Public health responses to heat waves

Introduction

EuroHEAT is a project coordinated by the Global Change and Health programme of the WHO Regional Office for Europe and co-funded by DG SANCO in the framework of the EU Public Health Programme. The project quantified the health effects of heat in European cities and identified options for improving the preparedness and response of health systems to protect health from heat waves. Its activities contributed to the implementation of the Declaration of the Fourth WHO Ministerial Conference on Environment and Health and of the EC Environment and Health Action Plan. The core EuroHEAT team was composed of representatives from 7 European scientific institutions and supported by an advisory committee of 19 experts from 14 countries and the EC.

The adverse health effects of heat waves are largely preventable. EuroHEAT recommends developing and implementing heat-health action plans at national and regional level in Europe, to prevent, react upon, and contain heat-related risks to health.

What is a heat wave and how does it affect health?

There is no standard definition for a heat wave. EuroHEAT defined a heat wave as a period where the maximum apparent and the minimum temperature are over the 90th percentile of the monthly distribution for at least two days. Heat waves characterized by long duration and high intensity have the highest impact on mortality. In the nine European cities analyzed by EuroHEAT (Athens, Barcelona, Budapest, London, Milan, Munich, Paris, Rome and Valencia), the estimated increase in mortality during heat waves ranged from 7.6% to 33.6%. The impact of long heat waves (i.e., more than four days) was 1.5 to 5 times higher than that of short heat waves.

There is growing evidence from EuroHEAT that the effects of heat wave days on mortality are larger when ozone or PM10 (particulate matter ≤ 10µm diameter) levels are high, particularly among the elderly (75-84 years). Future heat wave studies thus need to adjust their estimated effects for air pollution levels. The mortality increase due to the combined effect of heat and air pollution can be reduced by decreasing exposure to PM10 and ozone on hot days.

Heat-related deaths are expected to grow as a consequence of projected further increase in heat wave frequency, intensity and duration, due to climate change. For example in 2030, under a high CO2 emission scenario, more than 400 attributable deaths per year are expected in Athens, Budapest, Paris, and Rome.

The Web-based climate information decision support

As part of the EU Project EuroHEAT, the German Weather Service has developed an online tool providing medium-term forecasting of heat. This tool, which maps the probability of a forthcoming heat wave, can support health services in planning.

The online Climate Information Decision Support Tool is a tool to provide decision makers with early information about potential dangers to human health from heat waves. This timely information gives health systems time to prepare in case a heat wave is forecast. This medium range heat information is no substitute for the operational national Heat Health Warning Systems (HHWSs). In contrast to a traditional HHWS that has, in general, lead times of between 0 and 3 days and provides deterministic heat warnings, the climate information decision support tool provides probabilistic medium-range heat information. Medium range in meteorology means lead times of between 3 and 10 (15) days. The uncertainty of the weather forecast for the medium-range is naturally much higher than for short-range forecasts. Each day a forecast of the probabilities for heat events for the following 9 days is issued. The user has the possibility of displaying either the forecast issued on the current day or the forecasts that have been issued for the past 9 days. They can thus track the development of the heat wave and compare the forecasts with the warnings issued by the national HHWS. The Climate Information Decision Support Tool provides in addition information about national HHWSs. The map is based mainly on a questionnaire that was sent to the National Meteorological Services in spring 2006.

See online tool providing medium-term forecasting of heat
See How to use the medium range heat information tool?pdf
See Climate Information Decision Support Tool for Heat in Europe – Scientific backgroundpdf
See national Heat Health Warning Systems (HHWSs)


Key features of heat-health action plans

The EuroHEAT final meeting took place in Bonn (22-23 March, 2007) supported by WHO, DG SANCO and the project CANICULE - Etude de l’impact de la canicule d’août 2003 sur la population européenne.

