Why does the sky show blue sky and white clouds after a typhoon or between storms?

As soon as the typhoon left, it immediately returned to sunny, and the clear sky was particularly blue against the background of large white clouds. According to the monitoring of the Meteorological Observatory, yesterday's visibility was 15-20km and the air humidity was 5 1%. Meteorologists said that the sky was so transparent that Typhoon Senlake (13) contributed a lot. At present, although it has left, the high-pressure weather system left behind and the low pressure over Nanjing have formed a strong longitudinal pressure difference, which "sucks" the suspended pollution particles away, so that the upper and lower air exchanges, the visibility is improved, and the sky naturally becomes blue and clear.