Diesel trucks to blame for smog on Manali-Leh highway
There’s no getting away from air pollution, with new research finding high levels of smog from vehicular emissions along India’s high mountain highways.
Researchers from the University of Cincinnati (UC) in the US found sulphur pollution along the Manali-Leh highway, which winds 490km through Tanglang La , one of the highest motorable mountain passes in the world at 17,480 feet. “We measured incredibly high amounts of sulphur close to the highway. Some of those values are the highest ever reported in the literature and were likely connected to truck traffic,” said Brooke Crowley, assistant professor of geology and anthropology, who did the study with UC graduate Rajarshi Dasgupta.
For the study, soil samples collected along the highway from a depth of 3, 9 and 15cm were tested for hydrocarbons from wood and cow-dung emissions from cooking and heating, along with sulphur, total organic compound and 10 types of heavy metal. It found low levels of heavy metals but high concentrations of sulphur, a major pollutant in the exhaust of dieselpowered engines. More than 50,000 vehicles use the highway each year, mostly during summer when passes are free of snow. The highest sulphur content was found at the base of narrow ridges that are most prone to rockslides, where trucks wait as the road is cleared of rubble.
Sulphur dioxide (SO2) is a major constituent of smog. Short-term exposure inflames the respiratory system to make breathing difficult and trigger asthma attacks. So2, along with other sulphur oxides (SOx), react with other pollutants to form suspended particles that penetrate deep into the airways and lungs to cause asthma, chronic obstructive lung disease, heart attacks and strokes.
“At first glance, it’s easy to consider the region to be a pretty pristine place. But there are environmental impacts from humans,” said Crowley, who published the findings in
“There is no pristine environment left. You see black snow deposited on glaciers and snowfields in Tibet,” said professor Lewis Owen, head of geology department, UC.