The final reportpdf of the conference summarizes the discussion of the results of the EuroHEAT project and proposes key recommendations for heat-health action plans:

  1. Establishment of multi-purpose collaborative mechanisms, between bodies and institutions, and a lead body to coordinate responses. This includes definition of roles and responsibilities for actors at the national/regional level. Exploring financial incentives, legislation, and synergies with the International Health Regulations (2005) and existing national disaster plans is advised.
  2. Availability of accurate and timely alert systems. Heat-health warning systems (HHWS) should be developed in collaboration with meteorological services to trigger a warning, determine the threshold for action, and communicate the risks. There is no best HHWS: an effective HHWS is targeted to the local needs, is accurate and timely. Experiences of various countries should be shared.
  3. Avoidance or reduction of heat exposure. As part of the plan, measures to reduce exposure should be taken, such as: individual behavioural measures, short-, medium- and long-term housing measures and long-term improved urban planning, building design, transport and energy policies. Medium- and short-term options are available for passive cooling such as cool paints, external shading, radiant barriers and insulation of buildings. Advice should be given to the public on how to best reduce indoor temperatures, with particular attention to avoiding pollutants, measures to avoid electricity shut-offs and reduced water availability. Early development and implementation of urban planning, building design, energy and transport policies will ultimately reduce exposure to heat.
  4. Particular care for vulnerable populations. It is helpful to identify groups at high risk before summer and plan and target interventions accordingly. Community organizations, medical practitioners and care providers play an important role in identifying persons at risk, in advising individuals at high risk from heat-related illness and following up persons at particular risk.
  5. Provision of health care, social services and infrastructure. This includes summer health workforce planning, health service provision, and training of health personnel and other interest groups. It is advisable that care homes and hospitals meet the EU criteria for the thermal indoor environment to prevent heat-related illness in patients and staff. Emergency departments of hospitals could be alerted to heat waves to better manage an increase in patient admissions.
  6. Heat-related health information developed in advance. As heat waves are likely to occur every summer although in different locations in Europe, it is advisable to establish a communication plan before the summer. This plan should include advice to the population on how to protect oneself and others, how to reduce heat exposure indoors, how to recognize heat-related symptoms, as well as targeted information to particular groups such as health care institutions and care givers.
  7. Real-time health surveillance incorporated into the planning process. Real-time surveillance is important to detect early impacts of hot weather, to potentially modify interventions and to inform about abnormal outbreaks or clusters of health impacts. The most useful real-time data are all cause mortality, emergency calls, emergency department visits, hotlines and GP records. They should be available no later than within one to two days.
  8. Monitoring and evaluation components and criteria. It is crucial at the end of the summer to evaluate whether the heat-health action plan has worked. This includes an a priori definition of process and outcome criteria. Monitoring health outcomes over time in relation to heat waves is another important component of the plan.

See Euro Heat meetings
See Heat-health action plans - Guidance (2008)
See Ten information sheets on public health responses to heat wavespdf
See Improving public health responses to extreme weather/heat-waves - Technical summary - 2009pdf


What is a heat wave and how does it affect health?

There is no standard definition for a heat wave. EuroHEAT defined a heat wave as a period where the maximum apparent and the minimum temperature are over the 90th percentile of the monthly distribution for at least two days. Heat waves characterized by long duration and high intensity have the highest impact on mortality. In the nine European cities analyzed by EuroHEAT (Athens, Barcelona, Budapest, London, Milan, Munich, Paris, Rome and Valencia), the estimated increase in mortality during heat waves ranged from 7.6% to 33.6%. The impact of long heat waves (i.e., more than four days) was 1.5 to 5 times higher than that of short heat waves.

There is growing evidence from EuroHEAT that the effects of heat wave days on mortality are larger when ozone or PM10 (particulate matter ≤ 10µm diameter) levels are high, particularly among the elderly (75-84 years). Future heat wave studies thus need to adjust their estimated effects for air pollution levels. The mortality increase due to the combined effect of heat and air pollution can be reduced by decreasing exposure to PM10 and ozone on hot days.

Heat-related deaths are expected to grow as a consequence of projected further increase in heat wave frequency, intensity and duration, due to climate change. For example in 2030, under a high CO2 emission scenario, more than 400 attributable deaths per year are expected in Athens, Budapest, Paris, and Rome.

The Web-based climate information decision support

As part of the EU Project EuroHEAT, the German Weather Service has developed an online tool providing medium-term forecasting of heat. This tool, which maps the probability of a forthcoming heat wave, can support health services in planning.

