Air pollution is still a big health problem, especially in places where people burn fuel to light their homes and to cook. What if the tiny particles in the air don’t just hurt our lungs, but also change the mix of bacteria and viruses in our bodies, especially in our gut? Our team worked on a study led by Dr. Peggy Lai, published in May 2025, that looked at what happened when people in rural Uganda using kerosene lighting were given solar lights. The study found that using solar lighting helped adults—especially women—breathe better and also changed the types of bacteria and viruses living in their gut.
Key Takeaways from the Study
- Air pollution affects more than the lungs: Even though the female participants still cooked with stoves that burn wood or charcoal, switching from traditional lighting to solar lights lowered their exposure to indoor air pollution. This didn’t just help the air—they also saw changes in both the bacteria and viruses in their gut.
- Cleaner air, fewer symptoms: Women who got solar lighting had fewer breathing problems. Before the study, more than half (57.1%) had breathing symptoms, but that dropped to just over a third (36.1%) after switching to solar lighting.
- The gut and lungs are connected: Changes in the gut’s microbes that showed up after air got cleaner were linked to better breathing health. People with those changes in their gut had a 32% lower chance of having breathing symptoms. This means that helping our gut microbes might be a good new way to improve our lung health after breathing polluted air.
Recent studies have shown a connection between air pollution and the microbiome, but it’s been hard to fully understand because other things, like what people eat and how much money they have, can also affect those results. In our study, we used a special way of testing called a randomized controlled trial, which helped us see more clearly what was really happening. We found that cutting down indoor air pollution with solar lighting didn’t just help people breathe better—it also changed the microbes in the body. In particular, we saw clear changes in both the bacteria and viruses in the gut after the solar lighting was used. Even more interesting, these gut changes happened along with fewer breathing problems, which shows that the gut and lungs may be connected (“gut-lung axis) in ways that can affect our health.
After using the clean solar lighting, we saw changes in all types of microbes in the gut —Eukaryota, Archaea, Bacteria, and Viruses (Figure A). People’s breathing symptoms also got better after using the clean lighting (Figure B).
These results show there are new, exciting ways to help protect people’s health when it comes to air pollution. Cleaner energy at home could not only lower breathing problems, but also support a healthier microbiome—the helpful microbes in our bodies that we don’t always think about, but that play a big role in keeping us healthy. Our findings suggest that, in the future, when we try to reduce the health problems caused by air pollution, we should pay attention to the gut microbiome, using it as a sign of health and as something we can also work to improve.
Read the full study: https://ehp.niehs.nih.gov/doi/10.1289/EHP16002