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Context: Challenges and opportunities

From pollution to solution in Africa's cities: The case for investing in air pollution and climate change together

Many of Africa’s cities are experiencing exponential growth. This brings huge opportunities if the continent can overcome significant structural challenges which are caused by, contribute to and exacerbate the twin threats of air pollution and climate change. 

Rather than seeing air pollution and climate change as consequences of fossil-fuel dependent development, cities should embrace a new model of green growth. Reducing air pollution and tackling climate change by transitioning off fossil fuels should be seen as a positive economic opportunity. 

This study presents the economic case for action on clean air and climate by mapping out what this would look like for some key cities. It builds on existing research to highlight the need for and potential of joined-up action against air pollution and climate change.  

The global impact of air pollution – and the opportunities of fixing it 

Air pollution is often described as the ‘silent killer’, because it does great damage but gets little attention from funders, policy makers and political leaders. Globally, air pollution is responsible for 1 in 9 deaths, ranking as the 4th highest risk factor to health. It is the world’s leading environmental cause of illness and premature death

As with climate change, fossil fuels are a major culprit. In 2019, fossil fuel combustion (including coal, oil and gas) contributed to 1.05 million deaths – equating to over a quarter of all deaths from outdoor PM 2.5. This causes and exacerbates illnesses including lung cancer, heart disease, stroke, diabetes, pneumonia, respiratory disease and neonatal disorders. Greenhouse gases often come from the same sources as PM2.5, such as coal-fired power plants, heavy industry and diesel-fuelled vehicles. So the causes and consequences of our climate, air pollution and health challenges are connected. 

But the opportunities for joined-up action are being missed. From 2015-2021, governments gave less than 1% of their aid budgets to projects tackling outdoor air pollution around the world, while pumping four times as much into projects that prolong fossil fuel use. Reversing this approach would reduce greenhouse gas emissions, improve public health and provide economic benefits.

The human, economic and environmental cost of air pollution across Africa

The African continent endures some of the worst air pollution in the world, with high exposure in urban and rural settings throughout (see map). In 2019, a stark five of the world’s 10 most heavily polluted countries (in terms of fine particulate matter) are found in Africa (The State of Air Quality and Health Impacts in Africa). 

The consequences for public health are already severe. In 2019, air pollution killed more people in Africa than HIV/AIDS and malaria combined, contributing to 1.1 million deaths. 63% of those were linked to indoor air pollution from burning solid fuels – coal, charcoal, wood – for cooking and heating. (The State of Air Quality and Health Impacts in Africa). 

Today, the absolute number of deaths attributed to household pollution is declining thanks to a gradual transition to cleaner fuels. However, deaths attributable to outdoor air pollution are rising, because of rapid population growth, urbanisation, and industrial expansion. Without further policy interventions, “air pollution is projected to get worse” and will have a profound effect on public health, according to the Africa integrated assessment of air pollution and climate change report by the Climate and Clean Air Coalition.

The heaviest cost of air pollution across Africa is borne by those whose health suffers the most, but there are serious economic impacts too. An unhealthy population damages individual livelihoods, national budgets, the public sector and private enterprise.

There are significant environmental costs too. Some air pollutants both contribute to and worsen the impacts of climate change. For instance, black carbon (soot), a component of PM2.5 produced by incomplete burning of fossil fuels, is a significant source of pollution in Africa. It is a significant contributor to global warming

Air pollution also threatens food production, biodiversity, ecosystems and infrastructure. For example, burning coal releases dangerous gases that can poison plants, contaminate water and produce acid rain, as is often experienced in South Africa.

Without action to tackle air pollution, progress towards the goals of flagship international development frameworks will continue to falter, even with positive GDP trajectories in many African countries. Clean air is not a named goal of the African Union’s Agenda 2063, the UN’s Agenda 2030 for Sustainable Development or the UNFCCC’s Paris agreements. But it is critical to achieving most of their targets, including those relating to health, cities, environmental sustainability, industrialisation, inequality and climate change. 

Overall, cleaning the air and tackling climate change as Africa’s cities grow should be seen as much more than damage limitation exercises. By shifting from simply managing the costs of air pollution to using clean air policies as catalysts for sustainable growth, policy-makers can position their economies to thrive in a low carbon future. 

Structural challenges facing Africa’s city economies

Africa is a continent of diverse countries and cities. Each of these contexts generates different sources of air pollution that require a unique set of policy approaches. Cities also face multiple other environmental, social and economic challenges in addition to air pollution. 

Nevertheless, Africa’s urban economies face common structural challenges, and action needs to be taken if they are to grow sustainably and healthily. Proactive planning is crucial for weaning these economies off fossil fuels; without it, rapid urbanisation will lead to dramatic increases in air pollution, congestion, public service disruption, and social disintegration.

Many African countries rank among the most unequal in the world. Global poverty is becoming more concentrated on the continent, and increasingly in middle-income, urbanising countries. Nigeria, for example, recently overtook India as the country with the world’s largest poverty headcount. 

