The Health and Economic Impacts of Dirty Skies

In Morocco, studies reported stark decreases of air pollutants in several cities, including Marrakech, Casablanca, and Salè (Khomsi et al. 2020; Otmani et al. 2020)—a finding confirmed on a national level (Sekmoudi et al. 2020).

In Tunisian cities, the imposed measures, including a general lockdown, caused marked decreases, lowering NO2 and sulfur dioxide (SO2) levels by around 50 percent in Sfax, 40 percent in Tunis, and 20 percent in Sousse. Furthermore, PM2.5 concentrations dropped by around 20 percent, 7 percent, and 23 percent, respectively, in those cities while the concentrations of particles with a diameter of 10 microns or less (PM10) did not significantly change (Chekir and Salem 2020). As those authors put it, “In other words, one side effect of this horrific virus is cleaner Tunisian air” (Chekir and Salem 2020, 7).

In the Islamic Republic of Iran, Tehran exhibited significant decreases in SO2 (varying by a range of 5–28 percent in different parts of the city); NO2 (by 1–33 percent); PM10 (by 1.4–30 percent); and carbon monoxide (CO) (by 5–41 percent), while ozone and PM2.5 levels increased by a range of 0.5–103 percent and by 2–50 percent, respectively (Broomandi et al. 2020). Those authors attribute the latter two findings to unfavorable meteorological conditions and conclude that air quality improved overall, noting that these experiences “clearly showed that it is possible to have significant air pollution reduction in megacities by effective traffic control programs along with the promotions of green commuting and the technologies to expand remote working” (Broomandi et al. 2020, 1800).

As the measures to curtail COVID-19 are lifted, air pollution levels are expected to bounce back. The question is, to what extent? These significant reductions demonstrate that it is possible to rapidly reduce air pollution. Furthermore, the hope is that emissions will rebound to lower than prepandemic levels in the medium term as governments focus on greening their recoveries from COVID-19.

THE HEALTH AND ECONOMIC IMPACTS OF DIRTY SKIES

AAP has emerged as a major cause of illness and death globally (Boogard, Walker, and Cohen 2019) and in the Middle East and North Africa specifically. It has also been found to disproportionately affect lowerincome groups (Hajat, Hsia, and O’Neill 2015; Miranda et al. 2011). Various air pollutants affect human health, but PM—especially the very small PM2.5—has been found to be especially hazardous, having the largest health effects globally (GBD 2018). Box 3.1 compares PM2.5 with PM10.