Air quality monitoring stations could help track and preserve threatened species

Earth is facing a biodiversity crisis, with species extinction accelerating at a startling pace. Policy action is finally catching up with the dilemma, as the United Nations reached a historic deal to protect 30 percent of the Earth’s wilderness by 2030 in December 2022. Addressing this crisis will face an uphill battle– including the infrastructure needed to quantify these losses.

[Related: Why you can’t put a price on biodiversity.]

This crucial data may now come from a surprising source: air quality monitoring stations. In a study published June 5 in the journal Current Biology finds that for decades, thousands of these ambient air quality monitoring stations all over the world have inadvertently been collecting environmental DNA (eDNA) in their filters.

“One of the biggest challenges in biodiversity is monitoring at landscape scales—and our data suggest this could be addressed using the already existing networks of air quality monitoring stations, which are regulated by many public and private operators,” study co-author and York University ecologist Elizabeth Clare said in a statement. “These networks have existed for decades, but we have not really considered the ecological value of the samples they collect.”

Air quality monitoring stations have been around for decades, but methods of capturing and analyzing eDNA are relatively new. Data from previous studies offered proof-of-concept evidence that it was possible to identify the species in a zoo by sampling the air.

In this new study, a team of researchers tested whether airborne eDNA that holds information on local plant, insect, and other animal life is captured on these filters as a by-product of the normal operations of air quality monitoring networks. These networks  typically monitor for heavy metals and other pollutants. 

They extracted and amplified DNA from the filters at two locations in the United Kingdom and recovered eDNA from over 180 different fungi, plants, insects, mammals, birds, amphibians, and other animal groups. The species list included many charismatic species, including badgers, dormice, little owls, and smooth newts. Additionally, they were able to pick up DNA from species of special conservation interest such as hedgehogs and songbirds. Trees and plants included ash, linden, pine, willow, oak, yarrows, mallows, daisy, nettles, and grasses. DNA from arable crops such as wheat, soybean, and cabbage was also identified, according to the study.

Additionally, the filters contained DNA from 34 species of birds. Data showed that longer sampling times captured a larger number of vertebrate species, possibly as more birds and mammals visited the area over time. 

[Related: We don’t have a full picture of the planet’s shrinking biodiversity. Here’s why.]

According to the team, air quality monitoring networks have been gathering local biodiversity data in a very standardized way, but the ecological significance has long gone unnoticed. Samples are kept for decades in some places, which suggests that existing samples that capture ecological data over time may already exist. With only some minor changes, these samples could be used for detailed monitoring of land-based biodiversity using a network already in full operation.

“The most important finding, to my mind, is the demonstration that aerosol samplers typically used in national networks for ambient air quality monitoring can also collect eDNA,” James Allerton, a co-author and an air quality specialist from the UK’s National Physical Laboratory. said in a statement. “One can infer that such networks—for all their years of operation and in other countries around the world—must have been inadvertently picking up eDNA from the very air we breathe.”

The team is currently working to preserve as many of these samples as they can with eDNA in mind. The team says it will take a global effort to reach all of their trove of biodiversity data. 

“The potential of this cannot be overstated,” study co-author and Queen Mary University of London biologist Joanne Littlefair said in a statement. “It could be an absolute game changer for tracking and monitoring biodiversity. Almost every country has some kind of air pollution monitoring system or network, either government owned or private, and in many cases both. This could solve a global problem of how to measure biodiversity at a massive scale.”