NASA's MAIA Sensors Reveal Detailed Picture of Addis Ababa's Air Pollution

NASA's Multi-Angle Imager for Aerosols (MAIA) mission has been using a network of 10 rooftop air sensors in Addis Ababa, Ethiopia, to produce one of the most detailed looks yet at the city's air pollution. Over three years, the sensors measured particulate matter 2.5 micrometers or smaller in diameter, known as PM2.5, one of the world's deadliest forms of air pollution.

Black carbon, or soot, produced by diesel vehicles, fires and other combustion sources, is an important component of Addis Ababa's particulate pollution. The MAIA sensors revealed how the city's pollution changes by time of day and season, including spikes tied to rush-hour traffic and holiday celebrations, with air quality across monitoring stations varying between 20 and 40 micrograms per cubic meter. Black carbon has been linked to low birth weight, brain development effects, respiratory conditions and premature mortality; the 2025 State of Global Air Report, cited in the mission's paper, estimates that PM2.5 particles, some small enough to enter the bloodstream, are linked to around 4.9 million excess deaths per year globally.

MAIA's air pollution research covers about a dozen regions worldwide, including three in the United States centered on Los Angeles, Atlanta and Boston, and mission scientists say the Addis Ababa findings are relevant to cities elsewhere, including in the US.

The mission combines its ground-based sensor network, already in operation, with a space observatory carrying a camera built at NASA's Jet Propulsion Laboratory, which is designed to identify different types of PM2.5 aerosols by how they reflect light. The observatory is set to launch on an Italian Space Agency satellite no earlier than late 2027.