The online Climate Information Decision Support Tool is a tool to provide decision makers with early information about potential dangers to human health from heat waves. This timely information gives health systems time to prepare in case a heat wave is forecast. This medium range heat information is no substitute for the operational national Heat Health Warning Systems (HHWSs). In contrast to a traditional HHWS that has, in general, lead times of between 0 and 3 days and provides deterministic heat warnings, the climate information decision support tool provides probabilistic medium-range heat information. Medium range in meteorology means lead times of between 3 and 10 (15) days. The uncertainty of the weather forecast for the medium-range is naturally much higher than for short-range forecasts. Each day a forecast of the probabilities for heat events for the following 9 days is issued. The user has the possibility of displaying either the forecast issued on the current day or the forecasts that have been issued for the past 9 days. They can thus track the development of the heat wave and compare the forecasts with the warnings issued by the national HHWS. The Climate Information Decision Support Tool provides in addition information about national HHWSs. The map is based mainly on a questionnaire that was sent to the National Meteorological Services in spring 2006.

See online tool providing medium-term forecasting of heat
See How to use the medium range heat information tool?pdf
See Climate Information Decision Support Tool for Heat in Europe – Scientific backgroundpdf
See national Heat Health Warning Systems (HHWSs)

Key features of heat-health action plans

The EuroHEAT final meeting took place in Bonn (22-23 March, 2007) supported by WHO, DG SANCO and the project CANICULE - Etude de l’impact de la canicule d’août 2003 sur la population européenne.

The final reportpdf of the conference summarizes the discussion of the results of the EuroHEAT project and proposes key recommendations for heat-health action plans:

  1. Establishment of multi-purpose collaborative mechanisms, between bodies and institutions, and a lead body to coordinate responses. This includes definition of roles and responsibilities for actors at the national/regional level. Exploring financial incentives, legislation, and synergies with the International Health Regulations (2005) and existing national disaster plans is advised.
  2. Availability of accurate and timely alert systems. Heat-health warning systems (HHWS) should be developed in collaboration with meteorological services to trigger a warning, determine the threshold for action, and communicate the risks. There is no best HHWS: an effective HHWS is targeted to the local needs, is accurate and timely. Experiences of various countries should be shared.
  3. Avoidance or reduction of heat exposure. As part of the plan, measures to reduce exposure should be taken, such as: individual behavioural measures, short-, medium- and long-term housing measures and long-term improved urban planning, building design, transport and energy policies. Medium- and short-term options are available for passive cooling such as cool paints, external shading, radiant barriers and insulation of buildings. Advice should be given to the public on how to best reduce indoor temperatures, with particular attention to avoiding pollutants, measures to avoid electricity shut-offs and reduced water availability. Early development and implementation of urban planning, building design, energy and transport policies will ultimately reduce exposure to heat.
  4. Particular care for vulnerable populations. It is helpful to identify groups at high risk before summer and plan and target interventions accordingly. Community organizations, medical practitioners and care providers play an important role in identifying persons at risk, in advising individuals at high risk from heat-related illness and following up persons at particular risk.
  5. Provision of health care, social services and infrastructure. This includes summer health workforce planning, health service provision, and training of health personnel and other interest groups. It is advisable that care homes and hospitals meet the EU criteria for the thermal indoor environment to prevent heat-related illness in patients and staff. Emergency departments of hospitals could be alerted to heat waves to better manage an increase in patient admissions.
  6. Heat-related health information developed in advance. As heat waves are likely to occur every summer although in different locations in Europe, it is advisable to establish a communication plan before the summer. This plan should include advice to the population on how to protect oneself and others, how to reduce heat exposure indoors, how to recognize heat-related symptoms, as well as targeted information to particular groups such as health care institutions and care givers.
  7. Real-time health surveillance incorporated into the planning process. Real-time surveillance is important to detect early impacts of hot weather, to potentially modify interventions and to inform about abnormal outbreaks or clusters of health impacts. The most useful real-time data are all cause mortality, emergency calls, emergency department visits, hotlines and GP records. They should be available no later than within one to two days.
  8. Monitoring and evaluation components and criteria. It is crucial at the end of the summer to evaluate whether the heat-health action plan has worked. This includes an a priori definition of process and outcome criteria. Monitoring health outcomes over time in relation to heat waves is another important component of the plan.

See Euro Heat meetings
See Heat-health action plans - Guidance (2008)
See Ten information sheets on public health responses to heat wavespdf
See Improving public health responses to extreme weather/heat-waves - Technical summary - 2009pdf