Low hangs the polluted air

Enveloped by a thick layer of smog for days, Delhi has had its air pollution levels skyrocket, scream out a warning loud and clear. But is it loud enough to alert Bengaluru, trapped in massive, unprecedented vehicular pollution? Just round the corner, the winter will only make it worse, warn the city's pollution watchers in all graveness.

Fumes billowing out of an estimated 67 lakh vehicles contribute a staggering 42% of the pollutants in the Bengaluru air. The low temperature, low pressure, high mist wintry air will keep these pollutants trapped at a level much lower than in summer. Be prepared, this 'inversion effect' will prevail till January end or even beyond.

Winter risks

Here's a scientific explanation from the Karnataka State Pollution Control Board (KSPCB): The mixing height (layer between the earth's surface and the point where the free atmosphere starts) is generally about 1 km. During winter, this is halved, increasing the concentration of pollutants.

Beyond the toxic vehicular emissions, road dust contributes 20% of the pollutants. The constant motion of vehicles keeps these dust particles suspended in low air. Directly exposed to these micro and nano-sized pollutants are motorcyclists and pedestrians in their teeming lakhs.

Industrial pollutants

Industrial pollutants and construction activities contribute 14% each, while DG sets operated by commercial establishments and apartments make up another 7% of the pollutants. Only three per cent of the pollutants are from domestic households, as KSPCB data indicates. In all, 54.4 tons of dust particles are generated from different sources, every single day.

But what is of immediate concern is the alarming rise in the proportion of Particulate Matter 2.5 (PM 2.5) in the air. These are tiny, fine particles or droplets in the air that are two and half microns or less in width. Particles of this size can travel deep into the human respiratory tract, reaching the lungs.

Medical research has clearly established that exposure to these fine particle pollutants can cause eye, nose, throat and lung irritation; coughing, sneezing, runny nose and shortness of breath. It can also affect lung function and worsen medical conditions such as asthma and heart disease.

PM 2.5 particles

So, where do Bengaluru stand in PM 2.5? A KSPCB official says the levels have far exceeded the permissible limit of 40.0 micrograms / cubic metre at many traffic junctions. At the Central Silk Board, where vehicles are stuck in jams for hours, the PM 2.5 level stands at 58.0. At TERI, Dolur, it is only marginally better at 55.4 micrograms/cubic metres.

To tide over the capital crisis, the Delhi government had decided to reintroduce its controversial odd-even rule, before withdrawing it on reservations raised by the National Greens Tribunal (NGT). But the rule had the state government here thinking. Home Minister Ramalinga Reddy even declared that Bengaluru too will try out the odd-even vehicle rationing scheme if it works in Delhi.

But experts warn that unless some ways are found to reduce the explosive vehicle numbers in Bengaluru, the pollution levels will continue to soar. Reddy talked about widening roads to decongest roads. How will that help, wonder mobility analysts. The wider the roads, the more you incentivize vehicle-owners.

Continuous air quality monitoring

To keep track of the pollution, the Delhi government has now set up 43 continuous ambient air quality monitoring stations. But KSPCB has none of these. Instead, it relies on 21 air quality monitoring centres. For real-time data on Air Quality Index, the only data available is from the Central Pollution Control Board (CPCB) portal (www.cpcb.nic.in), monitored from five centres.

But this will change, informs KSPCB chairman, Lakshman. The Board has decided to switch from manual ambient air quality monitoring stations to continuous ambient air quality monitoring systems (CAAQMS). Analyzers will be installed to capture real-time data of the pollutants in a phased manner. "All the monitored data on ambient air quality of respective places will be connected to the CPCB server and Board server for the use of general public."

These CAAQMS are proposed to be installed at Central Silk Board, NIMHANS, Veterinary College, Kavika on Mysuru Road, Jayanagar 5th Block. Trial run is currently under progress.

To guage the impact of vehicular emission on the ambient air quality, the Board has also procured 12 mobile vans. These are equipped with smoke density meters for diesel vehicles and gas analysers to measure carbon monoxide and hydrocarbons for petrol vehicles. Six of these vans are now in Bengaluru city and the rest in different parts of the State.

Weather factor

The severity of weather conditions has a direct impact on pollution. The Karnataka State Natural Disaster Monitoring Centre (KSNDMC) director Srinivasa Reddy says Delhi and Bengaluru might seem different climatically now. But if conditions change during winter, the symptoms of extreme pollution could change here too, he points out.