Africa has an air pollution problem – but lacks the data to tackle it

Another smoggy day in Abidjan. Image: Getty.

The World Health Organisation (WHO) recently launched BreatheLife, a campaign to make people more aware about the fact that air pollution – which it calls the invisible killer – is a major health and climate risk.

“Invisible” may refer to the lack of awareness that air pollution is a major health risk. In fact, air pollution levels exceeding the WHO air quality guidelines are often very visible, particularly in developing countries. This is especially true for billions of people living in close contact with air pollution sources. Those who, for example, cook on inefficient stoves with fuels such as coal. Or live in an industrial area.

The WHO has air quality programmes for most of the world’s regions. These review the effects of air pollution on health and help countries develop sustainable air quality policies. But none exists for sub-Saharan Africa. It is not clear why. A possible explanation may be that environmental health risk factors are overshadowed by other risks like malnutrition, HIV, tuberculosis and malaria.

Despite this, we do know something about the continent’s air pollution levels. In the first major attempt to estimate the health and economic costs of air pollution in Africa, an Organisation for Economic Co-operation and Development report found that air pollution in Africa already causes more premature deaths than unsafe water or childhood malnutrition. It warned that this could develop into a health and climate crisis.

But how bad are air pollution levels in Africa? Which countries have the worst air pollution levels? What are the main sources and drivers of air pollution? Are the main sources and drivers of air pollution different from those on other continents?

The answers to these questions are severely hampered by a lack of data as well as poor regulation and laws in African countries. The only country on the continent that has ambient air quality standards enforced by air quality laws and regulations is South Africa. Other countries have either ambient air quality standards or air quality laws and regulations, or none at all.

What’s known

Air pollution is a complex mixture of many components.

The WHO’s air quality guidelines, as well as country-specific laws, have identified a few air pollutant components: particulate matter smaller than 2.5 micrometer (PM2.5) and 10 micrometer (PM10) in aerodynamic diameter, sulphur dioxide (SO2), ground-level ozone (O3), carbon monoxide (CO), benzene, lead and nitrogen dioxide (NO2).

The most dangerous are PM2.5 and ultrafine particles (UFP); the latter are smaller than 100 nanometer in aerodynamic diameter. PM2.5 and UFP penetrate deeper into the lung alveoli and may pass into the bloodstream. PM10 and PM2.5 are important indicators of long-term air quality and of health risks.

Based on data of ground measurements conducted in 2008-2015, Africa’s PM10 levels are not the highest in the world.

The database is the largest of its kind and covers over 3,000 human settlements – mostly cities – in 103 countries. The number one spot belongs to the Eastern Mediterranean region, followed by the South-East Asia region and then Africa. But the WHO acknowledges numerous limitations to the data sources. Fewer sites globally measure PM2.5, hence the focus is on PM10.

The PM2.5 data based on the WHO air quality model show that the number one spot again belongs to the Eastern Mediterranean region, followed by the South-East Asia region and then Africa. Given the lack of PM2.5 ground measurements in Africa, the PM2.5 data derived from the WHO air quality model for Africa should be viewed with caution.


Where is the air worse in Africa?

It is hard to say what the real picture is. The modelled PM2.5 data supplements the data from ground monitoring networks, especially in regions with no or very little monitoring, as is the case in Africa.

The PM10 data, based on ground measurements conducted between 2008 and 2015, show that all African countries with PM10 data exceeded the WHO annual guideline of 20 microgram/cubic meter (µg/m³).

Onitsha in Nigeria had the highest yearly PM10 level of 594 µg/m³ globally, nearly 30 times higher than the WHO annual guideline. But the quality of the data is questionable. The level for Onitsha is based on PM10 data collected only in 2009 and only at one site. The database also does not mention on how many days the 2009 yearly level is based as missing data can lead to a distorted yearly level. The lowest yearly PM10 level was recorded at Midlands in Mauritius (20 µg/m³). But this is based only on 2011 data collected again at only one site without mention of how many days in 2011 were measured.

It is also difficult to know exactly what the contribution of different sources of air pollution are in Africa.

The amount of air pollution in any given location is affected by a combination of local, regional and distant sources. It is also affected by the dispersion of pollutants, which in turn depends on numerous weather conditions such as wind direction, temperature and precipitation.

A recent review indicated that very few studies in Africa conducted source apportionment of PM2.5 and PM10. The review concluded that (based on the few studies) 17 per cent, 10 per cent, 34 per cent, 17 per cent and 22 per cent of PM2.5 levels in Africa are due to traffic, industry, domestic fuel burning, unspecified source of human origin and natural sources - such as dust and sea salt. For PM10 the corresponding source distribution is 34 per cent, 6 per cent, 21 per cent, 14 per cent and 25 per cent, but should be viewed with caution due to the few studies.

Based on the limited number of PM10 and PM2.5 source apportionment studies in Africa, these tentative conclusions can be drawn. Traffic is a major source of PM10 levels in Africa as in many other global regions. The other two major sources of PM10 in Africa are domestic fuel burning and natural sources. In other regions of the world, industry and the ambiguous “unspecified source of human origin” contribute more.

Domestic fuel burning is the major source of PM2.5 in Africa, followed by traffic and natural sources such as dust. In other regions of the world, traffic, industry and the ambiguous “unspecified source of human origin” contribute more to PM2.5 levels.

