The NASA team’s conclusion: exposure to PM2.5 likely contributed to 2.89 million premature deaths in 2019—1.19 million from heart disease, 1.01 million from stroke, 287,000 from COPD, 230,000 from lower respiratory infection, and 166,000 from lung cancer. According to their estimates, roughly 43 percent of those deaths occurred in China and 23 percent in India—two of the most populous and polluted countries in the world. Other countries with significant exposure to PM2.5 and large numbers of premature deaths included Pakistan, Bangladesh, and Nigeria—though none of these countries accounted for more than three percent of the total deaths linked to PM2.5.

The analysis linked 22 percent of the premature deaths associated with PM2.5 to dust—much of this in a “dust belt” that spans from West Africa to East Asia.