environmental risk to health
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In this in-depth question and answer interview with Charles Ndika Akong, Technical Officer and Dr Magaran Bagayoko, Senior Scientist at the World Health Organization (WHO) Regional Office for Africa (AFRO), we find out why air pollution is a major environmental risk to health

According to The World Health Organization (WHO) Regional Office for Africa, air pollution is contamination of the indoor or outdoor environment by any chemical, physical or biological agent that modifies the natural characteristics of the atmosphere. Household combustion devices, motor vehicles, industrial facilities and forest fires are common sources of air pollution.

Pollutants of major public health concern include particulate matter (PM), carbon monoxide, ozone, nitrogen dioxide and sulphur dioxide. Outdoor and indoor air pollution cause respiratory and other diseases, which can be fatal. We find out more about air pollution in this interview with Charles Ndika Akong and Magaran Monzon Bagayoko from the World Health Organization (WHO) Regional Office for Africa (AFRO).

Tell us about air pollution and how would you define it? What are the pollutants of major public health concern?

Air pollution is a major environmental risk to health. By reducing air pollution levels, countries can reduce the burden of disease from stroke, heart disease, lung cancer, and both chronic and acute respiratory diseases, including asthma.

In 2016, nine out of 10 people breathed air in which the concentration of air pollutants is above the limit set up by the WHO guidelines, and about 7 million people died of diseases attributable to air pollution. (1) Ambient (outdoor air pollution) in both cities and rural areas was estimated to cause 4.2 million premature deaths worldwide in 2016.

About 3.8 million deaths globally were attributed to household air pollution, with 734,000 of those deaths occurring in Africa because of the domestic use of solid fuels and kerosene for cooking, lighting and heating. Ambient air pollution caused approximately 439,000 deaths in the region.

The main air pollutants of public health concerns are:

  • Particulate matter (PM);
  • Ozone (O3 );
  • Nitrogen dioxide (NO2 ) and;
  • Sulphur dioxide (SO2).

By reducing air pollution levels, how can countries reduce the burden of disease from stroke, heart disease, lung cancer, and both chronic and acute respiratory diseases, including asthma?

The 2005 WHO Air quality guidelines offer global guidance on thresholds and limits for key air pollutants that pose health risks. The guidelines indicate that by reducing particulate matter (PM10) pollution from 70 to 20 micrograms per cubic metre (μg/m), we can cut air pollution-related deaths by around 15%.

In low- and middle- income countries including Africa, exposure to pollutants in and around homes from the household combustion of polluting fuels on open fires or traditional stoves for cooking, heating and lighting further increases the risk for air pollution-related diseases, including acute lower respiratory infections, cardiovascular disease, chronic obstructive pulmonary disease and lung cancer.

There are serious risks to health not only from exposure to PM, but also from exposure to ozone (O3), nitrogen dioxide (NO2) and sulphur dioxide (SO2). As with PM, concentrations are often highest largely in the urban areas of low- and middle-income countries. Ozone is a major factor in asthma morbidity and mortality, while nitrogen dioxide and sulphur dioxide also can play a role in asthma, bronchial symptoms, lung inflammation and reduced lung function.

Worldwide ambient air pollution accounts for:

  • 29% of all deaths and disease from lung cancer;
  • 17% of all deaths and disease from acute lower respiratory infection;
  • 24% of all deaths from stroke;
  • 25% of all deaths and disease from ischaemic heart disease;
  • 43% of all deaths and disease from chronic obstructive pulmonary disease.

How do you think that policies and investments supporting cleaner transport, energy-efficient housing, power generation, for example, would reduce key sources of urban outdoor air pollution?

Cooperation across sectors and at different levels – city, regional and national – is crucial to effectively address air pollution. Policies and investments supporting cleaner transport and power generation, as well as energy-efficient housing and municipal waste management can reduce key sources of outdoor air pollution. These interventions would not only improve health but also reduce climate pollutants and serve as a catalyst for local economic development and the promotion of healthy urban lifestyles.

