By Joyce Chimbi
Nairobi, Kenya: The arrival of the yellow school bus signals the beginning of yet another day on the school calendar and the continuation of a child’s journey toward lifelong learning and earning opportunities. Nearly a quarter of a million children aged 6 to 13 years are in primary school within Nairobi County.
Until recently, 10-year-old Samara Wanjiru was among hundreds of thousands of children riding a school bus running on diesel engines to one of an estimated 1,241 elementary education institutions in Nairobi. But Samara has been inside a classroom as many times as she has been out due to severe respiratory complications.
“I used to have serious chest-related problems as a child. We assumed that Samara inherited her health problems from me. The girl was commuting from Nyayo Estate to a school along Ngong Road. In 2023, we moved houses. Today, her school and our house are separated by a fence and it was not until six months after the move that it dawned on us that the end of the commute aligned with the end of my daughter’s health problems,” says Imelda Wanja, parent.
Dr. George Mwaniki the Africa Head of Air Quality at the World Resources Institute (WRI) affirms that diesel-fuelled vehicles are “major sources of harmful pollutants. Besides particulate matter such as PM2.5, they also emit what we call Volatile Organic Carbons (VOCs), and some of them are known to be very serious carcinogens as they cause cancer. With the many diesel engine school buses in the morning and evening, these emissions can be quite substantial and risky for children as these buses also operate inside the schools.”
These observations are supported by Mary-Ann Teresa Amondi. The school principal says that there is a case to be made for clean energy school buses: “Children come to school in very low spirits, some sickly, others vomiting in the buses, others have a headache and we all say – they will outgrow car sickness. Others are dismissed as not wanting to go to school. But you can see a difference between children in our boarding section who have no such morning-related sicknesses and the day schoolers.”
Air Pollution fact sheet.The World Health Organisation (WHO) estimates show that 98 percent of children in low- and middle-income countries such as Kenya are exposed to ambient fine particulate matter (PM2.5) levels above WHO air quality guidelines. PM2.5 poses the greatest risk to health for they are less than 10 micrometers in diameter and can get deep into the lungs.
Dr Mwaniki states that diesel engines release black carbon which is the result of incomplete combustion of fossil fuels placing children at risk of both short-term and long-term health complications. Exposure to PM2.5 can therefore affect heart and lung function, worsening medical conditions such as heart disease, and asthma, and heightening the risk of heart attacks.
“There is indeed a very strong connection between air pollution and diesel-powered engines especially in major cities across the world. Air pollution is a major environmental health risk factor and per WHO, is responsible for approximately 7 million premature deaths annually children are the most affected as their respiratory systems are still developing and again children have a higher breathing rate compared to their body weight making them more vulnerable to exposures and effects associated with air pollution, says Sami Simiyu, a Consultant at Vital Strategies.
He says the transport sector is a major contributor to air pollution especially in a major city such as Nairobi where the transport system relies heavily on diesel-powered engines. “We have many schools which also have many buses for school transportation. Diesel-powered engines contain a complex mix of pollutants such as particulate matter, nitrogen oxide, and Sulphur dioxide.”
Simiyu says exposure to these pollutants especially PM2.5, as well as nitrogen oxide, has been associated with adverse health effects. Short-term health effects include eye, nose, and throat irritation, some seasons of coughing and sneezing, and shortness of breath. Long-term exposure can affect lung function, leading to serious and chronic health conditions. Nitrogen oxide pollutants react with the atmosphere – they are not stable and can therefore form secondary pollutants.
“With PM2.5, once it enters the blood vessels, and once in the circulatory systems, it can access all the major organs as blood moves in all the organs in the body increasing the risk of other diseases such as hypertension. The children are in these buses at high-traffic hours and the prolonged exposure to the emissions increases the risk of morbidity and mortality associated with the cardiovascular diseases related to air pollution,” he cautions.
