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Which tiny particles besides gases are found in Earth’s atmosphere?

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Wispy cirrus clouds stretch across a bright blue sky above trees and a river at Pinawa Dam Provincial Park in Manitoba, Canada, with sunlight illuminating the scene. — Atmosphere The atmospheres of planets in the solar system are composed of various gases, particulates, and liquids. They are also dynamic places that redistribute heat and other forms of energy. On Earth, the atmosphere provides critical ingredients for living things. Here, feathery cirrus clouds drift across the deep blue sky over Pinawa Dam Provincial Park, near Pinawa, Manitoba, Canada.

In addition to gases, Earth’s atmosphere contains a variety of tiny solid and liquid particles known as aerosols. These particles are suspended in the air and play a vital role in atmospheric processes, such as serving as nuclei for the formation of clouds, raindrops, and snowflakes.12

These atmospheric particulates include:

Dust: A broad category of microscopic particles derived from sand, soil, rock fragments, and manufactured materials.2
Biological Matter: This includes pollen, mold spores, mites, bacteria, viruses, and fragments of organic tissue like skin cells and hair.2
Pollutants: Various human-made and natural substances, such as soot, ash, smoke, and fumes from heavy metals like copper, iron, and mercury.32

These particles vary significantly in size, ranging from tiny Aitken nuclei (less than 0.1 micrometres) to larger dust particles that can exceed 100 micrometres. While they are essential for weather patterns, many of these particulates—particularly fine inhalable particles—can pose significant risks to human health when they enter the respiratory and circulatory systems.132