It will be primarily because of vehicle exhaust, construction dust, and on-road dust in the city

The city’s increasing reliance on private modes of transport may lead to an increase in particulate matter pollution by more than 70% by 2030, states a study that has a dire prognosis for air pollution in Bengaluru.

According to the study by Urbanemissions.info along with researchers from the Center for Study of Science, Technology and Policy (CSTEP), the estimated PM10 (that is, particulate matter of less than 10 microns in size) pollution may increase by 74% by 2030, led primarily by vehicle exhaust, construction dust, and on-road dust.

Researchers established an urban emission inventory for Greater Bengaluru that covered sources such as transport (over 70 lakh vehicles currently), diesel generator sets, industries, brick kilns (over 1 billion bricks are produced by over 1,000 kilns around the city yearly), urban road dust, and open waste burning, among others. For 2015, the city emitted an estimated 31,300 tonnes of PM2.5 and 67,100 tonnes of PM10, states the study published recently in the journal, Atmospheric Pollution Research.

The city’s immense growth, particularly in vehicles and construction activity that produces copious amount of dust, is reflected in the increase in air pollution in the past few years. In 2010, the Central Pollution Control Board’s (CPCB’s) emissions inventory (for just 634 sq. km. of the city) had projected that PM10 levels would grow by 100% by 2017 from the levels they had tabulated. However, the CSTEP’s study (which covered 4,300 sq. km) finds that the rise was a staggering 300%.

“While we have covered a larger area in our study, even in the areas taken up by the CPCB there is a considerable increase in pollution. The immense increase in construction activity and vehicles was beyond their expectations,” said Sarath Guttikunda, director, Urban Emissions, who is the lead author of the study. “For now, Bengaluru’s air may be cleaner than other major metros, but the increases in the future should be a call to act now,” he said.

Prognosis for 2030

To estimate the emissions in 2030, researchers used a chemical transport model, which inculcates various factors, including implementation of infrastructure projects listed in the 2031 Bangalore Development Authority’s (BDA) master plan (whose draft was released last year) as well as better fuel quality and lower emission cars. Air pollution in the city, however, will continue to rise perceptibly: for, PM2.5, the increase could be as high as 54%, PM10 will see a 70% increase, while volatile organic compounds will see a 133% increase.

Referring to the master plan, the study notes that the share of public transport and non-motorised transport systems (cycling and walking) will fall from 62% of total trips undertaken in the city currently to just 48% by 2031. Instead, trips by private motor vehicles could correspondingly rise. Consequently, average vehicular speeds will lower from 17 km per hour to just 11 kmph. Not surprisingly, the study notes that the highest increases are from the road dust and construction dust which will increase by 80%. The transport sector will see vehicle exhaust emissions increasing by 50%.

“Even the master plan shows that trips by private vehicles will rise at the cost of public transport. Whatever is gained through newer vehicle models and fuels will be nullified by the increasing vehicular fleet in the city,” said Dr. Guttikunda. Policies for infrastructure development should be complemented by a policy that incentivises those travelling in motor vehicles towards public transport, he said.

“As we have seen in Delhi, it is a small fraction of motorists who shift towards metro, while the majority are those who used to travel by some form of public transport. There must be policies to change this behaviour (higher parking charges, for instance) which can dissuade the use of private transport,” he said.