By Dr Joy Shumake-Guillemot (WHO/WMO Joint Climate and Health Office), Liisa Jalkanen (WMO Secretariat) and Heather Adhair-Rohani (WHO)
Air quality, weather and climate, and human health are closely linked. These interdependencies are becoming ever more evident and health professionals ever more reliant on meteorological and climate services to help anticipate and manage the health risks of poor air quality. Over the last century, poor air quality has become a critical environmental, economic, and health problem around the world as industrial growth and economic development have caused massive increases in air pollutants.
Nitrogen oxides, ozone, volatile organic compounds (VOCs), sulphur dioxide and particulate matter (PM) are accruing in our atmosphere, especially due to inefficiencies in transportation, energy production, energy use and industry. Chemical components and pollutants emitted into the atmosphere undergo chemical transformations and get transported far and wide, depending on the climate and weather. Air quality is also compromised by natural contaminants such as aeroallergens – pollen, moulds – smoke from wild fires, airborne sand and dust as well as by personal behaviour such as tobacco smoke exposure or indoor burning of solid fuels. When inhaled, these contaminants penetrate deeply into the respiratory system and cause a myriad of damaging biological reactions in the human body. As a result, air pollution is now the world’s largest single environmental health risk.
Air quality and health
In recent months, the World Health Organization (WHO) has released alarming figures on the impact of ambient (surrounding outdoor) air quality on human health. The Global Burden of Disease assessment indicated that 3.7 million premature deaths per year, representing 6.7% of the global disease burden, could be attributed to ambient particulate matter pollution, placing it among the top health risk factors globally. A further 152 000 remature deaths were attributable to ozone exposure. These premature deaths resulted from ischemic heart disease (IHD), 40%; stroke, 40%; chronic obstructive pulmonary disease (COPD), 11%; lung cancer, 6%; and acute lower respiratory infections (ALRI) in children, 3%. Additionally, the figure below shows that ambient air related diseases disproportionately affect people in low- and middle-income countries, where 88% of the 3.7 million premature deaths occur, mostly in the WHO Western Pacific and South-East Asia regions.1
Deaths attributable to ambient air pollutuion in 2012 (000s)
Short-term exposure to air pollutants can have many serious health effects that result in emergency medical care, especially following severe pollution episodes such as wild fires, dust and sand storms and urban smog during heat waves. However, long-term exposure to elevated levels of air pollution over time may have greater health effects than acute exposures. Fine particulate pollution, ozone, carbon monoxide, nitrogen and sulpher dioxides, and aeroallergens are the principle air contaminants of concern for human health.
Colourized electron microscope image of pollen from the sunflower family - Depending on weather and climate pollens can remain suspended in air for hours, causing allergy outbreaks far from their source at any time of the day.
The interdependent relationships between air pollution, weather and climate, and health are also tightly coupled with climate change: almost all non-CO2 climate-altering pollutants are hazardous to human health; weather and climate determine the location, timing and quantity of atmospheric pollutants that people may be exposed to, including aeroallergens; and air pollutants are altering the climate system itself. In particular, ozone and several components of fine particulate matter (PM2.5), such as black carbon, are Short-Lived Climate Pollutants that play an important role in climate change and both ecosystem and human health. Combined with accelerating urbanization, the inevitable range of effects that climate variability and climate change will have on air quality are expected to magnify human exposure to:
Particulate matter – wild fire smoke, smog, and dust; Ground-level ozone; Aeroallergens (pollens, moulds, harmful algal blooms); and Long range transport of pollutants and aeroallergens.
Air pollution can be especially detrimental in urban areas, where large numbers of people and emissions are concentrated, and urban heat island effects can amplify pollution levels. In fact, today, in most cities that monitor ambient air pollution, air quality fails to meet WHO guidelines for safe levels. The location of a city has a major effect on the air pollution experienced.
