Smart yardsticks show CP air is more toxic than you know

NEW DELHI: The air you are breathing on Delhi roads may be much more toxic than you realise. The data accessed by TOI from New Delhi Municipal Council has revealed that in November and December, the average AQI at three points in Connaught Place was in ‘severe plus’ category.

While most of the 18 monitoring points, which have smart poles with sensors to take the pollution readings, have a ‘severe’ air quality index (AQI) at 400-500, three points — Pole no. 17 Inner Circle, BKS Marg Near Capital Point and Middle Circle opposite PVR Plaza — have recorded an average of 536, 623 and 587, respectively.

Places where average AQI for November and December were in ‘severe’ levels are Pole no. 100 KG Marg (454), Pole no. 21 near Madras Hotel (420.9), near Shop no. 8, Janpath Mini Market (402.8), BKS Marg near Shivaji Stadium Metro Station (414.7) and Arunachal Building near Barakhamba Road (433), among others. Jantar Mantar, YWCA, Palika Bhawan and Barakhamba, among others, have been under ‘very poor’ levels. However, there were no locations below that.

According to a senior NDMC official, 18 of these smart poles have functional air quality monitoring sensors for the past couple of months, while 14 more would start monitoring soon. The sensors can measure PM10, PM2.5, NO2, SO2, CO, temperature and humidity, among others, and send the live feeds to the NDMC 311 app.

Though CPCB’s measures AQI on a scale of 0-500, experts said it was possible for it to touch such high levels, especially at spots so close to “source of pollution”. Usually pollution monitoring stations are located at a considerable distance from roads with high vehicular traffic. CP sees a daily footfall of over 1 lakh vehicles.

Anumita Roychowdhury, executive director at the Delhi-based think tank Centre for Science and Environment (CSE), said these monitoring points show the exposure levels of Delhiites on roads, which is much more than the daily AQI bulletin.

“Though the sensor-based ones are not often directly comparable to the regulatory monitors, in this case, as it is road side hotspot monitoring, these are actually capturing the source. Connaught Place has a high traffic impact. This road-side, curb-side monitoring is capturing the direct impact of traffic pollution and bringing out how high our exposure to it is,” Roychowdhury said.

The smart poles are 12m tall and the sensors are located on the top. Does that in any way impact the readings?

According to a Delhi Pollution Control Committee official, the sample collection height is usually 3-20m. “The DPCC stations’ collection height is 4.5-5m. However, in Delhi, till 10-12m, the air quality remains the same because of the lack of dispersion,” he explained.