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Air Pollution in Delhi NCR – Need for Better Understanding of Nature of Pollutants for Exploration of Long-Time Remedial Measures

October 1, 2018 - 10:58
Air Pollution in Delhi NCR – Need for Better Understanding of Nature of Pollutants for Exploration of  Long-Time Remedial Measures


Views expressed by different agencies and individuals on ‘Delhi NCR air Pollution’ remind me of the story of nine blind men describing an elephant. Pollution is complex multidisciplinary atmospheric phenomena, caused due to natural and partly anthropogenic activities. Therefore, it is necessary for any comparative studies to generate reliable base-line data. Automobile emissions, toxic chemicals (carbon monoxide, oxides of sulfur and nitrogen), polycyclic aromatic hydrocarbons, fossil fuel burning, agricultural activities such as stubble burning, or urban construction activities or types of soil etc., contribute to the pollution. Each of the pollutants leaves behind their distinct signatures. Identification of the markers will provide information on the origin of the pollutants. Therefore, the analysis of the pollutants is likely provide leads for solutions for elimination or reduction of the pollution. The information on the nature of the constituents (known as speciation) of the polluted air will furnish possible origins and locations of the pollutants. It is may be possible to suggest appropriate remedial measures accordingly. For speciation of the pollutants excellent modern analytical techniques are available. Also, availability of several data bases make the identification (dereplication) of the pollutants comparatively easy. Depending on the nature of the pollutants, remedial methods can be suggested. Studies on pollution should be carried out in holistic mode. The constituents of polluted air are highly variable and depend on atmospheric conditions (wind speed and direction, photoperiod, moisture content, suspended particles etc.,). Therefore it is necessary to generate data in the specific locations with specific conditions. Mass spectrometry, optical spectrophotometry and chromatographic techniques can be useful for the analysis of the pollutants, both qualitatively as well as quantitatively. Inductively coupled Mass spectroscopic analysis (ICP-MS) can provide information on the elemental (inorganic) composition of the pollutants. Data from such measurements can easily distinguish between the nature of the pollutants e.g. from landfill fires or from construction activities or from stubble burning. Gas chromatography-Mass spectrometry (GC-MS) and LC- ESI MS/MSn (Electro-spay ionization mass spectrometry) analytical data can furnish information on the organic pollutants (toxins for example). It can be used for monitoring the level of pollution caused by automobile emissions or stubble burning. A critical analysis of MS spectra may also provide information on the sources of the emissions. Possibly the present controversies over ‘odd-even emissions’ vehicular restrictions can be resolved by careful analysis of the mass data quantitatively. It can also be useful for finding out the sources of origin of the pollutants. This might lead to identification of useful markers of pollutants. The optical spectroscopies like UV-VIS, IR in conjunction with LC-MS mass spectrometry may also provide information for identification of the pollutants (dereplication).

Chemical Speciation (analysis) of the pollutants: Need for R & D work for long-term remedial measures and base-line data generation.

The R&D areas which might help in the understanding of the pollution phenomena are (i) GC-MS, ICP-MS, HPLC-ESI-MS analyses, (ii) Plasmon spectrometry, which will not only give information on particulate matters but also about their molecular nature (iii) the Surface enhanced Raman Spectroscopy for speciation, finger printing and quantitative analysis of the complex mixtures of the pollutants and (iv) biological or medical impacts of the pollutants (epidemiological studies).

There has been much talk about the role of dust particles (PM 2.5 & 10) in the development of pollution. It is certainly an important issue. In this context, it would be desirable to have comparative assessments of the air quality during all the seasons such assummer seasons in places like Delhi, Punjab, Haryana and UP, where the ambient values of PM values may be very high due to dust storms compared to the places like Kerala with high rain fall. A comparative speciation of the pollutants in different geographical locations can give better understanding of pollution problems and may generate new perspective for tackling the periodic pollution phenomena. These studies may be useful for drawing long-term plans for specific pollution controls measures .

At the Amrita Vishwa Vidyapeetham, Amritapuri (Kerala), we have been engaged in the analyses of extracts of intractable complex mixtures from medicinally important plants. Analyses are carried out using multiple techniques such as conventional chemical approach, optical spectrophotoscopy in conjunction with advanced techniques such as HPLC (DAAD), GC-MS and advanced mass spectrometry. Many institutes in India such as TERI, Central Pollution Board, Centre for Science and environment, Amrita School of Biotechnology, Central Drug Research Institute etc. have adequate facilities to undertake the studies suggested above. Bhabha Atomic Research Centre has been pioneer in assessment of air qualities for last several decades. Collection of samples and statically analysis are integral part of such studies. Taking advantages of the expertise and facilities available within the country and concerted efforts in the right direction will contribute towards long-term solution to the pollution problem.

“This article is authored by Dr. Asoke Banerji , Distinguished Professor, School of Biotechnology, Amritapuri

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