For example, in areas with high temperatures the use of air conditioning increases air pollution in the summer. In areas with cold winters, heating will have the same effect. Frequently, atmospheric inversion occurs causing pollutants to be trapped close to the ground, and making the exposure concentrations higher and long lasting. If surrounded by mountains, pollutants can be trapped within the basin causing a similar effect.
Role of meteorological community
Climate and weather – wind, temperature, precipitation and other meteorological factors – play a key role in the poor air quality that populations face. The meteorological community can assist global and local health partners to understand and reduce health risks of poor air quality, especially through:
- Monitoring – which needs to be done effectively in relevance to population exposures, measuring key contaminants to standards that can be compared across locations. Monitoring of PM2.5 should have the highest priority, followed by ozone, black carbon, and NO2.
- Modelling – to understand risk dynamics and make case studies to assist in, for example, urban planning. Inverse modelling may be used for emission estimations.
- Forecasting – to anticipate specific hazardous conditions in order to take action to improve air quality, to advise the public by, for example, providing Air Quality Indexes.
- Long-term projections – to forecast future trends and problem areas in order to inform policy and multi-sectoral nterventions to protect health.
At the global level, WMO coordinates the Global Atmosphere Watch (GAW) network, responsible for systematic, long-term global monitoring, analysis and assessment of atmospheric chemical and physical parameters. The system serves both developed and developing countries, and includes training of field personnel. GAW is concentrating its efforts on addressing global and regional questions such as greenhouse gases, stratospheric ozone depletion, biomass burning, sand and dust storms and the formation of photochemical smog.
WMO is increasing its focus on megacities and large urban complexes, due to their concentration of pollution sources and large populations at risk. Its aim is to develop strategies to help megacities deal with weather, climate and environmental problems, improve related services; enhance environmental monitoring and modelling capabilities; and generate useful case studies to help understand air pollution, health and climate connections in different types of megacities.
GAW Urban Research Meteorology and Environment (GURME) is building capacity to provide air quality modelling and forecasting, including improvement of related pollutant and meteorological observations. This is currently being done mostly through pilot projects, for instance, in Beijing, Moscow, Shanghai, several Indian cities including New Delhi and Pune, and in Latin America. The projects consider the full chain of action from research to operations to provision of products and services. In 2012, GURME, together with the International Global Atmospheric Chemistry (IGAC), published a report on the Impacts of Megacities on Air Pollution and Climate, summarizing the current situations of megacities on different continents.
At the national level, meteorological and hydrological services, together with partners such as environmental services, play a fundamental role in air quality monitoring. Some produce air quality indexes and air quality forecasts that help raise awareness and inform decisions about air pollution. Where available, these services have shown to be useful instruments for decision-makers to improve the predicted air quality, for instance, by limiting emissions from traffic, power plants and industrial activity. Air quality forecasts and indexes are also important public communication tools. They can help people plan activities to avoid exercise and strenuous work outside when the pollution is high, and help hospitals prepare accordingly for a potential increase of patients with cardiovascular and respiratory complications. National meteorological and hydrological services are working together with the health community to provide a better nderstanding of how local meteorological conditions trigger hazardous air pollution episodes, and to provide elevant, easily understandable, and reliable information to inform actions that can keep populations healthy.
The Shanghai Meteorological Service (SMS) of the China Meteorological Administration (CMA), for example, provides a range of climate services specifically tailored for the needs of local health authorities, especially for the preparation for large events such as the 2010 World Expo. The forecasts of specific environmental health exposures are produced for pollen, ultraviolet (UV) radiation, haze and ozone, influenza transmission, and extreme temperatures as well as foodborne outbreaks related to temperature. With forecasts of these local hazards hospitals can plan staffing, notify respiratory and cardiac specialists of likely increased cases during specific periods, prepare pharmacies to have adequate supplies of essential medicines on hand, and alert high risk patients and the public to modify their behaviour to avoid exposure to poor air quality.
