How can fog droplets remove pollutants?

Fog is more than weather: microbes may do cleanup

Researchers have discovered that fog droplets can act as tiny living habitats. In work focused on atmospheric fog, scientists found that fog droplets host living bacteria that can grow within the droplets. This turns fog from a passive meteorological phenomenon into an active microbial system.

The most consequential implication is the potential role fog could play in air chemistry. Because the bacteria remain viable inside the droplets, they may help remove harmful pollutants from the atmosphere—suggesting a previously underappreciated pathway for cleansing air under certain weather conditions.

This matters for both environmental science and climate-related atmospheric modeling. Atmospheric models typically treat fog in terms of how it scatters light, affects visibility, and alters the transport and residence time of gases and aerosols. If biological activity inside fog droplets contributes to pollutant removal, then models may need to account for microbe-driven processes in addition to purely chemical and physical mechanisms.

Key points highlighted by the story include:

• Fog droplets can contain living bacteria.
• The bacteria can grow while suspended in the droplets.
• The microbial activity may help remove harmful pollutants.

The finding also points to broader questions researchers will likely pursue next: which pollutants are affected, under what atmospheric conditions fog biology is most active, and how widespread the phenomenon is across different regions and seasons.

As a result, this work reframes fog as part of the planet’s biogeochemical system. Even though fog is often considered temporary and local, it could have a meaningful influence on the air we breathe by enabling microbial “work” at the scale of droplets.