As per the findings of researchers at the Chest Research Foundation (CRF) and Pune University, a snake tablet burns out in only 12 seconds, but produces 64,500 mcg/m3 of PM2.5 in that time, the effects of which last for three minutes. The permissible limit of PM2.5 is just 50 mcg/m3. Particles less than 2.5 microns in diameter can reach deeper portions of the lung, causing more damage.

Snake tablets were followed by ladis (strings of 1,000 crackers), pulpuls (a kind of colourfulfuljhadis), fuljhadis, chakris and anaars in the level of pollutants generated.

It is perhaps the first time that levels of PM2.5 between different firecrackers have been measured and compared, Dr Sundeep Salvi, the director of the CRF, and the main author of the study, said. The findings were presented in September this year at the European Respiratory Society.

“Our aim was to find out which firework used during Diwali produces the most amount of particulate matter air pollution. The experiments were done last year in November-December,” said Salvi.

Dr SnehaLimaye, CRF senior scientist who supervised the study, said that if it was known which were the most harmful fireworks in terms of PM2.5, people could be advised to avoid burning them. Children generally burn the fuljhadi, pulpul and snake tablet barely a foot or two away from them, and end up inhaling a large amount of smoke particles.

The researches found that after a snake tablet, ladis with 1,000 crackers created the most harm. These burn for 48 seconds, produce 38,540 mcg/m3 of PM2.5 at their peak, and the pollutants last for six minutes. Of the six popular firecrackers, anaar produced the least pollution.

“We do not know why anaar produces the lowest levels, but it could be because the levels of PM2.5 were measured at a height of 3 feet and a distance of 6 feet (from where one generally watches a lit anaar)… Or there could be better combustion of the firepowder in the anaar than other fireworks,” Salvi said.

During the experiment, the six firecrackers were burnt five times each, and individually, in an area simulating the front of a house. They were set off at a distance one would normally maintain. For example, the fuljhadi was lit around 1 feet away, and the ladi and anaar at a distance of 6 feet.

Sufficient time was given after the firecrackers had been lit to measure how long it took for the levels of PM2.5 to subside.

Researchers also pointed out that while in their experiment they burnt the crackers individually, on Diwali day,

there would be many going off simultaneously, causing PM2.5 to reach extremely high levels.

The PM2.5 levels were measured using Thermo PDR 1200, USA, a light-scattering photometer that counts the number of particles and converts them into mass, which are then expressed as mcg/m3. The inbuilt data logger recorded minute-by-minute levels of PM2.5.

Apart from particulate matter, even gaseous pollution is harmful for lungs, eyes, nose and heart.