atmosphere Article
Long-Term Atmospheric Visibility Trends and Characteristics of 31 Provincial Capital Cities in China during 1957–2016 Weicong Fu 1,2,3,4 , Ziru Chen 1 , Zhipeng Zhu 1 , Qunyue Liu 1,2 , Jinda Qi 5 , Emily Dang 4 , Minhua Wang 1 and Jianwen Dong 1, * 1
2 3 4 5
*
College of Landscape Architecture, Fujian Agriculture and Forestry University, Fuzhou 350002, China;
[email protected] (W.F.);
[email protected] (Z.C.);
[email protected] (Z.Z.);
[email protected] (Q.L.);
[email protected] (M.W.) Urban Forestry Research in Action, Department of Forest Resources Management, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada Collaborative for Advanced Landscape Planning, Faculty of Forestry, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada Faculty of Forestry, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada;
[email protected] Faculty of Built Environment, University of New South Wales, Sydney 2052, Australia;
[email protected] Correspondence:
[email protected]; Tel.: +86-0591-8378-9179
Received: 11 June 2018; Accepted: 15 August 2018; Published: 17 August 2018
Abstract: Millions of pulmonary diseases, respiratory diseases, and premature deaths are caused by poor ambient air quality in developing countries, especially in China. A proven indicator of ambient air quality, atmospheric visibility (AV), has displayed continuous decline in China’s urban areas. A better understanding of the characteristics and the factors affecting AV can help the public and policy makers manage their life and work. In this study, long-term AV trends (from 1957–2016, excluding 1965–1972) and spatial characteristics of 31 provincial capital cities (PCCs) of China (excluding Taipei, Hong Kong, and Macau) were investigated. Seasonal and annual mean values of AV, percentage of ‘good’ (≥20 km) and ‘bad’ AV (20 Km and 20 km and
