https://search.naver.com/search.naver?where=nexearch&sm=tab_etc&mra=blQ3&qvt=0&query=서울 미세먼지

Or https://www.airkorea.or.kr/eng/

☝️use above links for checking air quality each day. For Naver 예보(prediction) page, 오전 is Before noon and 오후 is afternoon. If it’s green, I’d say go for it.