The reason is that ventilation should be done for 10 to 15 minutes

(1)according to the concentration of carbon dioxide
(2)a change in oxygen concentration
(3)carbon dioxide
(4)6:00 a.m
(5)Close the window and after a while, the oxygen inside the room
(6)The concentration is decreasing
(7)The concentration of carbon dioxide goes up
(8)That is why regular ventilation is essential for your health
(9)However, if ventilation is prolonged, fine dust will flow into the room
(10)I wonder how much fine dust would come in to ventilate
(11)It’s a picture I took myself It’s a filter you put on the window frame. 2
(12)We’re replacing the lunar cycle