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Breathe easy this Christmas: Holiday season brings healthier air in Rwanda

By: Nehemie

Help Santa fly in clean air. 

-Egide Kalisa

All types of vehicles on the road release gaseous air pollutants that lead to drastic increase in air pollution concentrations. The vehicular emissions have negative impacts on human health and reduce road visibility. Yet all we want for Christmas is air we can breathe. But what is the status of air pollution during Christmas festivities in Rwanda?

Low-cost air quality sensors may help to provide the answer to this question. Using an ultra-portable handheld monitor Aeroqual Series 500 and air visual node AQ analyzer, particulate matters PM2.5 (particles less than 2.5 μm in diameter that can enter the lungs) and PM10 (particles less than 10 μm in diameter that are trapped in the nasopharyngeal tract) were collected from the 25th December 2017 to 1st January 2018.

The average levels of PM2.5 and PM10 measured around Kigali city  on Christmas was substantial low and even below the global median set by WHO ambient air quality guidelines. The days following Christmas, air pollution concentration continuously increased at all sampling sites and the highest concentrations were observed on the 30th and 31st December 2017.

The results implicated that vehicle emissions may be major contributor to the concentration of PM2.5 and PM10 in Kigali city.


Fig. 1 Sampling around Kigali city on Christmas (2017) using ultra-portable handheld monitor Aeroqual Series 500 and air visual node analyzer, inexpensive sensors that can be deployed in dense networks to monitor criteria pollutants.


Fig.2 Implication of vehicle emissions on average concentration of PM2.5 and PM10 recorded at Kigali main road (KN3 RD)

Many African cities have growing air quality problems and vehicle emissions are major contributors of ambient PM2.5 and PM10. Few countries have air quality monitoring systems in place. Low cost air quality sensors have the potential to bridge this data gap.

African countries should take necessary measures to improve the public transport (promote walking and cycling) in the city and strict regulations on the importation of used vehicles.

Author: Egide Kalisa


Egide Kalisa received a First-class honours B.S degree in Botany and Conservation from the National University of Rwanda, an M.S. in Air Pollution Management and Control from the University of Birmingham, UK. By age of 25, As a Ph.D. student, He was awarded the Scholarship, which allowed him to conduct research at the Auckland University of Technology in New Zealand. Today, He is conducting the research in Rwanda, New Zealand and Japan on ambient air pollution that will help country’s government combat air pollution. Around Kigali city and Musanze district, Kalisa has been measuring key air pollutants PM2.5 and PM10, and testing them for polycyclic aromatic hydrocarbons (PAHs) and their nitrated derivatives (NPAHs), which are one of the most studied families of organic compounds, given their proven carcinogenic effects on humans. His research interests include atmospheric pollution, aerobiology, climate change, biodiversity & conservation and Health effect of air pollution.