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PM2.5

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Bangalore

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air pollution

Namma Metro

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Bengaluru

BM went across the city to measure the quality of air Bengalureans inhale as they go about their day. The results are in: if you’re commuting in the city, the Metro is your safest betBengalureans, whenever you can, take the Metro – it might just save your lungs.To give you an idea of the toxic air you breathe every day, BM reporter Kumaran P took a test drive across the city, carrying the Sidepak AM250 Personal Aerosol Monitor with him, which takes a live, real-time measurement every one second. This, to check the quality of air an average Bengalurean breathes as he/ she goes to work, takes a bike ride, a bus or an auto, has lunch, has a cup of tea at the street corner, and so on.We measured the level of, (smaller than 2.5 microns – 30 times smaller than the diameter of a strand of hair – that go through the body’s defence mechanisms such as nasal hair and mucous lining, enter our lungs, pass into our bloodstream and reach vital organs), among the most dangerous of pollutants. The results are in – when you’re commuting, the air in the Metro is closest to the safe level (between 39-43 µg/m³; the Central Pollution Control Board national standard is 60 µg/m³).This, afterMirror reported on the city’s shockingly high PM2.5 levels on Friday – a maximum of 1,283 µg/m³ (personal exposure) at Manyata Tech Park at 6.05pm, while the maximum ambient PM2.5 level in New Delhi at 4pm was 437 µg/m³.At 1.30 pm, I started from JP Nagar (Bannerghatta Road) for Jayadeva Junction, on a bike. At 1.40pm, when I stood at the Jayadeva flyover junction, the meter reading shot up, going from 60 μg/m³ (0.060 mg/m³) to a high of 336 μg/m³ (0.336 mg/m³) in just 10 minutes – the spike presumably owing to the Metro construction and the passage of heavy vehicles.I started riding towards Dairy Circle junction, which is once again under heavy Metro construction. The readings shot up from 90 μg/m³ (0.090 mg/m³) to 204 μg/m³ (0.204 mg/m³). I expected the reading to come down when I approached the trees near the underpass, but to my surprise that is when the meter started showing 204 μg/m³, proving what BM said in its report on Thursday (‘Hedge Fund’) about hedges offering better protection against PM2.5 than trees.Next, I found myself trailing a two-stroke auto – which was emitting smoke like a chimney – towards Johnson Market on Hosur road. Almost as if on cue, the meter started vibrating, flashing red, and showed an outrageous reading of 924 μg/m³.The numbers started going down as I travelled from Johnson Market to Trinity Circle, but always stayed above 60 μg/m³.On Platform 1 of Trinity Metro station, the reading was 63 μg/m³. I boarded the train to Cubbon Park at 2.39pm. Inside, the reading immediately dipped to between 39 μg/m³ and 43 μg/m³ – the least I recorded on Saturday.When I alighted at Cubbon Park Metro station to take the return train towards MG road, the reading changed to 62 μg/m³.Yogesh Ranganath, CEO, Clean Air Platform (CAP), a collaborative platform to improve air quality in the city, accompanied me throughout my 20km journey over three hours. He said: “The underground metro stations in London usually record high levels of, but surprisingly,underground station is reporting lower levels of PM2.5. This could be because they have a good air ventilation system in place. I guess a Metro ride is the safest.”I alighted at MG Road Metro station onto Church Street, where the readings varied between 68 μg/m³ to 72 μg/m³. I spent some time walking across the street but the changes in the recordings weren’t significant.At 3.08pm I walked towards the Cauvery Emporium junction, MG Road, and stood right in the middle of the signal to record the reading. The readings stayed between 68 μg/m³ to 77 μg/m³, until the signal turned green and the vehicles started moving, after which the reading shot up to a maximum of 104 μg/m³, when a BMTC bus came by.Next, I took an auto ride from MG road to Shivajinagar at 3.15pm. The readings varied between 87 μg/m³ to 97 μg/m³ throughout the ride. When I got off near Shivajinagar bus stand, the reading spiked to 102 μg/m³.After a light meal, I took a bus back to Trinity Circle, and the reading went up immediately, the maximum being 216 μg/m³.At 4.28pm, I decided to end my test drive with a cup of tea at the street corner. And that set off the monitor, showing me what I get with my chai every day – a little sugar and 551 μg/m³ PM2.5 levels. The machine went red, as did my face.Clearly, the air we breathe is making us – paradoxically – breathless.Out of 12 regulated pollutants, PM 10 and 2.5, NOx and Ozone are the ones which have the worst impact on health. In ‘Harvard six Cities Study’, published in 1996, it was revealed that PM2.5 was one of the causative factors of human non-accidental death. This study, reported in the research paper ‘The impact of PM2.5 on the human respiratory system’ (2016), also found that PM2.5 was positively related to daily morality of humans, and there was a linear relationship between non-accidental death and PM2.5.The solution, then, lies in urgent intervention. Wear an N95 mask on the street; report polluting vehicles when you see them; get your own vehicle checked and certified regularly; segregate your garbage; report leaf burning in your area and take the initiative to help the authorities compost instead; keep an eye on pollution levels like you do on temperature and plan activities around it; buy recycled products to help create a market for products which re-use waste, which otherwise would have been burnt; segregate your garbage and try to compost organic waste locally at home; talk to your workplace authorities about adopting environmentally friendly policies at every level possible.is known as ‘Garden City’, so let’s try and keep that moniker alive.— With inputs by Piyush Ranjan