Unfavorable Weather Conditions Main Cause Fog-Haze Over Beijing-Tianjin-Hebei Region During COVID-19 Lockdown

At the end of December 2019, Coronavirus Disease 2019 (COVID-19) quickly spread throughout Hubei Province and other parts of China. During the 2020 Spring Festival, public activities were cancelled, people tried their best to stay at home, and human and industrial activities were reduced to a basic or minimum level. However,...