Air quality interventions

Regardless of the exact global source contributions, the main sources of air pollution should be tackled globally in management plans and interventions.

Obvious interventions include clean energy technology such as solar power, to minimise domestic fuel burning and emissions from coal-fired power plants. Other initiatives include clean public transport, bicycle lanes to cut traffic emissions, recycling and controls on industrial emissions.

Air pollution does not stop at country or continental borders. It is a major risk factor for climate change. A disregard for air pollution levels in Africa may have a major impact on global climate change in the years to come.The Conversation

Janine Wichmann is associate professor at the University of Pretoria.

This article was originally published on The Conversation. Read the original article.

 
 
 
 

Where actually is South London?

TFW Stephen Bush tells you that Chelsea is a South London team. Image: Getty.

To the casual observer, this may not seem like a particularly contentious question: isn’t it just everything ‘under’ the Thames when you look at the map? But despite this, some people will insist that places like Fulham, clearly north of the river, are in South London. Why?

Here are nine ways of defining South London.

The Thames

Image: Google Maps/CityMetric.

It’s a curvy river, the Thames. Hampton Court Palace, which is on the north bank of the river, is miles south of the London Eye, on the south bank. If the river forms a hard border between North and South Londons, then logically sometimes North London is going to be south of South London, which is, to be fair, confusing. But how else could we do it?

Latitude

You could just draw a horizontal line across a central point (say, Charing Cross, where the road distances are measured from). While this solves the London Eye/Hampton Court problem, this puts Thamesmead in North London, and Shepherd’s Bush in South London, which doesn’t seem right either.

Image: Google Maps/CityMetric.

And if you tried to use longitude to define West and East London on top of this, nothing would ever make sense ever again.

The Post Office

Image: Wikimedia Commons.

Some people give the Post Office the deciding vote, arguing that North and South London are defined by their postcodes. This does have some advantages, such as removing many contentious areas from the debate because they’re either in the West, East or Central postcode divisions, or ignoring Croydon.

But six of the SW postcodes are north of the river Thames, so we’re back to saying places like Fulham and Chelsea are in south London. Which is apparently fine with some people, but are we also going to concede that Big Ben and Buckingham Palace are South London landmarks?

Taken to the extreme this argument denies that South London exists at all. The South postcode region was abolished in 1868, to be merged into the SE and SW regions. The S postcode area is now Sheffield. So is Sheffield in South London, postcode truthers? Is that what you want?

Transport for London

Image: TfL.

At first glance TfL might not appear to have anything to add to the debate. The transport zones are about distance from the centre rather than compass point. And the Northern Line runs all the way through both North and South London, so maybe they’re just confused about the entire concept of directions.

 

Image: TfL.

But their website does provide bus maps that divide the city into 5 regions: North East, South East, South West, North West and the Centre. Although this unusual approach is roughly speaking achieved by drawing lines across and down the middle, then a box around the central London, there are some inconsistencies. Parts of Fulham are called for the South West region, yet the whole of the Isle of Dogs is now in North East London? Sick. It’s sick.

The Boundary Commission

One group of people who ought to know a thing or two about boundaries is the Boundary Commission for England. When coming up with proposals for reforming parliamentary constituencies in 2011, it first had to define ‘sub-regions’ for London.

Initially it suggested three – South, North East, and a combined North, West and Central region, which included Richmond (controversial!) – before merging the latter two into ‘North’ and shifting Richmond back to the South.

In the most recent proposal the regions have reverted to North Thames and South Thames (splitting Richmond), landing us right back where we started. Thanks a bunch, boundary commission.

The London Plan

Image: Greater London Authority.

What does the Mayor of London have to say? His office issues a London Plan, which divides London into five parts. Currently ‘South’ includes only Bromley, Croydon, Kingston upon Thames, Merton, Sutton, and Wandsworth, while the ‘North’ consists of just Barnet, Enfield, and Haringey. Everywhere else is divvied into East, South or Central.

While this minimalist approach does have the appeal of satisfying no-one, given the scheme has been completely revised twice since 2004 it does carry the risk of seismic upheaval. What if Sadiq gets drunk on power and declares that Islington is in East London? What then?

Wikipedia

 

Image: Wikimedia Commons/CityMetric.

The coordinates listed on the South London article lead to Brockwell Park near Herne Hill, while the coordinates on the North London article lead to a garden centre near Redbridge. I don’t know what this means, so I tried to ring the garden centre to see if they had any advice on the matter. It was closed.

Pevsner Guides

Image: Wikimedia Commons/CityMetric.

Art historian Sir Nikolaus Pevsner might seem an unlikely source of help at this juncture, but we’ve tried everything else. And the series of architectural guides that he edited, The Buildings of England, originally included 2 volumes for London: “The Cities of London and Westminster”, and “everything else”. Which is useless.

But as his successors have revised his work, London has expanded to fill 6 volumes: North, North West, East, The City, Westminster, and South. South, quite sensibly, includes every borough south of the Thames, and any borough that is partly south of the Thames (i.e. Richmond). And as a bonus: West London no longer exists.

McDonald’s

I rang a McDonald’s in Fulham and asked if they were in South London. They said no.

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