million of urban population in the SACEP region is confronted with the environmental and health problem on account of poor sanitation and discharge and lack of safe drinking water, which are further aggravated by harmful emissions caused mainly by motor vehicles, industries and domestic combustion of biomass and fossil fuels.

The use of low quality fuel, inefficient methods of energy production and use, poor condition of vehicles and traffic management are among the reasons for increasing emissions and related impacts on human health, eco-systems and economics in the region. Although air pollutants are likely to have similar adverse effects on different populations, the range of exposure, co-exposure to pollutant mixtures, nutritional status and the life styles in developing nations, suggest that the political impacts of air pollution may be even greater than those reported for the developed nations. More information is needed to assess the impacts of air pollution and to conduct systematic epidemiological studies.

No comprehensive epidemiological study has been conducted in India to show how ambient air pollution is affecting our health. Indeed such studies are possible only when there is a good national healthcare system with high public coverage and extensive pollution and weather monitoring.

A few systematic studies on the air pollution and its effects on human beings have been reported for urban centres like Mumbai (Kamat, S.R.; Godkhindi, K.D., Shah B.W.etc. "Correlation of health morbidity to air pollution levels in Mumbai city) Ahmedabad (Monograph I. National Institute of Occupation Health, Ahmedabad), Bangalore (Annual Report, 1984-85 National Institute of Occupational Health, Regional Occupation Health Centre (Southern), p. 24) and Vadodara (A report of Integrated Air Quality Surveillance Study over Vadodara Urban Development Area. National Institute of Occupational Health, Ahemdabad, 1989). A study conducted by National Institute of Occupational Health, Ahmedabad (NIOH) in 1978 as part of WHO UNEP/GEMS programme in Global Biological Monitoring showed that the blood level in teachers in three cities like Ahemdabad, Bangalore and Calcutta regional between 100-200 m g/l. The study covered out by NIOH in HEAL programme in 1993 at Mumbai showed that blood lead levels in working women range between 37-124 m g/l Lead in the daily duplicate diets (including beverages) ranges daily average 6.4-76.9 m g while lead levels in the breathing zone air (personal monitoring) range daily average 147-476 m g Pb/m³ in low exposed areas and 131-864 ng Pb/m³ in high exposure area of Mumbai.

A study conducted in Delhi indicates one out of every 10 school children in Delhi suffers from asthma that is worsening due to vehicular due to vehicular air pollution (Chhabra, S.K.; 1996. Prevalence of Bronchial Asthma in School Children of Delhi, Vallabbhai Patel Chest Institute Delhi).

  Blood lead levels in children living in metropolitan cities are alarming by high. In 41% of the blood samples taken from children living in both low and high ambient air levels located in Delhi in 1996, lead level were found to be greater than 20 microgrammes per decilitre (Kalra, V; 1998, Lead Pollution and Health concerns, paper presented in the National Conference on Health and Environment, organised by Centre for Science and Environment, New Delhi).

Recently George Foundation carried out a study of blood lead levels in approximately 22,000 samples taken in seven major Indian cities showed about 50% population (mainly children) have lead levels higher than 10 m g/dl which is suggestive of health risk, as such lead concentration could lead to adverse health effects, especially in children. No impact on health of exposed children was studied as well as no attempt was made to study the cause of such higher levels. These data do not seem to be supported with rigid Quality Assurance programme and are having certain limitations in the study results.

The recent World Bank estimates for air pollution/health risks for 36 cities in India indicated that there could be over 40,000 premature deaths with 7500 (19%) in Delhi, 5700 (14%) in Calcutta and 4500 (11%) in Mumbai due to exposure to current levels of air pollution. These premature deaths could have been avoided if the air pollution levels in these cities were brought down to the WHO Standards. These studies have shown the qualitative effects of air pollution especially on high risk population groups.

Not many studies have been undertaken till in the field of biological air pollution or of the potential biohazards such as bio-allergens. Biological contamination’s of air include fungus, viruses, bacteria, insects, vegetable, dust pollen grains, etc. Indian studies on bio-allergens have been restricted to only a few towns and cities like Aurangabad, Jaipur, Calcutta, Delhi, Bangalore, Gulbarga, Gwalior and Imphal. Studies on bio-allergens will be an important aspect of air pollution in addition to routine chemical analysis.

In India, the recognition of the magnitude of the air pollution problem is a recent phenomenon. The experience gained in western countries can at best serve as guidelines. But for the formulation of Indian air pollution control programme the epidemiological data pertinent to local conditions can only be used. This is because vast differences exist at every stage in conditions of western affluent society and Indian urban centres. In our country, the pattern and strength of sources is different. The meteorological conditions as well as building lay outs and road load conditions alongwith traffic pattern is unique and different from Western countries. Further for evaluating dose-effect relationship the most important factor "MAN" along with his social cultural set up is not comparable on equal term with Westernites due to difference in genetic make up, nutritional status and general health standards.

 There may be basically three kinds of factors that can influence biological responses. These are (i) those related to the potency of the pollutants or there chemical and physical characteristics; (ii) those related to the exposure concentrations and duration and (iii) those related to the condition of subject exposed. Although the quantum of differences in Indian condition in comparison to developed nations, for all these factors are quite high but as far as the data on the health related studies in India are concerned there is almost a total absence of data.

