University of Gothenburg researchers have found genes that can make bacteria resistant to antibiotics in samples of polluted air from Beijing, China, meaning that such air could potentially spread that DNA between bacteria, according to a study in Microbiome. The resistance genes were particularly prevalent in areas where air and water pollution stemmed from antiobiotic manufacturing.

Time explains that the findings don’t necessarily mean that people can get drug-resistant infections from the air, so rather than being a cause for alarm, the research should spur scientists to investigate polluted air as a means for the resistance genes themselves to be transmitted. The resistance genes have “potential to be transferred to pathogens in the future,” the study says — the live pathogens are the point where the genes become more dangerous to human health.

Read: Air Pollution Kills Kids

Resistance to antibiotics is a growing threat to health and medicine. According to the study, it causes more than 700,000 deaths every year. Many of the genes that make organisms resistant to antibiotics may have “an environmental origin” going back many years, but modern production of antibiotics has only made the problem worse: “The use and abuse of antibiotics have increased the prevalence of resistance genes in the human and animal microbiome over the last 75 years,” the study says. “Understanding of the environment as a source and dissemination route for [antibiotic resistant genes] is fundamental in order to identify risk scenarios for human health.”

Time cites estimates of the annual death toll by drug-resistant infections to hit 10 million by 2050. Study author Joakim Larsson, director of the Centre for Antibiotic Resistance Research at the University of Gothenburg, told that publication, “We think this is really under-investigated and not taken seriously.” He also called for more regulation for industrial waste disposal, in light of the suggested link between pharmaceutical manufacturing waste and higher numbers of drug resistance genes in the air.

Source: Larsson DGJ, Pal C, Bengtsson-Palme J and Kristiansson E. The structure and diversity of human, animal and environmental resistomes. Microbiome. 2016.

See also:

Will a Genetically Engineered Virus Kill Us All?

Deadly Drug-Resistant Fungus Hits Hospitals

City Air and Noise Raises Blood Pressure