A new study, led by, has yielded the first-ever multi-year ambient PM2.5 dataset in Kinshasa and Brazzaville. The team deployed a cadre of low-cost sensors and interpreted data in the context of changing weather and changing human activity related to COVID-19 stay-at-home orders. The study was supported by two local universities and their scientists in both cities, and is
New research published online in Aerosol and Air Quality Research reports on findings from a multi-year monitoring program on air quality in African megacities Kinshasa and Brazzaville. The cities, capitals of the Democratic Republic of the Congo and the Republic of Congo, respectively, currently do not have national ambient air quality standards.
"Average PM2.5 concentrations suggest unhealthy levels of human exposure, which, over time, can lead to cardiopulmonary problems and premature death," said Lamont-Doherty Earth Observatory atmospheric scientist Daniel Westervelt, who led the investigation with Columbia University’s Celeste McFarlane. Fine particulate matter (PM2.5) is estimated to cause approximately 780,000 premature deaths every year in Africa and worsen diseases such as asthma, lung cancer, and chronic obstructive pulmonary disease.
The study was conducted using low-cost sensors over several years. "We were able to demonstrate that it is possible to robustly characterize air quality in African megacities using well-calibrated, relatively simple, cheap devices," Westervelt said.
The team found that PM2.5 is highest during the months of June, July, and August (which comprise the dry season). This period showed PM2.5 levels five times higher than World Health Organization guidelines recommend. Nevertheless, even in the rainy season, PM2.5 levels remained over four times higher than WHO guidelines.
Interestingly, the data collected also overlapped with pandemic-related stay-at-home orders, and the team’s analysis showed that these orders were associated with reductions in PM2.5 levels (up to a 40% decrease) similar to those seen in other parts of the world at the same time.
The researchers hope that their work will call on the governments of African megacities to invest in air quality monitoring programs in an effort to reduce adverse public health impacts.