Introduction

         It is a known fact that there is no easy method to combat toxic air. Air is polluted by physical, chemical and biological particulates. These particulates can easily reach our respiratory system and in turn the blood circulation. Toxic air can affect anybody and there is no privilege in reaching people. When studying the pollutants, the Particulate Matter below the size range of 10µm (PM₁₀) and below 2.5µm (PM_2.5) alone are given importance among physical pollutant. Chemical pollutants are mostly considered as a local phenomenon occurring due to Industrial accidents, Among them emphasis has been given to monitor CO, CO₂, O,. NO₂, NH₃, SO₂ and Benzene. The biopollutants include viruses, bacteria, fungal spore-s, pollen grains, fern spores. insect wings, protein and amino acids of biological origin. However the impact of biological pollutants was not given much importance in India until it becomes epidemic or pandemic in nature. As such no biological parameters are monitored by Pollution Control Boards (PCBs) In India.

         Chennai is one among the four major cities in India with the population of nearly 11 million. Due to rapid industrialization and urbanization, the city face many problems due to pollution and among them air pollution has emerged as a concern lately. In Chennai, the air pollution due to firing crackers during Diwall and in the month of January due to the celebration of Bhogl are general phenomenon. However, formation of haze during the month of November in 2019 is of great shock for the residents of Chennai and the authors too experienced this new phenomenon. Thus, the article provides inputs on the occurrence of haze, their physical character, chemical nature and their impact on the environment. Authors aLso have proposed a new term, i.e. “BIOSOOT” as the soot generated from burning of biological materials (silages) ¡n fon’nabon of haze.

Haze In Chennal

         On Monday November 4, 2019 people of Chennai experienced an atmosphere filled with haze This situation lasted until 9^th of November 2019 as a short speLl of rain on the following day cleared the atmosphere and this event was not a routine for the city. Answers were needed as of to why there was haze and what was the reason behind it? It is a known fact that New Delhi is commonly prone to haze due to the pollutants arising by burning of silages in adjacent states. But, the Chennai city has never experienced the haze as similar to that of Delhi. The Tamil Nadu Pollution Control Board stated that this is due to local activities, Le. dust, vehicular pollution and absence of air current Irom the seashore which resulted in haze, The meteorological department reported that, the haze is due to local pollution and had no similar reasons with the pollution in Delhi (The Hindu, 5^th November 2019). However, few Environmental activistsdaim, that the haze might have reached Chennai from New Delhi where silages are burnt, Few claim that due to Kyarr and Maha. the cyclones which prevailed in the Arabian Sea and Bulbul in the Bay of Bengal. resulted in air current that brought the haze from New Delhi towards South of the Nation. Further, the haze was also reported in Sri Lanka during this period which was confirmed by the statement of Mr. SarathPadmasin, Senior Scientist. National Building Research Organization, Sri Lanka, claiming that the pollutants from India are being carried to Sn Lanka (The Hindu, 7^th November 2019). Colombo recorded more than 150mg of PM_2.5. on 6^th of November an uncharacteristically high. With these controversies, the present review provides some Inputs In this discussion.

Constituents of Haze

        Haze Is defined as a phenomenon which obscure the clarity of the sky due lo the presence of dust, vehicular emission, smoke and other particulales in the atmosphere. The dust generated due to fine sand or dry soil become airborne and serve as a physical irritant The vehicular emission is found to contain mainly of carbon along with few organic compounds arising due to partly combusted fuels. Smoke emanates mostly due to combustion of materials. Generally they are termed as either Carbon Black or Black Carbon. However. when the haze is developed due to burning of silages then the composition Is under question. Thus, the authors want to propose a new term as Biosoot. Biosoot Is defined as the smoke or soot generated when burning the biomaterials which may either be of plants or animals origin.

Exposure to Haze

         Due to different composition and contribution by many agents the air becomes toxic. The particulates suspended in air is generally studied with two major size distribution. Particulate matter below the size range of 10µm (PM₁₀) and above the size range of 2.5µm (PM_2.5). However, the size distribution of particulate matter in haze in this case is under question. The size range of the biosoot generated by combustion of plant material was studied by the authors and they found that mayor part of the particulates is between the size ranges of 200nm - 600nm. Thus, they have the ability to penetrate deep in to the lungs (Prakash et al.. 2019).

Impact of Haze

         The haze when in contact with skin may cause skin initation. Further, when they are inhaled may worsen respiratory systems due to the chemical constituent of the particles present in haze. Authors have studied, the chemical composition of hiosoot belonging to different species of plants using Fourier Transform mfra-Red (FTIR( Spectroscopy and found that the chemical composition of individual plants are different.

         It is noticed that among the communicable diseases, Acure respiratory infection (ARI) accounted for 69.47% morbidity leading to nearly 27% of mortality. When you breathe in polluted air. particulates as pollutants penetrate and Inflame the linings of respiratory system Including bronchial tubes and lungs (The Hindu. 6^th November 2019). There was an increase in cases reporting Chronic Obstructive Pulmonary Disease (COPD) during the haze season in Chennai (The Hindu, 6^th November 2019). These nanoparticles can easily reach the alveolar region of lungs, thus serving as both irritant and obstructing agent.

         The major concern is the size of the particles which causes health impacts. i.e. bronchitis, asthma, chronic cough, sinusitis. pharyngitis and cancer, The particles of less than 1µm have an ability to enter blood stream and this can even pass through the blood brain barrier lithe particles reach renal system it may result in problem associated with kidney, reaching the neurotic system may result in other neurotic diseases like Parkinson’s and Alzheimer’s. The risk to pregnant women and baby is also reported dueto exposure to toxic air.

         The impact of haze on plants found to hinder the penetration of sunlight thus reducing the efficiency of photosynthesis in turn affecting other metabolic activities of plants. Long term prevalence of haze reduces exposure to light may have very high impact on Food Chain.

Conclusion arid Recommendations

         The partides suspended in haze vary in size and chemical composition. Thus it is important to study the impact of these particles using Laser Particle Analyzer (LPA) for size distribution and FTIR & Gas Chromatography for chemical composition. Stake holders such as Ministry of Environment. Forestry and Climate change, Centrai Pollution Control Board (CPCB) and other State Pollution Control Boards should increase facilities across the nation to study the same.

         It Is known that World Health Organization (WHO) have sale standards for PMIO and PM2.& However, after extensive studies on particulate matter of sub micro particles, safe standard for the same has to be brought. This specifically suits for biosoot as their size ranges well below 0.6µm. Further, as biosoot are of biological origin, this needs to be included as one among the major biocomponent along with other components in studying hioaeroso!s by aerobiologists.

References

Prakash, N. U.Snpriya.N.. Gowtham. K.. Suresh, S., Sarnpathkumar.B and Bhuvaneswarl, 5. (2019). A study on the impact of fire crackers on airborne microflora during diwali. Heliyon. 5 (8): e02202.

Special Correspondent (2019). “Is Delhi’s polluted air causing smog In Chennal?” The Hindu Newspaper.Chennai ed. 05 November20 19.

Special Correspondent (2019). “Activists call for city’s Inclusion In National Clean Air Programme”. The Hindu Newspaper. Chennai ed. 06 November 2019.