Aerosol Climatology

1. Formation of ammonium nitrate aerosol is strongly temperature-dependent. Assume that:

• the sulfate aerosol concentration ($SO_4^{2-}$) is 1 ppb

• the total nitrate (gas-phase $HNO_3$ plus aerosol $NO_3^-$) is 4 ppb

• total ammonia (gas-phase $NH_3$ plus aerosol $NH_4^+$) is 7 ppb

• the temperature is $T = 10^\circ C$.

Estimate the total concentration of inorganic aerosol using the approximations derived in class.

2. Use thethermodynamic model AIM to verify your result. Assume $RH = 10\%$ ("Fixed relative humidity" = 0.1). The model assumed a volume of $1\; m^3$, so you need to convert the ppb values to $mol/m^3$ and convert the output back to ppb.

• Upload a screenshot of your model inputs and model outputs

• On paper show the appropriate unit conversions.

• Compare the model output to your result from 1.