Air pollution reflects and exacerbates such structural inequalities. Death rates from air pollution are four times higher in low and lower-middle income countries than high income countries. Within each country, the poor and vulnerable suffer the most as air pollution is likely to be more concentrated where communities of low socio-economic status live. In most African countries, while the wealthy cannot completely avoid toxic air, it is more concentrated in poorer urban and rural communities.

In the poorest urban areas, residents tend to earn a living in the informal sector and are often more exposed to toxic air as a result. From vendors in Accra’s open-air Makola Market, Nairobi’s Kibera slum, or Cairo’s Tahrir Square, to street hawkers hustling at traffic lights on Lagos’, Johannesburg’s and Yaoundé’s dusty unpaved roads, informal work can have serious health consequences. 

Air pollution mirrors and amplifies other injustices. Women and children, particularly those under five, bear the greatest burden of its health impacts. Evidence shows links between exposure to air pollution in early life and lower Intelligence Quotient (IQ), impaired cognitive ability and increased risk of premature death, as well as a wider range of chronic diseases in adulthood such as cardiovascular disease, lung cancer and dementia.

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Despite what we know of the broad outcomes, localised air quality data and understanding of the problem is very poor. UNICEF has shown that only 6% of children in Africa, compared to 72% of children across Europe and North America, live near a reliable air quality monitoring station. This means the true extent of the problem and its impacts is likely to be far greater than known – and likewise that the benefits of action will be greater.   

The transition to low carbon technology and production is not happening fast enough to meet cities’ energy demands, but the basic economic calculations are changing quickly. Research finds that renewable energy is a cheaper option than fossil fuels, and could save the world as much as $12tn by 2050. Africa could be at the forefront of renewable energy generation via solar power, which can drive its own and global prosperity (IRENA). Cities that plan for this future will thrive.

Achieving this transition will require significant public and private investment, which is a major obstacle for many African countries. Many government treasuries are in, or at high risk of, debt distress, particularly following the pandemic, while overseas aid budgets are under intense scrutiny in many donor countries.

Air pollution is massively underfunded relative to the damage it does. In the cities studied, air pollution is the top cause of death. Yet Africa receives just 5% of global air quality funding, despite accounting for 26% of all global deaths from outdoor air pollution. Funding for tackling air quality and climate together is even scarcer still, accounting for just 0.02% of the region’s total climate finance.

Cleaner air and lower emissions as catalysts for Africa’s rise

Urbanisation, population growth and industrialisation are happening fast in Africa. Lagos, Kinshasa, and Cairo are already defined as megacities – urban centres of over 10 million people. Johannesburg, Nairobi, Dar es Salaam and others look set to join them within a generation. Accra and Yaoundé are among Africa’s fastest growing cities, expected to have 9.6 million and 8 million inhabitants by 2050, respectively. 

Despite the structural economic challenges described above, many African countries have numerous advantages that can deliver inclusive prosperity and eradicate poverty. Africa is the only region with a growing labour force and marked ‘youth bulge’. Alongside a steadily growing urban middle-class, this provides a demographic dividend to drive a new development path. Alongside its abundant land and natural resources, the continent is rich in renewable energy sources, though many of them remain heavily underutilised.

Half of the continent’s key economic sectors (agriculture and agro-processing, manufacturing, oil and gas, and infrastructure and construction) are heavily carbon intensive and polluting. The other half (including tourism, information and communication technology, finance and banking and consumer markets) are predicted to see fast growth over the next five years and would benefit from cleaner air through greater external investment, higher productivity and lower welfare costs. 

However, this potential is being hampered, in part because too few decisions on growth and climate change action take into account the additional financial benefits of cleaner air. Climate actions with the potential for wide-ranging benefits are often considered too costly from a narrow perspective of emissions reduction alone, and thus overlooked. 

The Climate and Clean Air Coalition recently led important work to support developing countries in addressing this via cross-cutting approaches in their Nationally Determined Contributions (NDCs). Such strategies need to be proactively supported and replicated by international funders and governments. 

In cities, the benefits of this dual approach are particularly pronounced. C40 Cities, a global collective of cities pushing for climate action, has shown that if all cities in its network achieved clean transport, buildings and industry, alongside a decarbonised grid, greenhouse gas emissions would fall by 87% on average, while PM2.5 concentrations would fall by 49% on average. 

With fast growing young populations, action taken now to curb air pollution alongside climate change in Africa’s biggest cities will reduce premature deaths and the burden of disease across future generations. The best time to do this is before a spike in population growth and industrial expansion, thus avoiding the harm and costs seen in high-income and emerging economies experiencing urbanisation, dense traffic and heavy industry.

Such interventions would primarily benefit disadvantaged populations, since they are the hardest hit by air pollution in growing cities. The improved health and economic outcomes would in turn enhance the resilience of populations and their social infrastructure, providing the foundations for sustained and inclusive growth. Following the focus on air pollution at major recent summits (e.g. Africa Climate Weeks and COPs), leaders are gradually realising that the benefits of concerted action on clean air in African cities will be counted in reduced deaths, financial savings accrued and carbon emissions reduced.