As systematic poisoning/toxicity and epidemiological data are not available on the health status of the population in polluted urban cities in country, there is a growing need to develop nation wide integrated programme on the effects of human health of air pollution. To design an appropriate intervention strategy, it is important to have information on both the aspects, i.e. environmental pollution load (for specific pollutants) and human health status to establish a cause effect relationship. The action plan should focus on:

- Estimation of exposure of residents/commuters/workers.

Methodology for determination of population exposure from various sources using dispersion modeling and air pollution monitoring needs to be developed. The population exposure distribution should be reliable, since it forms the basis for assessing damage to health and the cost resulting from such damages.

For standardisatipn of methodology and development of protocols the health assessment studies can be initiated in the 6 cosmopolitan cities (i.e. Delhi, Mumbai, Chennai, Calcutta, Bangalore and Hyderabad) and two metro cities (i.e. Ahmedabad and Kanpur).

Though the air pollution concentration show an increasing trend, yet the information on associated health effects is lacking. As a consequence, there is frequently little bases for decision makers to priorities alternative control strategies and policies, in deciding which pollutants need to be controlled, in what way and to what extent. There may occur a range of differing circumstances for which a rapid appraisal may be necessary. There may be an air pollution episode of widespread regional significance Such as the recent forest fires in Southeast Asia, which demands immediate, rapid assessment and response. To meet such eventualities, there is urgent need for developing methodology for Rapid Assessment of Air pollution and Health. The rapid appraisals should be conducted in a rigorous and unbiased a way as possible.

The concept of exposure is not confined solely to pollutants that produce direct health effects. Pollutants such as NO_x and SO_x can produce acid deposition (rain, snow or particles alone) by conversion through atmospheric chemistry, often far from their source, to acidic aerosols (mixture of liquid and solid particles). Acid

deposition is not a problem everywhere. Much of the Earth surface is covered with ocean, soils and vegetation that are little affected by acid deposition. Other areas, however, such as some type of crops, forests and lakes can be damaged. Whether a certain emission sources create an exposure of concern, therefore, depends on its orientation and distance from vulnerable eco-systems, local wind patterns etc. This is exactly parallel to the relationship of health damaging pollution source. The same concept applies to green house gases, e.g. methane and carbon dioxide, which indirectly affect human health through global warming.

Air pollutants such as sulphur dioxide; nitrogen dioxide and ozone are known to cause damage to crop production and forest cover. Ozone and sulphur dioxide in particular is responsible for causing reduced crop yield. In USA, yield losses of grain crops due to ozone have been estimated at 5 per cent per year. The potential for crop yield losses in Asia has been demonstrated by a study in Pakistan, where a 40 per cent reduction in rice yields has been linked to the presence of air pollutants. (Wahed A; Environmental Pollution Vol 90, No 3 pp 323-329)

The accumulation of nitrogen in eco-system has also led to damaging changes in the health and bio diversity of plant communities and to the fertilisation of coastal and marine environment. Nitrogen deposition can acidify soil, fertiliser, sensitive plant communities and lead to imbalances that may destabilise the ecosystems.

Considering that hardly any data is available on the impacts of air pollution on aquatic, ecosystems, soils, ground waters, malarial, livestock and visibility in the country. It is important to initiate studies in this area. The studies should aim at assessing quantum of the impacts of air pollution and also the threshold for pollution damages at the same time looking at the needs for redefining the air quality standards, as the air quality standards in India are primarily aimed at reducing the direct impact of air pollution on health and to a lesser extent architectural heritage. The study should cover methodology standardisation aspects also.

2.3 ASSESSING PREVENTION/ABATEMENT OPTIONS

The abatement option can be divided into following groups:

. Improving fuel quality

Unleaded gasoline (0.013 gm load/l) has been introduced throughout the country from February 1, 2000. The introduction of unleaded gasoline will effectively reduce lead emissions. Reduction in Benzene concentration in gasoline will reduce emission of VOCs.

. Improvement in quality of diesel as regard to the increase in octane number and reduction in sulphur content though would not result in a proportional decline in SO₂ emissions, but would also lead to a fall in PM₁₀ emissions.

. Adoption of green fuels

CNG used as a fuel substitute can effectively reduce PM₁₀ emissions.

. Adoption of clean vehicle emission standards

The adoption of strict emission standards makes it mandatory for the vehicle manufacturers to use state-of-the-art technology. As the emission requirements are met by adjusting the motor design, the fuel must be of a much better quality than is presently available. This will help in reducing emissions of PM₁₀, VOC and CO.

. Implementation of an inspection and maintenance scheme

Maladjusted fuel injection systems or carburetors and worm out motor parts present a threat to traffic safety, increase fuel consumption and thus costs and lead to traffic emissions. The annual inspection and maintenance of vehicles will probably result in substantial reduction of PM₁₀, VOC and CO emissions.

The success of the abatement and control options will be reflected in the air quality data captured by the monitoring stations especially the real time monitoring stations. The reduction in the concentration of pollutants can be correlated to the emission sources using various dispersion models available and even by using the finger print technique.

2.4 REPORTING

Time Frame is to be fixed for implementation of each important of the Action Plan, identifying the agency responsible and the impact the action would have on abatement/control of air pollution. Regular assessment of the atmospheric air pollution is required to judge the success of the mitigation measures undertaken, including their impacts and also to plan the future course of action. Yearly report on the comprehensive pattern of air pollution in the country can be prepared highlighting the air quality trend, impacts of air pollution observed, assessment of the abatement/control option implemented and the need for additional measures if any required.