Article Text

Download PDFPDF
Weather inference and daily demand for emergency ambulance services
  1. H T Wong,
  2. P C Lai
  1. Department of Geography, The University of Hong Kong, Hong Kong SAR, PR China
  1. Correspondence to H T Wong, Department of Geography, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, PR China; frankwong{at}


Aim To examine weather effects on the daily demand for ambulance services in Hong Kong.

Methods Over 6 million cases of emergency attendance from May 2006 through April 2009 (3 years) were obtained from the Hospital Authority in Hong Kong. These cases were further stratified by age, triage levels, hospital admission status, comprehensive social security assistance (CSSA) recipients and gender. The stratification was used to correlate against weather factors to assess the dependency of these variables and their effects on the daily number of ambulance calls. Adjusted-R2 values obtained from the regression analysis were used as a measure for evaluating predictability.

Results The adjusted-R2 of emergency cases by age groups showed proportional correlation with weather factors, which was more significant in older patients (0.76, p<0.01) than young patients (0.10, p<0.05). Furthermore, patients with more severe conditions were shown to have a higher adjusted-R2 (0.63, p<0.05 for critical as opposed to 0 for non-urgent patients). Weather effects were also found more significant in women (0.50, p<0.01) and CSSA recipients (0.54, p<0.01) when compared against their corresponding reference groups (respectively men at 0.46, p<0.01 and non-CSSA recipients at 0.45, p<0.01). Moreover, average temperature appeared to be a major weather effect.

Conclusions The presence of strong weather effects among different target groups indicates possibility for the development of a short-term forecast system of daily ambulance demand using weather variables. The availability of such a forecast system would render more effective deployment of the ambulance services to meet the unexpected increase in service demands.

  • Weather
  • ambulance
  • emergency medical services
  • multiple regression analysis
  • emergency ambulance systems
  • environmental medicine
  • wounds
  • research

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.


  • Funding We are grateful for funding support from the University of Hong Kong GRF Incentive Award 2008-09 for the acquisition of research data.

  • Competing interests None.

  • Provenance and peer review Not commissioned; externally peer reviewed.

Linked Articles

  • Primary survey
    Ian K Maconochie