Air pollution is getting much more serious these years, and it corrodes our health little by little without notice. I’m not being alarmist, but air pollution contains not only particulate matters(PM) but also SO2, NO2, PAHs…etc., which will lead to sickness or even cancer. There are some commercial activated carbons that has been published available to filter these suspended material, and active carbon is the most commercial and widely uses one, we apply it on the inner surface of our channel so it won’t interfere air movement.