The crackdown on mechanically defective vehicles saves lives in more ways than one: beyond preventing accidents, it also clears the air of toxic fumes that quietly wreck our health, experts have warned.
This publication’s analysis of data from AirQo, Africa’s air quality monitoring network founded at Makerere University, shows that air quality in the Kampala Metropolitan Area improved by around 12 percentage points amid the crackdown on the defective vehicles.
The monitors installed by AirQo in different parts of the city determine air pollution by measuring tiny pollutants called Particulate Matter (PM).
The sizes of the pollutants, which have severe health effects, are 2.5 and 10, referred to as PM2.5 and PM10.
According to AirQo, the PM2.5 level was 36.8 µg/m³ between August 17 and August 23 before the crackdown.
But this declined to an average PM2.5 level of 32.4 µg/m³ between August 24 and August 30 when the crackdown on taxis in dangerous mechanical condition (DMC) started in Kampala. The World Health Organisation (WHO) tolerable 24-hour PM level is 15µg/m³.
‘Poorly maintained vehicles release pollutants such as particulate matter, carbon monoxide and nitrogen oxides,’ observes Dr Ivan Kimuli, a physician at Makerere University Lung Institute.
‘These pollutants irritate the airways, aggravate asthma and, with prolonged exposure, contribute to respiratory and cardiovascular diseases,’ Dr
Kimuli adds.
Particulate Matter (PM) is a tiny or microscopic particle in the pollutant capable of penetrating deep into the lungs and altering one’s health depending on the length of exposure. They are categorised based on size, which is PM10 and PM2.5.
Dr Kimuli explains that repeated exposure can cause continued irritation and inflammation of the airways, resulting in chronic coughing, mucus production and worsening breathing difficulties.
‘For people who are asthma-prone, the repeated exposure is going to aggravate that airway of yours; and then you get symptoms of bad breathing more often and getting worse and worse over time,’ he adds.
The expert further explains that particulate matter measuring 2.5 micrometres or less in diameter, commonly known as PM2.5, is particularly concerning because the particles can penetrate deep into the lungs and enter the bloodstream.
He says prolonged exposure to such pollution can increase the risk of chronic respiratory and cardiovascular diseases, while diesel exhaust contains components associated with cancer risk.
Dr Joel Mirembe Nsubuga, a physician, says people at more risk include those who spend long periods in traffic or near busy roads. This includes taxi operators, boda boda riders, traffic officers and roadside vendors who may face repeated exposure to car pollutants.
Dr Mirembe says people with asthma, chronic obstructive pulmonary disease (COPD), heart disease and high blood pressure face greater risks from prolonged exposure.
‘Diseases, especially the lung diseases such as chronic obstructive pulmonary disease, like asthma, increased risk of getting cancer, increased risk of getting strokes, blood pressure rise, among other things,’ he reveals.
Insufficient decline
According to AirQo, the data reported above is from 74 monitoring sites. The readings for both weeks, which are upwards of 32µg/m³, fall under a ‘Moderate’ Air Quality Index (AQI), which means air in Kampala did not become clean enough even after the crackdown on DMC taxis.
The WHO 24-hour tolerable PM2.5 level is 15µg/m³. According to AirQo, Monday, August 24, and Tuesday, August 25, had the highest PM2.5 levels of 35.2µg/m³ and 37.1µg/m³, respectively.
‘Sensitive groups should reduce prolonged or heavy outdoor exertion,’ AirQo states, in line with the WHO standards after recording the reading for the week ending August 30.
‘The air quality in the selected region requires attention. Further investigation and mitigation strategies are recommended,’ AirQo adds.
According to AirQo, the air quality in Kampala is a concern, with PM2.5 levels frequently exceeding WHO guidelines. ‘Local authorities should implement measures to reduce emissions from traffic and industry,’ AirQo advises.
Dr Steven Reynolds, a Kampala-based American scientist with an interest in environmental health factors , says bringing down air pollution levels to tolerable levels requires a dynamic shift.
‘Air pollution problem in Kampala is multifactorial,’ he observes. There are so many things contributing to it. Vehicles are definitely a major one.’
Dr Reynolds, who lives in Makindye, Kampala, says it is not only driven by the old taxis. ‘My voice is raspy because my neighbours are constantly burning garbage all around,’ he adds.