Cyclists shield their faces in Hanoi, Vietnam. / © Simone D. McCourtie, World Bank
Role of health community
The health community is also taking preventive action to address the health risks of air pollution. In addition to providing guideline levels of pollutants for clean air, the WHO is collaborating with other international organizations to establish a Global Platform on Air Quality and Health. The Global Platform will provide Internet-based open-access to data and information, facilitating search for a wide range of users on human exposures to ambient air pollution; on health impacts; and on effective interventions for air pollution reduction. A combination of data from atmospheric transport models and satellite remote sensing, calibrated with ground-level air quality monitoring, will be used as inputs to derive integrated estimates of population exposure to air pollution. Once established, the Global Platform will be a unique clearinghouse, providing relevant air quality and health information to stimulate policy development, acilitating monitoring and evaluation, and assisting in building capacity to prevent diseases associated with air pollution in all countries of the world.
A patient receives treatment in Tajikistan / © Matt Wreford
Both WMO and WHO are also collaborating with the Climate and Clean Air Coalition (CCAC) to reduce shortlived climate pollutants. CCAC is a voluntary partnership of governments, intergovernmental organizations, representatives of the private sector, the environmental community and other members of civil society that addresses the challenge of short-lived climate pollutants. The Coalition builds on the joint UNEP/WMO Integrated Assessment of Black Carbon and Tropospheric Ozone. The CCAC will provide benefits for both immediate health protection and address climate change.
Developing climate services for health
Air quality and human health is a priority for joint actions. The meteorological community generates a wide range of data, products and services that are essential instruments for the health community to effectively advocate for policies that protect individuals, and put in place actions that can avoid illness and death due to poor air quality. Awareness of the potential health applications of weather and climate monitoring, modelling, and forecasting is rising steadily. The publication in 2012 of the WMO/WHO Atlas of Health and Climate stimulated public and scientific interest. The new WHO/ WMO joint office for climate and health will further help raise awareness, build capacity, and strengthen relevant partnerships to address this issue. Potential exists worldwide to improve the transfer and use of available weather and climate products. However, further steps are needed to improve dialog and catalyze partnerships between health and meteorological professionals at global, regional, national and city levels.
Smokestacks in an industrial town in Estonia / © Curt Carnemark
The Global Framework for Climate Services (GFCS) is bringing together the WMO network of national meteorological and hydrological services with, amongst others, the WHO health policy and science professionals to define the operational management needs of the health community for weather and climate products. Countries and partners implementing the GFCS should consider how national meteorological and hydrological services, and other meteorological actors, could contribute to improving community health through joint efforts to monitor, alert and manage the impacts of hazardous air quality. The interdependencies of air pollution, climate and weather, and human health call for actionable knowledge that is only possible through joint actions.
WHO. 2006. Air Quality Guidelines Global Update 2005: Particulate Matter, Ozone, Nitrogen Dioxide, and Sulfur Dioxide. Copenhagen, Denmark: World Health Organization.
- 2013. Review of Evidence on Health Aspects of Air Pollution – REVIHAAP Project: Final Technical Report.
- 2014a. “7 Million Premature Deaths Annually Linked to Air Pollution.” WHO. (September 20, 2014).
- 2014b. “Air Quality Deteriorating in Many of the World’s Cities.” WHO. (September 19, 2014).
- 2014c. “Burden of Disease from Ambient Air Pollution for 2012: Summary of Results.”
- 2014d. “Mortality from Ambient Air Pollution.” WHO. (September 20, 2014).
WMO/IGAC (2012) Tong Zhu, Megan Melamed, David Parrish, Michael Gauss, Laura Gallardo Klenner, Mark Lawrence, Abdourahamane Konare and Cathy Liousse. Impacts of Megacities on Air Pollution and Climate
1 The WHO South East Asia Region has 11 Member States: Bangladesh, Bhutan, Democratic People’s Republic of Korea, India, Indonesia, Maldives, Myanmar, Nepal, Sri Lanka, Thailand, Timor-Leste. The Western Pacific Region has 37 Member States: including China, Japan, the Republic of Korea, Philippines, Mongolia, Singapore, Australia, New Zealand, Viet Nam, Malaysia, Cambodia, and the Pacific Islands.