Air Quality

Air quality calculators and formulas for pollutant dispersion and mass balance. Includes emission rate, concentration gradient, and Gaussian plume dispersion calculations.

8Formulas

All levels Difficulty

Updated Jul 2026

← All Environmental Engineering (31) Air Quality (8)

Fundamental

Particulate Matter Mass Concentration

C = m / V

Fundamental

Combined Sound Level from Multiple Sources

L_total = 10*log10(Σ 10^(Li/10))

Fundamental

Noise Level Attenuation with Distance

L2 = L1 - 20*log10(d2/d1)

Fundamental

Air Changes per Hour (Ventilation Rate)

ACH = (Airflow Rate (m3/hr)) / Room Volume (m3)

Fundamental

Stack Emission Rate

E = C * Q

Fundamental

Air Quality Index (AQI) Linear Interpolation

AQI = ((AQI_hi - AQI_lo)/(C_hi - C_lo)) * (C - C_lo) + AQI_lo

Fundamental

Gaussian Plume Concentration

C(x,y,0) = Q/(πuσ_yσ_z) · exp(−y²/2σ_y²)

Fundamental

Mass Balance (General)

Accumulation = In − Out + Generation − Consumption