Getting to the Heart of the (Particulate) Matter

The World Health Organization estimates that more than 99% of the world’s population breathes air that exceeds its health-based air quality guideline limits, and that millions of premature deaths can be attributed annually to breathing in air pollution. This explainer from NASA can help you to understand the scale and scope of the air pollution crisis, and especially of the dangers of particulate matter. It explains the nature and sources of particulate matter pollution; outlines the implications for human health; and highlights the efforts that are underway to determine the types and sources of particulate matter most harmful to humans.