Podatke o kvaliteti zraka obezbjeđuje: the Weather Underground (wunderground.com) and the Hunan Environmental Protection Agency (湖南省环境保护厅) (sthjt.hunan.gov.cn) and the China National Urban air quality real-time publishing platform (全国城市空气质量实时发布平台) (113.108.142.147:20035)