title: The association of air pollution with the patients' visits to the department of respiratory diseases.
abstract: BACKGROUND
  The objective of this study was to evaluate the impact of air particulate matter 2.5 (PM2.5) on the daily number of patients' visits to the Department of Respiratory Diseases in a local general hospital.
  
  
  METHODS
  The number of patients in outpatient department of respiratory diseases (ODRD) in a general hospital of Jinan, China, the air quality and meteorological data were collected for 1 year. By controlling the confounding factors such as "day of the week" effects and the meteorological factors, the generalized additive Poisson regression analysis was conducted to evaluate the impact of PM2.5 on the number of patients' visits to the ODRD.
  
  
  RESULTS
  Within two consecutive days, if the cumulative PM2.5 was less than 200 µg/m(3), the daily number of patients in the ODRD did not increase significantly; however, it increased dramatically when the concentration of PM2.5 particles reached the range between 200 and 400 µg/m(3).
  
  
  CONCLUSIONS
  There is a non-linear relationship between the concentration of atmospheric PM2.5 particles and the daily number of patients in the ODRD.
authors.affiliation: Basic Medical College of Shandong University of Traditional Chinese Medicine, Jinan, Shandong, China.
authors.forename: Yanran
authors.initials: Y
authors.lastname: Cai
authors.affiliation: Basic Medical College of Shandong University of Traditional Chinese Medicine, Jinan, Shandong, China.
authors.forename: Yumeng
authors.initials: Y
authors.lastname: Shao
authors.affiliation: Basic Medical College of Shandong University of Traditional Chinese Medicine, Jinan, Shandong, China.
authors.forename: Chenggang
authors.initials: C
authors.lastname: Wang
keywords: Daily number of patients; Generalized additive model; Outpatient department of respiratory diseases; Particulate matter 2.5