Calculates ground-level concentration from a continuous stack emission using the Gaussian plume model: C = Q/(2πσyσzu) × exp(−y²/2σy²) × [exp(−(z−H)²/2σz²) + exp(−(z+H)²/2σz²)]. Dispersion coefficients σy and σz depend on Pasquill-Gifford stability class A–F and downwind distance.
Inputs
Q Gs
Amount per unit of time or per unit quantity. Check the denominator before interpreting.
U Ms
Rate of movement. 1 m/s = 3.6 km/h = 2.237 mph.
X M
Separation between two points or total path length. Check that units are consistent throughout the calculation.
Stability Class
Reference formula or conversion factor shown for context.
H M
Vertical measurement. For health calculators, typically standing height without shoes.
Results
ground-level concentration C (μg/m³)
The proportional relationship between two quantities.
σy (m)
Reference formula or conversion factor shown for context.
σz (m)
Reference formula or conversion factor shown for context.
C = Q/(π·σy·σz·u)·exp(−H²/2σz²)
Reference formula or conversion factor shown for context.
stability class context
Measure of how robust the system, structure, or process is to perturbations. Low stability means small changes can cause large deviations.