For days now the forests ofUttarakhandhave been on fire, turning the air over the pristine hill state lethal. Levels ofblack carbon, or soot, have shot up six times while that of ozone has trebled both going straight from safe levels to dangerously toxic ones within perhaps a week.
levels had gone from about 1,000-2,000 microgram per cubic metre last month, before thefiresstarted, to 10,000-12,000 microgram per cubic metre of air.
Theconcentrationof ozone, which used to be around 40-45 parts per billion then, has risen to 110-115 parts per billion now. The safe threshold for black carbon in the air is 3,000-4,000 microgram per cubic metre, while that of ozone is 40-50 parts per billion with an hourly range of 80 and an eight-hour Average range of 60. High black carbon and ozone in the air can cause complications from chest pain to coughing, irritation and, on prolonged exposure, damage the heart and lungs.