Qualité de l’air à Addis Ababa

What is the air quality index of Addis Ababa?

Addis Ababa is the largest city and capital of Ethiopia. It is located in the Horn of Africa, towards the east of the country and according to a 2007 survey has a population of almost 2.8 million people.

Towards the end of 2020, the state of the air quality was classified as being “Moderate” according to recommendations by the World Health Organisation (WHO). The recorded figure was 76 US AQI with the main pollutant being the fine particulate matter, PM2.5 with a concentration of 24 µg/m³. The WHO states any figure up to 10 µg/m³ is their target figure, between 10 and 12 µg/m³ is classed as “Good” and 12.1 – 35.4 µg/m³ is classed as being “Moderate”.

In 2019, the average PM2.5 level was 20.1 µg/m³ which did not vary too much throughout the whole year. Previous years returned figures of 27.1 µg/m³ and 26.9 µg/m³ for the years 2018 and 2017 respectively.

What are the sources of Addis Ababa’s polluted air?

Having reviewed a few studies that have been conducted in Addis Ababa the concentration levels of the microscopic particulate matter PM2.5 was seen to be as high as 280 µg/m³. Indoor carbon monoxide (CO) was also much higher than the recommended levels for public safety. Households that used traditional biomass stoves as their preferred fuel showed an even greater level. It is thought that over 95 per cent of all households still use the traditional stove for cooking. Greatly increased numbers for carbon dioxide (CO₂) were also recorded in these houses.

The ambient PM10 level was below the WHO guideline for the majority of samples which were taken. Carbon monoxide (CO) levels taken at random at the roadside throughout the city were also lower than expected, even though the annual increase in car ownership is rising on average by 9 per cent per annum.

The tentative conclusion based on the results of these studies indicates a lack of real-time permanent monitoring stations where an accurate figure can be obtained on a regular basis.

Is air pollution in Addis Ababa getting worse?

Air pollution is a challenging problem in both Low and Middle-Income Countries (LMIC) and non-LMIC settings, with significant variations between the two in terms of sources and scale. In non-LMICs, air pollution arises mainly from industrial and motor vehicle sources because households use clean fuel/energy source for cooking and heating, very often electricity or LPG.

The high number of long-term monitoring stations, together with the trained manpower to operate them and analyse the data has caused recommended guidelines to be biased. The recommended figures do not reflect the situation in LMICs. The resulting figures were then quoted by regulatory bodies and also by the World Health Organisation (WHO).

Air pollution is compounded in LMICs because of the traditional use of solid biomass and adulterated liquid fuels. Cheap hydrocarbons are often mixed with more expensive liquid fuels to make them last longer. These toxic fuels are used in houses where women and children spend more time than men. The total lack of a constant source of data gives the local governments no choice but to use data from external sources which is not reflective of their own situation.

What can be done to improve the air quality in Addis Ababa?

Indoor Air Pollution (IAP) has been studied far more than outdoor pollution in cities such as Addis Ababa. Many studies based their findings on the type of fuel used for cooking and not from actual figures obtained through measurements. They looked for PM2.5, nitrogen dioxide (NO₂), polyaromatic hydrocarbon (PAH), carbon monoxide (CO) and sulphur dioxide (SO₂).

In 2012, measurements were taken in 59 homes in slum neighbourhoods for a period of 24 hours. The average figure for PM2.5 was 1,134 µg/m³ which came from houses that primarily used solid biomass as its main fuel source. Those using kerosene and clean fuel returned figures of 636 µg/m³ and 335 µg/m³, respectively.

An initial study carried out in the Oromia Region, compared levels of PM particles in homes that do/do not use biomass fuels for cooking. The study noted that concentrations of respiratory suspended particulates (RSP) in homes that used biomass were 130 times higher than the suggested air quality standards. This indicates a serious risk to public health.

Yet another initial study was conducted in 10 homes in Addis Ababa which focused on the inhalation of the smoke produced from roasted coffee beans during a traditional ceremony. The study showed high PM exposure, with an average PM concentration of >1000 µg/m³. This traditional coffee ceremony, which involves inhaling the smoke of roasting coffee beans, is a short but recurring household activity, happening between 2 and 3 times each day.

What are the effects on health through breathing in Addis Ababa’s polluted air?

Nitrogen dioxide (NO₂) was the only pollutant measured every three months over a 24-hour period for over two years in 3,000 rural households that have under-5-year-olds living there. The average annual concentration of carbon dioxide was found to be 97 µg/m³ which is over twice as high as the recommended levels as suggested by the WHO.

A similar study was conducted in 54 Addis Ababa homes to measure their levels of carbon monoxide (CO). Over a period of 8 hours, the average level of carbon monoxide was found to be 16 parts per million which is almost twice the suggested level of 9 ppm. These figures were obtained from homes without ventilation in their kitchen. This figure dropped considerably for homes which had chimneys where figures of just 5 ppm were discovered. In rural Tigray levels of 44 ppm were recorded. However, when dried dung is used as a fuel source the carbon monoxide level spikes at 4,000 ppm.

A survey was instigated in Addis Ababa and Kebribeyah which compared levels of PM2.5 and carbon monoxide (CO) before and after an intervention that substituted ethanol for kerosene fuels. In Addis Ababa, the average reduction of PM2.5 was 64 per cent and 76 per cent for carbon monoxide. Similar findings were observed in Kebribeyah with a 94 per cent reduction in PM2.5 and a 72 per cent reduction in carbon monoxide.