Black plumes of smoke are often seen rising from the Agbogbloshie electronic waste (e-waste) site in Accra, Ghana. The acrid clouds contain particulate matter and other pollutants that pour into the air above the capital city from two waste-burning areas at the site. But air pollution data to track these plumes and their effects are limited in Ghana and throughout Africa; only 6 of the continent’s 47 sub-Saharan countries report levels of airborne particulate matter—the inhalable pieces of pollution that can wreak havoc on the human body.
Kwarteng et al. look to augment Ghana’s limited air pollution data by using moderate-cost sampling methods to quantify exposure to particulate matter less than 2.5 micrometers (PM2.5 ) and less than 10 micrometers (PM10) in diameter for the waste site’s thousands of employees and the densely populated communities nearby. The team measured upwind, on-site, and downwind PM concentrations using gravimetric and optical instrumentation to sample both upwind background levels of air pollution and contributions of the waste site while also accounting for local meteorological conditions.
Both PM2.5 and PM10 levels were significantly higher at the waste site than background levels, and 24-hour PM2.5 levels considerably exceeded both World Health Organization and Ghanaian EPA exposure guidelines. The team found that 24-hour PM2.5 levels at the e-waste site averaged 88 micrograms per cubic meter (µg/m3), or 57 µg/m3 higher than the average background level of 31 µg/m3; the authors note that background levels were largely attributable to biomass burning and traffic emissions. Downwind of the e-waste site, PM2.5 levels were 57 µg/m3 (or 26 µg/m3 higher than background). World Health Organization and Ghanaian EPA exposure guidelines for 24-hour PM2.5 are 25 and 30 µg/m3, respectively.
According to the authors, the study demonstrates that an approach combining gravimetric and optical measurements can provide a relatively low cost way for countries to monitor pollution levels in complex, urban environments. (GeoHealth, https://doi.org/10.1029/2020GH000247, 2020)
—Kate Wheeling, Science Writer