The government in July commenced the national cleaning days, and this is observed every last Saturday of the month. However, there are still reported gaps in garbage collection by the authorities.
Dr Reynolds also says the declining green spaces in the city deserves urgent attention. ‘We’re losing our green spaces; I feel like in Kampala, we’re so busy with these urban developments and high-rise condos,’ he explains
‘But we have lost the focus that we need to keep green spaces. And I’m concerned that the direction we’re going, we need to change many things,’ he adds.
According to scientists, seasonal changes also affect the concentration of pollutants such as PM2.5. Prolonged rain or downpours are more effective at washing suspended smoke and fine pollutants out of the atmosphere, according to researchers.
Mr Deo Okure, the air quality scientist at AirQo, explains the link. ‘When it is dry and windy, it tends to favour dilution of the pollution because transportation of the particles becomes higher,’ he explains.
‘Calm weather situations such as less wind tend to trap pollution closer to the ground because it cannot be dispersed. It is such pollution closer to the ground that affects people,’ he adds.
Emissions testing on vehicles
Dr Mirembe says vehicle emissions are an important contributor to urban air pollution, but cautioned against equating pollution only with visibly old or mechanically defective vehicles.
‘Most of the pollution comes from incomplete combustion of the fuel. Even a relatively new-looking vehicle can produce excessive emissions if its engine or emission system is poorly maintained,’ Dr Mirembe says.
He says this makes technical emissions testing essential if the crackdown is to deliver health benefits. He argues that the condition of a vehicle’s engine and emission system should be assessed alongside its physical appearance.
Dr Reynolds says the pollution can be reversed. ‘We need to have cleaner vehicles. I’m very happy to see the Spiro boda bodas on the road. I mean, those electric motorcycles,’ he says.
‘We need to really think about how we manage our traffic patterns and our vehicles as well as enforcing no garbage burning rules,’ he adds.
Dr Mirembe calls for mandatory periodic emissions testing of vehicles, stronger air-quality monitoring and measures to promote cleaner public transport as part of efforts to reduce exposure to harmful emissions.
‘The government should subsidise electric cars to get cheaper through lowering taxes with a lower production cost. Factories should also be regulated such that they purify the gases before they are released,’ he adds.
Data influencing policy
Mr Waiswa Ayazika, the former head of environment monitoring at the National Environment Management Authority (Nema), says with air quality data from monitors installed in the city and other parts of the country, ‘we have been able to make some important policy decisions’.
He says the actions include working with urban authorities such as KCCA to ensure roads are tarmacked, reducing traffic jam, promoting mass transport, non-motorised transport and use of electric vehicles or motorcycles.
Ms Sharifah Buzeki, the KCCA Executive Director, notes that there is a need for urgent, collective action to tackle worrying air pollution in Kampala.
She warned that deteriorating air quality poses a growing threat to public health and the city’s sustainability.
‘With the growing population, the air quality challenge is becoming more serious, but we are taking deliberate steps to address it,’ she says.
She linked the pollution to open burning of waste, traffic emissions and use of biomass fuels as major drivers of pollution.
Electric vehicles
Last week, the government, in a bid to reduce traffic emissions and improve mass transportation, deployed 21 electric buses in Kira Municipality, Wakiso District.
Ms Minsa Kabanda, the minister of Kampala and Metropolitan Affairs, says the introduction of the locally manufactured Kayoola electric buses is in line with government’s plan to establish a modern and efficient transport system in the Greater Kampala Metropolitan Area (GKMA).
‘It is aligned with the vision of a modern, integrated and efficient transport system for the Greater Kampala Metropolitan Area as envisaged under the GKMA Multi-Modal Urban Transport Master Plan,’ she says.
‘The government is planning to end traffic congestion and phase out old, polluting vehicles from the roads,’ she adds.
Most affected areas
Pollution Hotspots for August 24-30: Nansana east ward, Wakiso (91.7g/m³), Kireka, Kira Municipality (88.1 g/m³), Sir Apollo Kagwa Road (81.7g/m³) are the areas with the highest pollution levels.
Lower-Pollution sites: Water and Environment House, Luzira (14.2g/m³), Mpererwe, Kawempe (16.5g/m³), Kawempe Division (18.4g/m³) are the areas with lower pollution levels.
Key change: August 24-30; 32.4ug/m3. Moderate. (Sensitive groups should reduce prolonged or heavy outdoor exertion.)