ADMS NOx Chemistry Scheme Implemented in AERMOD
A journal article by CERC authors describes the implementation of a NOx chemistry scheme in AERMOD which uses similar reactions and an analogous calculation method to the ADMS GRS chemistry. The new chemistry scheme, ADMSM, shows good performance when compared to measurements from five validation studies. The NO2 predicted by ADMSM has increased consistency with modelled NOx compared to the OLM or PVMRM approaches in AERMOD. The figure shows a comparison of predicted average hourly NO2 to NOx ratios against the observed value for cases where observed NOx ≥ 20 µg/m3; studies presented according to source-receptor distance (closest on left). The code development work carried out by CERC was funded by the American Petroleum Institute.
This work is cited in the recent US EPA “White Paper on Planned Updates to AERMOD Modeling System”, and will be further evaluated as an alternative model for Tier 3 NO2 modelling in AERMOD.