// multi-utility computation suite · offline · instant · precise
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eng.air-pollutant-dispersion Calculator
Calculates downwind air pollutant concentration using the Gaussian plume model from emission rate, stack height, and atmospheric stability class. The Gaussian model is the regulatory default for air quality impact assessment — complex terrain and building wake effects require numerical modelling.
Inputs
Q G S
Amount per unit of time or per unit quantity. Check the denominator before interpreting.
U M S
Rate of movement. 1 m/s = 3.6 km/h = 2.237 mph.
Sigma Y M
Reference formula or conversion factor shown for context.
Sigma Z M
Reference formula or conversion factor shown for context.
H M
Vertical measurement. For health calculators, typically standing height without shoes.
X M
Separation between two points or total path length. Check that units are consistent throughout the calculation.
Results
centerline ground concentration (μg/m³)
The proportional relationship between two quantities.
max ground-level concentration (μg/m³)
The proportional relationship between two quantities.
C = Q/(π·σy·σz·u)·exp(-H²/2σz²)
Reference formula or conversion factor shown for context.
EU PM2.5 limit
Reference formula or conversion factor shown for context.
stability class matters
Measure of how robust the system, structure, or process is to perturbations. Low stability means small changes can cause large deviations.