Victor Nthusi, a Consulting Research Fellow at Health Effects Institute says that when things burn, gases and particles are released into the air. These particles are so small that we cannot see them but we breathe them in every day. This is air pollution – an urgent public health crisis.
Emphasizing that diesel engines normally produce more particulate matter compared to gasoline engines. Therefore, exposure to diesel exhaust worsens respiratory illnesses in children and can increase emergency room visits or absence from school.
“In the short term, exposure to diesel exhaust can lead to aggravation of asthma and other respiratory illnesses. In the long term, particulates have been linked to decreased lung function, delayed brain development, and stunted growth,” Nthusi expounds.
Children are highly vulnerable to air pollution. They take more breaths than adults as their young hearts and lungs work harder – their hearts beat faster as their young organs grow. Their lungs are not fully mature until the age of 20 years.
Scientific studies have also linked higher cardiovascular and respiratory hospital admissions such as those experienced by Samara, emergency department visits, and deaths from PM2.5 exposure. Nairobi-based independent researcher and consulting lecturer Eric Muchelule equates the risk of diesel air pollution to maternal smoking with air pollution.
He says, “Even worse, diesel engines cause self-pollution whereby emissions from the bus itself enter or intrude into the bus cabin where the children sit, and for the entire period of the journey, the children will be breathing very dangerously polluted air. Even those spending less than an hour inside the bus are still at risk from repeated exposure throughout the year. Children inside the bus are therefore regularly exposed to PM2.5.”
Air pollution, Muchelule stresses, is “no small matter as it is one of the leading threats to child health, accounting for almost 1 in 10 deaths in children under five years of age. Their future is also compromised because diesel engine pollution compounds effects of climate change leading to life-threatening situations such as the ongoing floods.”
Muchelule further stresses that emerging research is showing another dangerous aspect besides tailpipe emissions from exhaust fumes: “Air pollution inside a school bus can be 5 to 10 times worse than the outside environment. The level of air pollution inside the bus depends on wind speed, whether the windows are open or closed, and the condition and age of the bus. Many of the buses on the road are older than 10 years so the risk is there and highly substantial.”
Dr. Mwaniki says besides the air quality, health, and developmental benefits of transitioning to electric school buses in line with the Clean School Bus Program currently on pilot in several states in the United States, there are additional and significant cost and climate benefits.
“Most diesel engines are used to carry very heavy loads of three, four or five tonnes but when you think of a school bus, the load is very small because these are small children. You do not therefore need such a heavy engine to transport children. In Kenya, for every six shillings you use on a diesel engine, in electric buses you only use one shilling and the buses can charge during the day when not in use or at night. The case for saving money is quite strong as the cost of maintaining electric buses is 60 percent less,” Dr. Mwaniki expounds.
He says that although electric buses are still a fairly new phenomenon in Kenya, they are highly practical for school transportation “because the greatest challenge in transitioning to electric buses is often the distance a bus can cover per charge. We have those that can cover 600 kilometres per charge but we do not have them in the country yet. What we have are those that travel 100 to 200 kilometers per charge and that is highly suitable for school transportation as it fits their business model.”
Dr. Mwaniki says electrifying school transportation can also earn the sector carbon credits from carbon emission avoidance. The amount of carbon emission avoided by using electric buses can be put into the carbon trading scheme. But he says this has to be a very big project with many schools coming together and they can ultimately make enough money to run their electrified buses.
“Electric vehicles effectively reduce greenhouse emissions. These schools can therefore organize themselves, get clearance from the government, and start trading. Carbon trading from carbon emission avoidance within the school transport system is therefore viable and profitable towards the development of the school sector,” he advises.
Against this backdrop, Nthusi says, that all around the world, people are working to address air pollution and improve children’s health by reducing traffic-related pollution with restrictions on older and highly polluting vehicles and subsidies for new electric vehicles to ensure that children enjoy clean, safe and healthy school ride that they deserve.
This story is published with support from the Earth Journalism Network.
