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Light-absorbing aerosols (LAA) impact the atmosphere by heating it. Their effect in the Arctic was investigated during two summer Arctic oceanographic campaigns (2018 and 2019) around the Svalbard Archipelago in order to unravel the differences between the Arctic background and the local anthropic settlements. Therefore, the LAA heating rate (HR) was experimentally determined. Both the chemical composition and high-resolution measurements highlighted substantial differences between the Arctic Ocean background (average eBC concentration of 11.7 ± 0.1 ng/m3) and the human settlements, among which the most impacting appeared to be Tromsø and Isfjorden (mean eBC of 99.4 ± 3.1 ng/m3). Consequently, the HR in Isfjorden (8.2 × 10−3 ± 0.3 × 10−3 K/day) was one order of magnitude higher than in the pristine background conditions (0.8 × 10−3 ± 0.9 × 10−5 K/day). Therefore, we conclude that the direct climate impact of local LAA sources on the Arctic atmosphere is not negligible and may rise in the future due to ice retreat and enhanced marine traffic.

La tesi esplora le correlazioni fra composizione chimica del particolato emesso in frenata e alcuni fattori quali: i) le combinazioni di materiali che compongono l'interfaccia tribologica; ii) le condizioni di guida; iii) le frazioni dimensionali in cui vengono prodotti i particolati, This thesis reports on the correlations between the compositional features of the particulates produced by brakes and several determining or modulating factors, such as: i) The starting material composing the friction couple; ii) the driving conditions; and iii) the dimensional fractions in which the particulates are generated and emitted.

Biomass burning related aerosol episodes are becoming a serious threat to the radiative balance of the Arctic region. Since early July 2017 intense wildfires were recorded between August and September in Canada and Greenland, covering an area up to 4674 km2 in size. This paper describes the impact of these biomass burning (BB) events measured over Svalbard, using an ensemble of ground-based, columnar, and vertically-resolved techniques. BB influenced the aerosol chemistry via nitrates and oxalates, which exhibited an increase in their concentrations in all of size fractions, indicating the BB origin of particles. The absorption coefficient data (530 nm) at ground reached values up to 0.6 Mm-1, highlighting the impact of these BB events when compared to average Arctic background values, which do not exceed 0.05 Mm-1. The absorption behavior is fundamental as implies a subsequent atmospheric heating. At the same time, the AERONET Aerosol Optical Depth (AOD) data showed high values at stations located close to or in Canada (AOD over 2.0). Similarly, increased values of AODs were then observed in Svalbard, e.g., in Hornsund (daily average AODs exceeded 0.14 and reached hourly values up to 0.5). Elevated values of AODs were then registered in Sodankyla and Andenes (daily average AODs exceeding 0.150) a few days after the Svalbard observation of the event highlighting the BB columnar magnitude, which is crucial for the radiative impact. All the reported data suggest to rank the summer 2017 plume of aerosols as one of the biggest atmosphere related environmental problems over Svalbard region in last 10 years.

Biomass burning related aerosol episodes are becoming a serious threat to the radiative balance of the Arctic region. Since early July 2017 intense wildfires were recorded between August and September in Canada and Greenland, covering an area up to 4674 km2 in size. This paper describes the impact of these biomass burning (BB) events measured over Svalbard, using an ensemble of ground-based, columnar, and vertically-resolved techniques. BB influenced the aerosol chemistry via nitrates and oxalates, which exhibited an increase in their concentrations in all of size fractions, indicating the BB origin of particles. The absorption coefficient data (530 nm) at ground reached values up to 0.6 Mm–1, highlighting the impact of these BB events when compared to average Arctic background values, which do not exceed 0.05 Mm–1. The absorption behavior is fundamental as implies a subsequent atmospheric heating. At the same time, the AERONET Aerosol Optical Depth (AOD) data showed high values at stations located close to or in Canada (AOD over 2.0). Similarly, increased values of AODs were then observed in Svalbard, e.g., in Hornsund (daily average AODs exceeded 0.14 and reached hourly values up to 0.5). Elevated values of AODs were then registered in Sodankylä and Andenes (daily average AODs exceeding 0.150) a few days after the Svalbard observation of the event highlighting the BB columnar magnitude, which is crucial for the radiative impact. All the reported data suggest to rank the summer 2017 plume of aerosols as one of the biggest atmosphere related environmental problems over Svalbard region in last 10 years

