Explained: As Diwali approaches, where do cleaner ‘green crackers’ stand?https://indianexpress.com/article/explained/as-diwali-approaches-where-do-cleaner-green-crackers-stand-6080965/

Explained: As Diwali approaches, where do cleaner ‘green crackers’ stand?

The “green firecrackers” are supposed to have a changed composition of chemicals, and emit 30% less particulate matter when burned as compared to traditional firecrackers.

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Green firecrackers on sale near Jama Masjid in Delhi last week. (Express Photo by Shivam Patel)

With less than a week left for Diwali, there is no clarity on the types of firecrackers that individuals and families conscious of reducing their pollution footprint should buy. Air quality, especially in North India, meanwhile continues to get steadily worse.

In October 2018, the Supreme Court had ruled that only “green firecrackers” having low emission and permissible sound limits were to be sold and used. It had also fixed a timeslot for fireworks — between 8 pm and 10 pm on Diwali, and between 11.45 pm and 12.30 am on Christmas Eve and New Year.

This decision followed a complete ban on the sale of firecrackers in Delhi by the Supreme Court in November 2016 after the national capital witnessed a severe episode of smog, described by the Centre for Science and Environment as the worst in 17 years.

This year, on October 5, in a bid to combat air pollution, the Union Ministry of Science and Technology launched environment-friendly firecrackers developed by the Council of Scientific and Industrial Research (CSIR) laboratories.

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CSIR-NEERI (CSIR-National Environmental Engineering Research Institute) states that it has been working since January 2018 to develop new and improved formulations for reducing emissions from fireworks.

“CSIR-NEERI developed new formulations for reduced emission light and sound emitting crackers (SWAS, SAFAL, STAR) with 30% reduction in particulate matter using Potassium Nitrate (KNO3) as oxidant”.

In other words, the “green firecrackers” are supposed to have a changed composition of chemicals, and emit 30% less particulate matter when burned as compared to traditional firecrackers.

What is particulate matter?

Particulate matter is a mixture of solid particles and liquid droplets suspended in the air. These include PM10, which are particles with a diameter equal to or less than 10 micrometres, and PM2.5 that are of diameter equal to or less than 2.5 micrometres.

Numerous studies have linked particulate pollution exposure to many health problems, including premature death in people with heart or lung diseases. They can also settle on ground or water and, depending upon their chemical composition, may have an adverse impact on them.

Could conventional crackers have been tweaked to obtain similar results?

They could, and they have been modified. Apart from ‘green crackers’, there are other formulations based on new oxidisers, fuel and additives — singly or in combination — which have managed to reduce PM10 and PM2.5 emissions by more than 50%. These are being tested at present, and are showing encouraging results.

Other than these new formulations, CSIR-NEERI also teamed up with fireworks manufacturers and “examined and assessed the possibilities of improvements in conventional formulations based on barium nitrate to meet the stipulated norms of green crackers”. This effort too has produced some results. For instance, there is a light-emitting cracker that has partially substituted barium nitrate with potassium nitrate and strontium nitrate.

How do ‘green crackers’ work?

Dr Sadhana Rayalu, chief scientist and head of NEERI’s Environment Materials Division (EMD), said the firecrackers use a proprietary additive that acts as a dust suppressant. She added, “The usage of chemicals is less in green crackers. The total quantity is being maintained by using CSIR proprietary additive… which on fragmentation releases dust suppressants.”

Some of the ‘green crackers’ have also replaced barium nitrate as an oxidiser for combustion. Barium nitrate hurts health when inhaled, causing irritation in the nose, throat and lungs. High exposure to barium nitrate can also cause nausea and irregular heartbeat.

Among the new firecrackers developed are environment-friendly versions of traditional anar, chakri, sparklers, and other light-sound emitting firecrackers. According to NEERI, these exploit the exothermic heat of materials such as zeolite, clay and silica gel for burning, and also match the performance of commercial firecrackers in terms of sound.

How can a ‘green cracker’ be identified?

Union Minister Dr Harsh Vardhan has said a Quick Response (QR) code will be put on the firecrackers to differentiate them from conventional ones. He has also said the cost of these firecrackers would be the same as conventional ones, and that they are already available in the market.

How are ‘green crackers’ produced?

Under the current framework, the composition of firecrackers is disclosed to manufacturers after signing of a Memorandum of Understanding and a non-disclosure agreement. Following this, manufacturers have to apply to the Petroleum and Explosives Safety Organisation (PESO) for authorisation.

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The samples thus produced are submitted to CSIR for emission testing. Nearly 165 fireworks manufacturers had been roped in for production, and around 65 more were in the process of coming on board as of October 5.

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