Thorax 61:585-591 doi:10.1136/thx.2005.051730
  • Environmental exposure

Association between air pollution and general practitioner visits for respiratory diseases in Hong Kong

  1. T W Wong1,
  2. W Tam1,
  3. I Tak Sun Yu1,
  4. Y T Wun1,
  5. A H S Wong1,
  6. C M Wong2
  1. 1Department of Community and Family Medicine, The Chinese University of Hong Kong, Hong Kong, China
  2. 2Department of Community Medicine, The University of Hong Kong, Hong Kong, China
  1. Correspondence to:
    Professor T W Wong
    School of Public Health, Prince of Wales Hospital, Shatin, Hong Kong, China; twwong{at}
  • Received 15 August 2005
  • Accepted 26 February 2005
  • Published Online First 14 March 2006


Background: Few studies have explored the relation between air pollution and general practitioner (GP) consultations in Asia. Clinic attendance data from a network of GPs were studied, and the relationship between daily GP consultations for upper respiratory tract infections (URTI) and non-URTI respiratory diseases and daily air pollutant concentrations measured in their respective districts was examined.

Methods: A time series study was performed in 2000–2002 using data on daily patient consultations in 13 GP clinics distributed over eight districts. A Poisson regression model was constructed using the generalised additive model approach for each GP clinic, and associations with daily numbers of first visits for URTI were sought for daily concentrations of the following air pollutants: SO2, NO2, O3, PM10, and PM2.5. A summary relative risk of first visits to the GP for URTI per unit increase in concentration for each air pollutant was derived using a random effect model. First visits for non-URTI respiratory diseases were analysed in three GP clinics.

Results: Significant associations were observed between first visits for URTI and an increase in the concentrations of NO2, O3, PM10, and PM2.5. The excess risk was highest for NO2 (3.0%), followed by O3 (2.5%), PM2.5 (2.1%), and PM10 (2.0%). Similar associations with these air pollutants were found for non-URTI respiratory diseases.

Conclusions: These results provide further evidence that air pollution contributes to GP visits for URTI and non-URTI respiratory diseases in the community.


  • Published Online First 14 March 2006

  • This project was partly funded by the Environmental Protection Department of Hong Kong.

  • Competing interests: none declared.