Questo studio si focalizza sulla concentrazione e sul comportamento di composti organici in atmosfera nella Regione Lombardia, un'area critica per l'inquinamento atmosferico, e nel Mare del Nord. L'attenzione sarà incentrata su composti potenzialmente tossici per la salute umana (come gli idrocarburi policiclici aromatici - IPA) e composti che possono fornire informazioni sulle sorgenti di emissione (come gli alcani). La corretta identificazione delle sorgenti dell’inquinamento consente di progettare strategie di abbattimento adeguate per migliorare la qualità dell'aria. I campioni, sia in fase particolata che in fase gassosa, raccolti a Milano sono stati analizzati per studiare la ripartizione di fase di IPA semi-volatili e di alcani lineari in diverse stagioni. Poiché una delle fonti più importanti del particolato in Lombardia durante tutto l'anno è costituita dalle emissioni autoveicolari, è stato effettuato un confronto tra le concentrazioni e la composizione chimica del particolato raccolto a Milano, in due siti con carichi di traffico diversi, al fine di valutare l'effetto della zona a traffico limitato (ZTL). Oltre alle emissioni autoveicolari, le emissioni relative alle attività aeroportuali hanno destato grande interesse negli ultimi anni; l'aviazione civile è, infatti, uno dei settori in più rapida crescita dell'economia globale. In Lombardia si trova l'aeroporto internazionale di Milano-Malpensa che rappresenta il principale aeroporto del nord Italia e il secondo aeroporto italiano per traffico passeggeri dopo quello di Roma-Fiumicino. All'interno dell'aeroporto è stata realizzata una campagna di campionamento per studiare il contributo delle attività aeroportuali alle emissioni dei principali inquinanti atmosferici e valutare l'impatto di queste attività sui comuni dell'area circostante. L'inquinamento atmosferico, tuttavia, è un problema che non riguarda solo i siti urbani; gli inquinanti possono, infatti, essere trasportati su lunghe dista, This study is focused on the atmospheric concentration and the behavior of specific organic compounds in the Lombardy Region, a critical area for atmospheric pollution, and in the North Sea. The attention will be focused on compounds that are potentially toxic for human health (such as Polycyclic Aromatic Hydrocarbons- PAHs) and that can give information on their emission source (such as alkanes). The correct identification of the anthropogenic pollutant sources would allow to design suitable abatement strategies to improve the air quality. Samples of atmospheric particulate and gaseous phases collected in Milan were analyzed to study the atmospheric gas/particle partitioning of semi-volatile PAHs and n-alkanes in different seasons. Since one of the most important source of the particulate matter in Lombardy Region during all the year is vehicle exhausts, a comparison between the concentrations and the chemical composition of particulate matter collected in Milan, at two sites with different traffic loads, was performed for the purpose of evaluating the effect of the Low Emission Zone. In addition to car exhausts, emissions related to airport activities aroused great interest in recent years since civil aviation is one of the fastest-growing sectors of the global economy. In the Lombardy region is located the international airport of Milan-Malpensa that represents the main airport of northern Italy and the second Italian airport for passenger traffic after that of Rome-Fiumicino. A sampling campaign was performed inside the airport, in order to study the contribution of airport activities to the emissions of the main atmospheric pollutants and to assess the impact of these activities on the surrounding area. Air pollution, however, is a problem not only for urban sites; pollutants can, in fact, be transported over long distances and thus contribute to the air pollution of remote sites. The study of atmospheric pollutants in remote sites can provide information on th

Light absorbing aerosols (LAA) absorb sunlight and heat the atmosphere. This work presents a novel methodology to experimentally quantify the heating rate (HR) induced by LAA into an atmospheric layer. Multiwavelength aerosol absorption measurements were coupled with spectral measurements of the direct, diffuse and surface reflected radiation to obtain highly time-resolved measurements of HR apportioned in the context of LAA species (black carbon, BC; brown carbon, BrC; dust), sources (fossil fuel, FF; biomass burning, BB), and as a function of cloudiness. One year of continuous and time-resolved measurements (5 min) of HR were performed in the Po Valley. We experimentally determined (1) the seasonal behavior of HR (winter 1.83 ± 0.02 K day-1; summer 1.04 ± 0.01 K day-1); (2) the daily cycle of HR (asymmetric, with higher values in the morning than in the afternoon); (3) the HR in different sky conditions (from 1.75 ± 0.03 K day-1 in clear sky to 0.43 ± 0.01 K day-1 in complete overcast); (4) the apportionment to different sources: HRFF (0.74 ± 0.01 K day-1) and HRBB (0.46 ± 0.01 K day-1); and (4) the HR of BrC (HRBrC: 0.15 ± 0.01 K day-1, 12.5 ± 0.6% of the total) and that of BC (HRBC: 1.05 ± 0.02 K day-1; 87.5 ± 0.6% of the total).