The invisible silent killer in Eastlands

Air pollution is responsible for seven million deaths globally every year, with 600,000 of these occurring in Africa

In Summary

• Residents around Dandora dumpsite are exposed to high concentrations of both PM2.5 and PM10.

• This can result in health problems, such as respiratory illnesses, with children worst-hit.

A boy sits on Dandora garbage/ FILE
A boy sits on Dandora garbage/ FILE

It is 3 pm on a weekday afternoon. We are surrounded by pungent odours from decomposing garbage, and the air is thick with steam and smoke. The heavy, nauseating smell permeates everywhere, even through the dust masks we have on.

We are in Dandora, an estate established in 1977 to offer high-quality affordable housing as part of a project partially financed by the World Bank.

However, the area has since become home to East Africa’s largest dumpsite, a 32-acre land covered with thousands of tonnes of garbage, where more than 3,000 people eke out a living.


The dumpsite was once a quarry that the City Cou  ncil of Nairobi sought to use temporarily for waste disposal in the 1970s. But 40 years on, trucks continue to trundle in, dumping at least 2,000 tonnes of waste every day.

Njoroge Kimani, a biochemist and lead researcher in a 2007 study commissioned by Unep, described the dumpsite as a big health problem for residents of Dandora, Korogocho, Babadogo and Kariobangi North, especially as waste from the dump continues to taint their water supply, and smoke from burning garbage affects the air they breathe.

As it turns out, the smoke and the fumes have made Dandora a hot spot for respiratory illnesses, with children exposed to levels of air pollution far higher than what is considered healthy. Residents go about their business despite the risks.

As we continue our visit, a kindergarten pupil wearing the uniform of the nearby New Testament Centre is heading home from school.

She stares at our mask-covered faces for a moment, bites the peeled mango in her left hand and walks away, seemingly oblivious to the stale air that hangs low over the dumpsite.

She quickly disappears into the sprawling slum at the edge of the dumpsite that many call home.


Exposure to high concentrations of both PM2.5 and PM10 can result in a number of health impacts, ranging from coughing and wheezing to asthma attacks, pneumonia, bronchitis, high blood pressure, heart attack, strokes and premature death.



To measure the air quality around the Dandora dumpsite, we collected data using low-cost mobile air quality sensors, which are part of Code for Africa’s sensors.AFRICA initiative.

The air quality sensors collect data on concentrations of particulate matter. Particulate matter is a mixture of solid particles and liquid droplets that are found in the air.

Some particles (PM10 ), such as dust, dirt, soot, or smoke, are large or dark enough to be seen with the naked eye. Others are so small (PM2.5 ) that they can only be detected using an electron microscope.

The PM2.5 particulate matter is so small that once you breathe in, they can cross from your lungs into the bloodstream, where they can seriously impact on your health.

The dust, dirt, soot and smoke (PM10 ) are highest during the day and are clearly visible. But the fine particles, mainly from soot and volatile organic compounds (PM2.5 ), are most common at night, which is when the garbage is set on fire.

Most PM10 particles will settle down eight hours after becoming airborne, while PM2.5 particles take at least 36 hours to settle.

Picture this: a human hair is 100 µm thick. This means PM10 particles are 10 times smaller than human hair, while PM2.5 particles are a quarter of the size of PM10 particles. For comparison, a pollen grain is estimated to be 6µm wide.

The World Health Organisation (WHO) recommends maximum levels for fine particulate matter (PM10 ) at 50 micrograms per cubic metre on average over a 24 hour period. The mean PM10 in the area is over three times the recommended rate.

PM10 concentration is highest in the residential areas around Dandora dumpsite. These include Dandora police station, where we recorded a reading of 285.23, Friends School Dandora, 44.85 and Korogocho, 44.08. It is lowest in Kariobangi North, where it was recorded at 23.87.

The latest Kenya Demographic Health Survey shows that since 2015, pneumonia and not malaria is the leading cause of death. Total deaths due to pneumonia in 2016 were 21,295, representing 11.5 per cent of total registered deaths. Other major causes are cancer, HIV-Aids, anaemia, heart disease and tuberculosis.

