Chapter 04 · By the numbers
The scale of the problem.
Air pollution isn't an abstract issue. It has a death toll, a hospital bill, and a footprint on every continent. Here's what the numbers actually look like.
7M
premature deaths per year (WHO, 2024)
$8.1T
estimated global cost of air pollution / year (World Bank)
2.1yr
average life expectancy lost worldwide (AQLI, U. of Chicago)
70K
excess deaths in Europe's 2003 heat wave, tied to pollution & heat
Annual average AQI, selected cities (2023)
The U.S. EPA's Air Quality Index runs from 0 to 500. Anything above 100 starts to get uncomfortable for sensitive groups; above 150 is bad for everyone.
Delhi, India
168
Beijing, China
121
Mexico City
92
Los Angeles
71
London
42
Reykjavik
15
0–50 Good
51–100 Moderate
101–150 Unhealthy for sensitive
151+ Unhealthy
Source: IQAir World Air Quality Report, 2023.
Environmental justice
"Black Americans are exposed to 21% more PM2.5 than the U.S. average."
— PNAS, 2019. In the U.S., low-income and minority neighborhoods are far more likely to sit next to highways, ports, and industrial plants. The result is measurable: more asthma, more heart disease, and shorter lives.