Study Reveals Lunar Dust Is Less Harmful to Human Lungs Than Polluted Urban Air

Inhaling polluted air on a busy city street is more harmful to human lungs than breathing in lunar dust, Australian researchers have discovered.

Concerns regarding the toxicity of lunar dust arose during the Apollo missions. This dust is statically charged, allowing it to cling to astronauts’ suits. When crews returned to the lunar module, they inhaled dust that had accumulated in the air, leading to respiratory issues that typically resolved within 24 hours.

Harrison Schmitt, an astronaut from the Apollo 17 mission, described the experience as «lunar flu,» characterized by eye irritation, sneezing, and a sore throat. Upon their return to Earth, a physician associated with the lunar program noted similar symptoms after unpacking the used spacesuits. Researchers at the time suggested that repeated exposure to lunar dust might intensify its toxicity.

In a recent scientific study, the researchers conducted experiments using two types of lunar simulants—replicas of genuine lunar dust, employed due to the limited availability of original samples. These simulants closely resemble the lunar material found on the Moon’s dark volcanic plains and its older highlands. The particle sizes of the simulants were under 2.5 microns, which is small enough to be inhaled and retained in the lower respiratory tract.

The scientists introduced the simulant to two different types of lung cells: bronchial and alveolar, representing the upper and lower sections of the lungs, respectively. They then carried out a similar experiment with samples of particulate matter collected from a busy street in Sydney. Upon comparing the effects, the research team found that lunar dust impacts the lungs considerably less, though it still causes irritation.

The researchers noted that lunar dust does not appear to pose a risk for chronic diseases like silicosis, which is caused by inhaling silica dust, typically affecting construction workers.

This discovery by Australian scientists is particularly relevant in light of preparations for the Artemis 3 mission, during which humans will return to the Moon for the first time since 1972. NASA has scheduled the launch of this mission for mid-2027.