The disease, according to Health ministry, accounts for 16 per cent of the deaths among children under five.

According to a recent study done by Kenya Medical Research Institute (Kemri), the rate of children who die under the age of five still remains high, with respiratory tract infections leading followed by diarrhoea and malnutrition.  

The risk of childhood mortality in the slums of Nairobi is high between May and July, increasing significantly by about 50 per cent compared to the rate of death between October and December. This is the period of the long rains and the onset of the cold season.

Tropical Medicine and International Health in 2007 investigated the seasonal pattern of overall mortality. The journal studied children aged below five living in informal settlements in Nairobi. It ranked Korogocho, which is close to the Dandora dumpsite, as high risk, compared to 15 other slums including Kibra.

According to the study, medical records obtained from the Catholic Church dispensary at Kariobangi showed that an average of 9,121 people were treated for respiratory tract-related problems in 2003-2006.


Another survey conducted in 2018 by Researchgate indicates an urgent need to take effective actions to reduce air pollution levels and improve the situation and health for residents of Nairobi’s informal settlements.

The semi-ecological study among children under five from Korogocho and Viwandani slums and exposure measurements of particulate matter (PM2.5) at the village level were aligned to data from a retrospective cohort study design.

Researchers used logistic and poisson regression models to ascertain the associations between PM2.5 exposure level and child morbidity and mortality.

"Our findings provide evidence regarding child health associations to fine particulate matter concentrations," the research read.

"It should be seriously considered by professionals and policymakers when designing policies and strategies to reduce the burden of disease among children in rapidly developing urban areas of Africa."

In recognition of the challenges that environmental factors, such as poor air, pose to human health, Unep has termed air pollution an invisible silent killer. It is responsible for seven million deaths globally every year, with 600,000 of these occurring in Africa.

‘Apart from PM10, which is extremely hazardous, the primary component of fine particle air pollution (PM2.5 ) contributes to a number of adverse health effects, including asthma, low birth weights, heart attacks and lung cancer," Unep said.

The mean PM10 for those regions stands at 154.5 micrograms, three times higher than the recommended maximum level by the World Health Organisation.

The region also has high levels of PM2.5, with the sensor recording a high of 33.63 micrograms in Dandora near the police station, and the lowest reading occurring near Kariobangi North Catholic Church, where the sensor showed 6.6 micrograms per cubic meter.

This translates to a mean of 20.12 micrograms compared to WHO’s recommended maximum levels of 25 micrograms per cubic metre on average over a 24hr period.

Exposure to high concentrations of both PM2.5 and PM10 can result in a number of health impacts, ranging from coughing and wheezing to asthma attacks, pneumonia, bronchitis, high blood pressure, heart attack, strokes and premature death.

This perhaps explains why the four informal settlements surrounding the dumpsite — Dandora, Korogocho, Ngomongo and Kariobangi North — have some of the highest rates of child mortality related to respiratory disorders in Nairobi.


A survey of 10 health facilities in Dandora, Korogocho and Kariobangi North revealed that at least two out of 100 infants die every year of either pneumonia or birth complications.

Pneumonia is a lung disease characterised by inflammation of the air spaces in the lungs, most commonly due to an infection. It may be caused by viral infections, bacterial infections or fungi. The most common bacteria that cause pneumonia are streptococcus pneumonia.

Air pollution can make otherwise healthy people more susceptible to pneumonia by impairing the ability of the lungs to fight off infections. In particular, exposure to air pollution increases susceptibility to acute lower respiratory infection, making the body more prone to infection and less able to fight it.

Interviews with health workers based in Dandora revealed that pneumonia was the leading cause of death, especially among children under five. They were from Paradise Health Service, New Light Medical Centre and Dandora II Health Centre, as well as a nurse from Baraka Clinic in Kariobangi North, which is in the vicinity of the dumpsite.

This story was produced in partnership with Code for Africa's iLAB data journalism programme, with support from Deutsche Welle Akademie.

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