A total of 30 million trees will be planted in Seoul by 2022 and two large forests will be formed as part of efforts to mitigate worsening air pollution and urban heat, the Seoul Metropolitan Government announced Tuesday. 

The city government plans to plant an additional 15 million trees, having already planted 15 million trees between 2014 and last year.

Thirty million trees would have the effect of reducing particulate pollution generated by 64,000 aged diesel cars per year, and producing oxygen equivalent to the amount that 21 million adults inhale per year, the city said.

Two forests will be created by 2021 in partnership with the Korea Forest Service near Gwanaksan in southern Seoul and Bukhansan in northern Seoul.

Starting with 10 school zones this year, forests will be created in 30 school zones by 2021.

Car-only highways such as the Olympic Expressway and the Gangbyeon Expressway will be lined with 2.1 million more trees by 2022, the city said.

A total of 480 billion won will be spent on the project over the next four years.

By Ock Hyun-ju (laeticia.ock@heraldcorp.com)