1g 그램 먼지 1nano 환산했을 때 먼지數
<iframe width="1840" height="1035" src="https://www.youtube.com/embed/TQ9RV6yD0dg" title="Local researchers create new nano-fiber filter to counter growing ultra fine dust issues" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen></iframe>