A new study shows that fine dust density in the air is the highest in the capital Seoul just after the morning rush hour. 

Seoul National University Professor Ho Chang-hoi published a report in a journal issued by the National Institute of Meteorological Sciences, analyzing that fine dust levels peak between 10 and 11 a.m. in Seoul.

The report measured the amount of air pollutants in 25 Seoul districts and on six main roads from October to February each year from 2001 to 2018.

The professor said the results imply the key factor contributing to a fluctuation in daily fine dust levels is the gas emissions from vehicles. He also argued that a decrease in fine dust did not lead to lower levels of carbon dioxide or the ozone.

He called for more related research and effective policy measures.