Impact of NOx and NH3 Emission Reduction on Particulate Matter across Po Valley: A LIFE-IP-PREPAIR Study

Abstract

Air quality in Europe continues to remain poor in many areas, with regulation limits often exceeded by many countries. The EU Life-IP PREPAIR Project, involving administrations and environmental protection agencies of eight regions and three municipalities in Northern Italy and Slovenia, was designed to support the implementation of the regional air quality plans in the Po Valley, one of the most critical areas in Europe in terms of pollution levels. In this study, four air quality modelling systems, based on three chemical transport models (CHIMERE, FARM and CAMx) were applied over the Po Valley to assess the sensitivity of PM2.5 concentrations to NOx and NH3 emission reductions. These two precursors were reduced (individually and simultaneously) from 25% up to 75% for a total of 10 scenarios, aimed at identifying the most efficient emission reduction strategies and to assess the non-linear response of PM2.5 concentrations to precursor changes. The multi-model analysis shows that reductions across multiple emission sectors are necessary to achieve optimal results. In addition, the analysis of non-linearities revealed that during the cold season, the efficiency of PM2.5 abatement tends to increase by increasing the emission reductions, while during summertime, the same efficiency remains almost constant, or slightly decreases towards higher reduction strengths. Since the concentrations of PM2.5 are greater in winter than in summer, it is reasonable to infer that significant emission reductions should be planned to maximise reduction effectiveness.

Application of Machine Learning to Estimate Ammonia Atmospheric Emissions and Concentrations

“…The applied temporal patterns play an important role, affecting the simulation results both in diagnostic and scenario elaborations. Veratti et al [17] report an overview of the temporal distribution in northern Italy of NH 3 emissions, applying four different air quality modelling systems based on three chemical transport models (CHIMERE, FARM, and CAMx) [52][53][54][55][56][57][58]. The minimum and maximum monthly NH 3 emissions are reported in Figure 8 and compared to the calculations obtained by this study for the site 3_RB, considering the whole time series.…”

“…The comparison demonstrates how the profiles derived in this study using in situ measurements have greater variability for each month and can exhibit multiple relative peaks throughout the year. The temporal profiles reported by Veratti et al [17] were obtained from four different air quality modelling systems applied to the Po Basin. They are fixed temporal profiles derived from an estimation of the potential activities associated with livestock and manure management throughout a given year.…”

“…NH 3 emissions from livestock occur during animal housing, manure storage, spreading, and grazing, though the latter phase is relatively negligible, considering the intensive level of farming in northern Italy. The contribution of NH 3 emissions to the formation of secondary particulate matter is highlighted for the Po Basin by different studies [16,17].…”

Assessing the impacts and feasibility of emissions reduction scenarios in the Po Valley

“…The NINFA-ER CTM simulation as mentioned in (Veratti et al, 2023), utilized the 2017 emission dataset of LIFE-IP PREPAIR based on the collection of all the data of the INEMAR system and of the data available for the areas not covered by this database relatively to Slovenia and other areas not covered by the system. However, it is not worth noting that a more recent emission inventory referring to 2019 has been managed for Lombardy Region.…”

“…emission inventory data and (Veratti et al, 2023) for a detailed description of the CHIMERE set-up and domain application.…”