Which clean air measures did we choose?

Five indicative clean air interventions were chosen to give a sense of what is possible. These interventions – road traffic, household energy, industrial activities, land clearing and waste burning – were selected because they address key sources of air pollution in the six cities while at the same time reducing GHG emissions. Importantly, they are also likely to be feasible in the selected cities, although their effectiveness will vary (see findings). They are deliberately high-level, to account for differing contexts and needs. There is much more detail on the situation in each of our chosen megacities below here. The clean air policies are: 

  • Strengthening public transport infrastructure to deliver a 25% reduction in gasoline and diesel fuel road traffic; 
  • Deploying clean cooking appliances and alternative fuel sources, to directly reduce household air pollution, and indirectly reduce ambient air pollution;
  • Switching to cleaner sources of energy for industry to reduce harmful emissions;
  • Implementing support systems to switch from slash-and-burn to sustainable land-clearing practices;
  • Implementing waste management systems that improve collection, prevent open burning and improve incineration practices.

We have focused on the cities of Accra in Ghana, Cairo in Egypt, Johannesburg in South Africa, Lagos in Nigeria, Nairobi in Kenya, and Yaoundé in Cameroon. All six are financial, political, or economic capitals as well as major international transport hubs, and four are capital cities: Accra, Cairo, Nairobi, and Yaoundé. They were chosen because clean air measures were likely to have a direct impact and give an indication of what is possible elsewhere. 

These cities are also all in countries with some of the highest number of deaths linked to PM2.5 across Africa in 2019. (see page 19 of The State of Air Quality and Health Impacts in Africa).

The study does not model the relationships between emissions, concentrations, exposure and impacts in the same way as a typical impact assessment study. Instead, it draws on parameters and relationships established in existing literature and expert interviews, to give a “business-as-usual” (BAU) and “improved air quality” (IAQ) scenario. It then compares the estimated impact in terms of premature deaths, costs incurred, and greenhouse gases emitted in each scenario, via the following steps:

  1. For the business-as-usual scenario, the impact of air pollution on premature mortality and lost days of work (absenteeism) is estimated up to 2040 by assuming trends from previous years continue in line with economic growth.   
  2. The financial costs associated with this scenario are then calculated by applying the discounted economic value of healthy life years lost due to premature mortality and disability across the whole time period as cities grow.
  3. The benefits of the improved air quality scenario are estimated by applying the projected improvements in PM2.5 concentration levels from the implementation of five clean air measures and translating this into corresponding reductions in premature deaths and years lost to disability from the BAU across the time period.
  4. Then, following the same method as the BAU in step 2, the financial cost of this alternative future scenario (IAQ) is estimated, as are the greenhouse gas emission reductions associated with each measure.

In this way, the study quantifies the comparative benefits (health, financial and climate) associated with each scenario in each city. See here for a more detailed description of our methodology

This research is far from exhaustive, in part because an exhaustive analysis would be impossible for many reasons. Not least among these reasons is the fact that only 7 of 54 African countries have reliable, accessible regulatory grade real-time air pollution monitors as of 2019. 

Nonetheless it provides first-of-their-kind estimates for each city based on the available information. These estimates are intended to provide a sense of potential scale rather than an investment case. The study represents an initial step towards the more in-depth and targeted analyses that are needed to robustly quantify air quality and its impacts across Africa following best-practice modelling approaches.

There are a number of important caveats, many of which point to the true impacts being higher, and the need for further research and investment:

  1. We omit major known impacts of air pollution, such as loss of productivity at work (presenteeism), healthcare costs, and impact on crop yields. These will all be substantial, resulting in health and economic impacts higher than shown.
  2. We focus on only PM2.5 as the primary driver of mortality and morbidity. It does not account for the wider range of air pollutants which harm human health such as PM10 and nitrogen dioxide, among others.
  3. Specific measures and action plans will differ from one city to another, and policy design and action should be formulated on the basis of an integrated framework, (see recommendations).
  4. The primary estimates are based on formal sector data analysis, and do not include GDP estimates of the informal economy. The informal economy’s contribution to GDP would increase economic value by 30-60% of the 2019 figures, to more than double by 2040, and would provide a more realistic representation of the health, economic and financial costs in these cities. However, the study acknowledges the absence of good quality available data – additional direct primary research is needed to accurately measure the numbers involved in the informal sector and its impact on this issue.
  5. To overcome city-level data gaps, this study scales down country-level data based on metropolitan area populations and estimates of city GDP as required. Scaling from country data to city data most likely underestimates health effects from air pollution in cities, although relationship is unclear. It also relies on extrapolations from existing studies and data points from other countries given limited to no primary research in some African contexts. The results have been scrutinised through expert interviews, but are indicative and underline the need for better city-level data gathering and analysis. 

Several other key assumptions and simplifications of the analysis can be found in the annex detailing our methods and approach.

Go to next section: 2. Findings: costs to people, economies and climate

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