A new study finds that the concentration level of phytoncide is the highest during summer and between 10 a.m. and noon.
 
North Chungcheong Province’s health and environment research institute found that the level of phytoncide stood at 796 parts per trillion by volume (pptv) at 10 a.m. and 700 pptv at noon.

The institute released the study after estimating the level of phytoncide in four spots in North Chungcheong province last year. Phytoncide refers to organic compounds that plants produce to protect against diseases and harmful insects or germs. It’s considered to be a healing substance provided by forests as it is effective in boosting immunity and calming senses.
 
In particular, the institute said in city parks that have forests were found to produce significant amounts of phytoncide and stressed the need to enhance city parks.