Fog’s bacteria actively consume pollutants, new study says

fog’s bacteria – A new study finds that millions of bacteria live inside tiny fog droplets, staying active as fog forms. Researchers say the microbes can consume pollutants and may play a role in air chemistry—while raising new questions about what happens if communities harve

On a still, foggy morning, it’s easy to think of the haze as nothing more than water hanging in the air. A new study challenges that view—describing fog instead as a living habitat where bacteria are not just present, but growing and breaking down pollutants.

“We found that millions of bacteria inhabit … fog droplets. ” Ferran Garcia-Pichel. a co-author from Arizona State University. said in an email. He and his team reported that bacteria floating in tiny fog droplets are alive, multiplying and consuming atmospheric pollutants. “Not only are they there, they are actively consuming atmospheric pollutants, and likely also growing in them. Fog is a habitat,” Garcia-Pichel said.

The finding matters because fog is common and close to people—showing up where air quality. transportation visibility. and even water access are all affected. Fog is widespread. it can reduce visibility for transportation and air traffic. and it can become a source of water that helps drive entire ecosystems. For some communities, it can also be a source of drinking water, and it can enable certain atmospheric chemical processes.

The study builds on what scientists already suspected. Researchers have known that bacteria drift around in the air and clouds. but what they do there—especially in fog—has been “somewhat of a mystery. ” particularly because “there’s very limited knowledge about what kinds of bacteria are present in fogs. which are like clouds at the ground level. ” paper lead researcher Thi Thuong Thuong Cao said in a statement.

Fog not alive, but full of activity

Garcia-Pichel described it in a way that lands closer to everyday reality. “Fog is not alive, in the same way that the ocean is not alive, but like it, it contains active forms of life,” he told the outlet.

He also pointed to why fog is such a compelling place for microbes to exist. Garcia-Pichel said he studies fog because “liquid water is a necessity for life.” In his view. of all sources of liquid water on Earth. “fogs and clouds represent the only form of stable liquid water in the atmosphere. ” and “fog is closer to us than clouds.”.

The researchers sampled real-world fog in Pennsylvania. They collected fog droplets associated with 32 weather events over two years. drawing from Susquehanna University in Pennsylvania and Arizona State University. Among the bacterial groups found in the samples, one group stood out: methylobacteria.

Methylobacteria are known to consume simple carbon compounds, including chemicals such as formaldehyde. Formaldehyde is described as a common pollutant that adds to ozone smog and harms human health.

How much fog’s microbes add up

The team found that fewer than 1% of fog droplets contain bacteria. But when the droplets are averaged together. the microbes add up to an “astounding amount of life.” Arizona State said the concentration matches levels found in the ocean. “When you take all of the droplets together. the concentration of bacteria is the same as in the ocean. ” Garcia-Pichel said. He added that “A thimble’s worth of fog water has some 10 million bacteria.”.

The study also makes clear that it doesn’t settle the most important question: whether fog’s microbial activity ends up being more beneficial to people than harmful—especially when fog is treated as a resource. Garcia-Pichel warned that capturing fog could change the ecosystem of microbes in the air.

“If we harvest fog, we are getting rid of our little friends in the air,” Garcia-Pichel said. “We don’t know if that’s going to make a big impact or not, but we should be considering that.”

Radiation fog, sampled before and after formation

What’s new in the research is how the team chose its fog. Garcia-Pichel said “the most important part is that we chose to study radiation fog.” In his explanation. radiation fog forms under stagnant air conditions. That matters for sampling because it allowed the researchers to collect and observe bacteria in radiation fog precisely before. during. and after formation.

The National Weather Service describes radiation fog as a very common type of fog throughout the United States. It is most prevalent during the fall and winter, and forms overnight as the air near the ground cools and stabilizes.

Garcia-Pichel said the choice helped solve a long-standing problem in fog and cloud research. “This was so far a big problem when studying other types of fogs or clouds,” he explained. Studying radiation fog gave the team an advantage “to detect local microbial processes. without having to worry about them being ‘gone with the wind.’”.

Where that leaves the question of “cleaning”

For now, the study provides a vivid new picture of what’s happening in the haze people walk through: millions of bacteria living in droplets, consuming pollutants, and carrying out active processes in the air. It also puts a spotlight on the tradeoffs that come with treating fog as water.

For communities that rely on fog harvesting. the findings add urgency to research on outcomes—what changes when the droplets are collected instead of drifting through the atmosphere. And for anyone tracking air quality in the places where radiation fog is common. the presence of methylobacteria and their ability to consume formaldehyde points to a new possibility: that fog isn’t just a visibility problem. It may also be part of the chemistry of the air itself.

fog bacteria study methylobacteria formaldehyde air pollutants ozone smog radiation fog Susquehanna University Arizona State University air chemistry fog harvesting