The Math Behind the Breath
This calculator implements the Fick Principle adapted for terrestrial respiration during graded exercise. Baseline values derived from:
VO₂ max scaling
Resting O₂ consumption = 3.5 mL·kg⁻¹·min⁻¹ (standard MET definition)
Exercise multiplier follows exponential curve: VO₂ = 3.5 × (1 + 0.018 × intensity²)
Alveolar ventilation
Minute ventilation = Tidal Volume × Respiratory Frequency
TV scales from 0.5L (rest) to 2.5L (max effort)
RF scales from 12 bpm (rest) to 45 bpm (VO₂ max)
Surface absorption coefficients
Bare soil: 0.02 mg·cm⁻²·hr⁻¹
Leaf litter: 0.15 mg·cm⁻²·hr⁻¹
Moss carpet: 0.47 mg·cm⁻²·hr⁻¹ (Bryum argenteum field measurements)
Biocrust: 0.89 mg·cm⁻²·hr⁻¹ (cyanobacterial fixation peak)
Note: Net atmospheric shift represents the theoretical ppm change in a 1-hectare enclosed ecosystem over one hour of sustained activity. Real-world dispersion reduces this by ~94%.