Car ride on highways not good for  lungs, says study

HYDERABAD: Planning to travel by highway in your car anytime soon? Then may be you should reconsider your decision for the sake of safeguarding your health from air pollution. 
A study conducted by researchers from Indian Institute of Technology (IIT) - Kharagpur on exposure to air pollutants, particulate matter2.5  (PM2.5) and carbon monoxide (CO), on a 200 kilometer stretch of highway, has revealed that travelling by bus is the best option. 

For the study titled ‘A comparison of personal exposure to air pollutants in different travel modes on national highways in India’ that was published recently in Science of the Total Environment journal, the researchers travelled the stretch of Bhadrachalam to Vijayawada - 170km  between Bhadrachalam in Telangana to Ibrahimpatnam in Andhra Pradesh and further 30 km from Ibrahimpatnam to Vijayawada and measured the PM2.5 and CO concentrations. 

They found that the exposure to PM2.5 concentration was lowest in car if Air Conditioning is turned on, but at the same time CO exposure was highest in the same case. In contrast, it was observed that although PM2.5 exposure was found to be higher in bus than car with its AC turned on, it was lower than the exposure in car without AC. Importantly, it was also found that CO exposure was lowest in bus when compared to car, with and without AC turned on. PM2.5 exposure levels in the car (without AC) were found to be 1.7 times the exposures in the car (with AC) and 1.4 times in bus. 

Why are cars bad?
Researchers mentioned three possible reasons for higher PM2.5 concentrations inside car with windows rolled down than the bus - small size of car which results in higher concentration of the particulate matter inside the car, short distance between space inside car and the road as compared to bus which helps in decreasing the amount of exhaust from vehicles on road from getting into the bus and third reason being high speed at which a car travels, resulting in higher inflow of pollutant inside the car thus exposing the commuters to higher concentrations of PM2.5. One reason behind CO being recorded higher in car than bus, is the emissions leakage from car’s exhaust into the car-cabin.