ABSTRACT
<p><b>OBJECTIVE</b>The study is to investigate the associations between visibility, major air pollutants and daily counts of hospital admission in Shanghai, China.</p><p><b>METHODS</b>Daily data on hospital admission, visibility, and air pollution during 2005-2008 were obtained from the Shanghai Insurance Bureau (SHIB), Shanghai Meteorological Bureau, and Shanghai Environmental Monitoring Center, respectively. The generalized additive model (GAM) with penalized splines was used to examine the associations between daily visibility and hospital admission.</p><p><b>RESULTS</b>Among various pollutants, PM(2.5) showed strongest correlation with visibility. Decreased visibility was significantly associated with increased risk of hospital admission in Shanghai. An inter-quartile range decrease in the 2-day (L01) moving average of visibility corresponded to 3.66% (95%CI: 1.02%, 6.31%), 4.06% (95%CI: 0.84%, 7.27%), and 4.32% (95%CI: 1.67%, 6.97%) increase of total, cardiovascular, and respiratory hospitalizations, respectively.</p><p><b>CONCLUSION</b>Our analyses provide the first piece of evidence in China, demonstrating that decreased visibility has an effect on hospital admission, and this finding strengthens the rationale for further limiting air pollution levels in Shanghai.</p>