A clip-on optical particle spectrometer combined with minute ventilation. Ambient weather stations measure the air; AeroDose measures the dose, and signs the record.
A weather station reports how dirty the air is. It cannot tell you what a person inhaled, because the same air can deliver three to three to four times the particulate to someone clearing fireline as to someone standing nearby — the difference is how hard they are breathing. A wildland firefighter under load moves 40–60 L/min through their lungs; an observer at rest moves 12–16.
So AeroDose integrates both: the measured concentration, the worker's modelled ventilation, and the fraction of each particle size that actually deposits in alveolar tissue.
The dashed line in the chart above is what the same air would have delivered to a resting observer. The gap between the two lines is the part of the hazard that concentration monitoring misses entirely.
| Component | Choice and why |
|---|---|
| Sensing | Sensirion SPS30 laser scattering with auto-cleaning fan cycles, so soot and dust do not foul the optical path. |
| Compute and radio | Nordic nRF52840, sub-milliwatt Bluetooth LE 5.2 logging, sized for a shift on one cell. |
| Evidence | SHA-256 log signed in a hardware TPM, so a recorded dose stands up as an occupational record rather than a memory. |
| Alerting | Tactile vibration before the cumulative figure approaches the permissible limit, while the worker can still act on it. |
git clone https://github.com/KELLERBABG/AeroDose.git cd AeroDose && cargo test # dosimetry verification suite
Scope. A measurement and record-keeping instrument. It reports exposure against a limit; it is not a respirator and does not protect anyone.