Mars Dust Measured Down to 100 Nanometers Aboard Perseverance Rover

On Earth, airborne particulate matter below 2.5 micrometers is tied to a range of negative health effects because it can lodge deep in the lungs and pass into the bloodstream. Studies have shown that ultrafine particles, those no larger than 100 nanometers, can travel from the nasal cavity to the brain along the olfactory nerve.

Martian dust adds chemical hazards to the mechanical ones. It consists predominantly of silicate minerals and carries reactive compounds, including perchlorates (chemicals that can disrupt thyroid function) and reactive iron that induces cellular damage. The PIXL results confirmed the iron- and sulfur-rich composition earlier missions measured, and detected enrichment in phosphorus along with signs of calcium sulfate. Scientists believe the health risks depend on the quantity of dust and the length of exposure.

The study also showed that static electricity governs which particles stick to which surfaces. Dust grains become charged as they collide in the air, and different materials attract grains of different sizes. The finest particles stayed attached through years of driving and drilling.

"The existence of Mars dust at these ultrafine sizes has been predicted for a long time, and PIXL gave us the chance to measure it directly on Mars," said Scott VanBommel, a Perseverance scientist at Washington University in St. Louis and the paper's lead author. "The larger clumps, the Martian dust bunnies, get shaken off over time. But the smallest particles stay behind, and those are the ones that pose the greatest challenge for human support systems."

How does Mars dust differ from lunar dust?

The Apollo missions offer a cautionary record. Lunar dust scratched visors, degraded outer spacesuit layers, damaged seals, and left some crew members with symptoms resembling hay fever. Martian grains, rounded by wind-driven collisions, are less abrasive than their lunar counterparts. But they are enriched in sulfur, chlorine, and iron, contain more silica than lunar dust, and regional and global storms keep them recirculating through the atmosphere.

What is NASA already doing about it?

Several mitigation efforts are underway:

• The study found that some materials hold less dust than others, guiding future material and protective-coating choices.
• Designs such as suitports (which let astronauts climb into a suit attached to the outside of a habitat) and dual-chamber airlocks could keep dust out of living quarters.
• In March 2025, NASA tested an Electrodynamic Dust Shield, using electric fields to clear lunar regolith from glass and radiator surfaces on the Moon. Developed at Kennedy Space Center, it flew aboard Firefly Aerospace's Blue Ghost Mission 1.
• At Johnson Space Center's Lunar Development and Test Facility in Houston, engineers use vacuum chambers and lunar regolith simulant to test suit components and a handheld electrostatic dust mitigation tool ahead of Artemis missions.

"Perseverance's main job is to search for signs of ancient microbial life, but the mission was also designed to help prepare for human explorers," said Katie Stack Morgan, Perseverance's project scientist at NASA's Jet Propulsion Laboratory in Southern California, citing technology demonstrations such as MOXIE (Mars Oxygen In-Situ Resource Utilization Experiment) and the Ingenuity helicopter.

The results remain measurements from a single location and a small set of materials, and the health thresholds they imply will require further work. Still, they give engineers and flight surgeons something they have never had: direct, quantitative evidence of the smallest dust Mars will bring indoors.

The smallest grains, it turns out, are the ones that refuse to leave.