High-resolution emission inventory of the Lombardy region: development and comparison with measurements

In the framework of the EUROTRAC-2 subproject limitation of oxidant production an emission inventory was developed for the Lombardy region in Italy with a 1 h temporal and 3 km spatial resolution. The emissions were processed in a bottom-up approach. We outline the emissions processing strategy used and summarize the inventory characteristics. Spatial maps and diurnal series charts of the total emissions of nitrogen oxides (NOx), carbon monoxide CO, volatile organic compounds (VOC) are provided. The emission inventory shows distinct patterns for the urban area and the non-metropolitan region. We compare ratios of CO to NOx and CO to different VOC-classes between the emission inventory and measurements performed at two sites representative for the urban and non-metropolitan areas. Ratios were determined from the slopes of correlations between CO and the respective species class. Observed CO/NOx ratios are higher in the urban and non-metropolitan area by factors of 2 and 3, respectively. CO/VOC ratios show different discrepancies depending on the VOC-class but are generally lower in the emission inventory. Observations at the two sites yielded similar concentration ratios opposite to the inventory.