Some of the key sector-based health-enhancing strategies against air pollution include:

  • Prioritising rapid urban transit, walking and cycling networks in cities, as well as rail interurban freight and passenger travel;
  • Shifting to cleaner heavy-duty diesel vehicles and low-emissions vehicles and fuels, including fuels with reduced sulphur content;
  • Creating green spaces that help remove PM and reduce the heat island effect;
  • Improving urban waste management, including the capture of methane gas emitted from waste sites as an alternative to incineration;
  • Replacing traditional household solid fuel with lower emission cook stoves and/or cleaner fuels;
  • Shifting away kerosene and;
  • Improving the energy efficiency of homes and commercial buildings through insulation and passive design principles, such as natural ventilation and lighting.

Tell us about how the WHO Member States have adopted a resolution and a roadmap for an enhanced global response to the adverse health effects of air pollution?

In 2015, for the first time, the World Health Assembly (WHA) unanimously adopted a resolution to accelerate global action to address household air pollution. The following year, the WHA adopted a “Roadmap for Enhanced Action”, calling for increased cross-sector cooperation to address the health risks of air pollution.

This roadmap set out a practical course for implementing the resolution, through building the knowledge base, strengthening institutional capacity, improving monitoring and reporting, and emphasising global leadership and coordination. It focuses on four priority areas of action:

  • Expanding the knowledge base about the impacts of air pollution on health;
  • Monitoring and reporting on health trends and progress towards the air pollution-related targets of the Sustainable Development Goals;
  • Leveraging the health sector to raise awareness of health benefits from air pollution reduction measures;
  • Enhancing the health sector’s capacity to work with other sectors and at all levels – local, national, regional and global – to help address the adverse health effects of air pollution through training, guidelines and national action plans.

Finally, when it comes to WHO’s response to air pollution, what are your priorities? For example, tell us about the detailed health-related assessments of different types of air pollutants, including particulates and black carbon particles, ozone, etc that you create.

In 2017, WHO Africa Region adopted a regional strategy for the management of environmental determinants of human health. The strategy outlines priorities for tackling the burden of air pollution in a comprehensive manner in countries from 2017-2021. Priority activities include:

  • Supporting national legislation and regulatory instruments on public health, including harmonisation and implementation of legislation to promote the use of clean energy sources for cooking, heating and lighting.
  • Promoting access to sustainable and clean/renewable energy in healthcare facilities, and enhancing sustainable urban policies in energy, transport, waste management and industry in order to reduce the emission of short-lived climate pollutants;
  • Promoting air pollution monitoring and consolidating evidence on its impact on human health, in line with resolution WHA68.822 and SDGs 7 and 11.5

Is there anything you would like to add?

It is imperative to also incorporate the economic angle, in particular, the hidden and visible costs of doing nothing or little to address air pollution. Economic analysis shows that health-enhancing preventive strategies for tackling air pollution could pay themselves in Africa. The World Bank estimates that air pollution cost Sub-Saharan Africa 3.8% of gross domestic product growth in 2013, around $114 billion. These health-driven expenses are expected to grow faster than GDP if nothing is done. Air pollution is leading to more days spent in the hospital and out of the workforce. Just the cost of lost labour in the region from air pollution exposure is about $6.8 billion – on a per capita basis, it is the highest in the world.

Given the growing burden of diseases associated with air pollution, African countries will need to step up efforts including mobilising domestic resources. The International Energy Agency estimates that ensuring universal access to cleaner and healthier cooking fuels in Sub-Saharan Africa by 2030 would cost $1.7 billion annually. While this would be a substantial investment, it could easily be covered by a decrease in fossil fuel subsidies in countries, which in 2015, was estimated at $26 billion in the region.

  1. Ambient air pollution: a global assessment of exposure and burden of disease, second edition. Geneva: World Health Organization; in press. [is cited in Children and AP doc] WHO Global Health Observatory, Air pollution.


Charles Ndika Akong

Technical Officer


Dr Magaran Bagayoko

Senior Scientist


WHO Regional Office for Africa (AFRO)

The World Health Organization (WHO)

Tel: +(47 241) 39402





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