The use of integrated assessment models, which combine models from different fields, raises the need for developing specific modelling concepts in order to provide results to support policy decisions within a practical time frame. Integrated assessment models for air policy relate technologies, the emitting sources, with air quality levels. Existing photochemical air quality models are not directly suitable for integrated approaches as they are time intensive in terms of input preparation and simulation speed.

This work presents the methodology and the development of a dedicated air quality model for an integrated assessment model. This approach has been designed for the Luxembourg Energy and Air Quality, LEAQ, integrated assessment model. It combines an air quality model, AUSTAL2000-AYLTP, with a techno-economic model, ETEM, which computes ozone precursors emissions related to energy consumption. The models are coupled via an optimization engine, which minimizes the total energy cost for a given ozone level.

AUSTAL2000, a Lagrangian transport model, has been adapted to receive a photochemical module, the AsYmptotic Level Transport Pollution, AYLTP. This module consists of a Look-Up Table of quasi-linear reaction rates. A balance has been found that gives an acceptable level of accuracy, given the reduction of computational time. The development of such methodologies is important when considering integrated assessment models.

Furthermore, the results of the air quality model have been compared with measurements, and with the regional model LOTOS-EUROS. Additionally, the air quality model has been used within the in LEAQ model. Two study cases have been simulated, one including only the national emissions from Luxembourg country, and a second one for the Luxembourg region, including the neighbouring countries emissions.

The use of quasi-linear reaction rates obtained with the help of the lookup table represents an innovative step towards the use of simplified air quality models that involve complex chemistry.