Air quality in Nairobi

Where does the air pollution data for Nairobi come from?

The Nairobi air pollution data, as of September 2021, is generated entirely from low-cost PM 2.5 monitors that are deployed and operated by a number entities in Nairobi, including the Nairobi County Government, Safaricom, UNEP in addition to a number of anonymous contributors. The data is aggregated and validated by IQAir. The hourly average for each station is published and combined to an hourly city average. In the historic data, the hourly average is combined to a daily average.

How polluted is Nairobi?

Nairobi is the capital of Kenya and one of the largest cities on the African continent. It also goes by another local name of Enkare Nairobi, meaning cool water in the Maasai language, a reference to the Nairobi river that flows through the city.

Nairobi is home to some 4.3 million people within the city limits, and a further 9.3 million in the extended metropolitan area surrounding the city. Nairobi is home to many business centers and factories, making it the 4^th largest trading area within Africa. Due to these business activities and the sheer amount of people and anthropogenic activities, it is not surprising that Nairobi suffers from its share of air pollution.

The dominant pollutant type in Nairobi is PM2.5. In 2020, the average PM2.5 concentration in Nairobi was 14.7 µg/m3, which is about 1.5 times the recommend annual PM2.5 threshold concentration of the World Health Organization (WHO). The most polluted month in 2020 was July, with an average PM2.5 concentration of 22.6 µg/m3.

Generally speaking, daily air quality in Nairobi typically fluctuates between good and unhealthy levels.

What are the main causes of pollution in Nairobi?

Much of the pollution in Nairobi comes from sources related to the combustion of certain materials, and the mass movement of people and goods. A large number of vehicles, including cars, motorbikes and trucks, many of which are older and produce far more pollution than their newer counterparts would.

There is also the issue of heavy duty vehicles to consider, ones such as trucks, lorries and buses, many of which also run on older diesel engines, putting out more pollution than seen in newer models.

Other causes of pollution are factory emissions, with many reports of vulnerable demographics such as young children and pregnant mothers being affected by the industrial effluence and fumes given off by factories, lacking the more stringent regulations necessary to keep their air contaminants to a minimum.

As such, factories and industrial areas would be putting out vast amounts of dangerous pollutants, that when coupled with vehicle emissions, combine to create the two biggest sources of pollution in Nairobi.

Other minor sources would be fine particulate matter coming from construction sites and road repairs, as well as open burning taking place, particularly in areas that have little to no proper garbage disposal or collection, such as low income districts. Refuse, both organic and synthetic can be set ablaze, releasing a plethora of dangerous pollutants into the atmosphere.

What are some of the pollutants found in Nairobi?

With much of its pollution emanating from combustion sources, the types of pollutants found in the air would match these sources as expected. In areas that see high volumes of vehicular activity, pollutants such as nitrogen dioxide (NO₂) and sulfur dioxide (SO₂) would be present, as well as the formation of ozone (O₃) under the right conditions, usually as a result of the various oxides of nitrogen coalescing on the ground level, and when subject to high levels of sunlight and ultraviolet radiation (which is plentiful in Kenya), converted into ozone.

Whilst ozone is an invaluable compound in the upper atmosphere for our continued existence, when it forms on ground level as smog, it has a vast array of health issues that come along with it, which will also be discussed in short.

Other pollutants include fine particulate matter such as black carbon or finely ground silica from construction sites. Microplastics would also be found in the air, along with dangerous metals such as mercury, cadmium and lead. Volatile organic compounds (VOC's) would be found around any area that has burning or combustion taking place, some of which would include dangerous chemicals such as benzene, xylene or formaldehyde. These are a few of the many pollutants that would be found in certain high pollution areas around Nairobi.

What can Nairobi do to improve pollution levels?

Some initiatives that Nairobi could undertake to improve its pollution would be to invest more into public transport infrastructure, getting people onto public transport and other greener forms of transportation such as bicycles within the city center.

Other prominent ones would be the introduction of fines and charges to both vehicles and factories that exceed dangerous levels of pollutive output, with the eventual replacement of these vehicles with cleaner ones to reducing the amounts of haze, smog, fumes and smoke permeating the air in Nairobi. The same goes for factories, with more stringent air measuring activities taking place around their perimeters to ensure that their pollutive output does not exceed regulated amounts, with heavy fines and threats of shutdown being issued if they break these regulations.

What are some health issues associated with breathing pollution in Nairobi?

Poor air quality is at the heart of many common health issues, such as asthma. With increasing pollution levels, both the short and long term effects on health increase.

Exposure to ground level ozone can lead to rapid aging and damage to the lungs, with breathlessness, asthma attacks and overall reduced lung function all being possible, side effects that are also caused by elevated levels of nitrogen dioxide.

Air pollution is associated with increased rates of ischemic heart diseases, where the flow of blood to the heart is reduced, causing a shortage of oxygen that is needed. Poor air pollution is also associated with an increased rate of miscarriages, lower birth weight and a higher likelihood of birth defects occurring. Air pollution is also associated with lung and throat cancer, and damage to the blood vessels that can occur because fine particulate matter entering the blood stream via the lungs, wreaking havoc on the circulatory system and causing damage to the livers and kidneys, as well as affecting reproductive health.