Carbonaceous PM10 and PM2.5 and secondary organic aerosol in a coastal rural site near Brindisi (Southern Italy)

Abstract

Organic and elemental carbon were measured both in daily PM10 and PM2.5 and in 6 h range time PM2.5 samples collected from September 2015 to October 2015 in a coastal rural site near Brindisi in the Apulia region (Italy), in order to determine factors affecting the carbonaceous aerosol variations. Carbon content (total carbon TC) represented a considerable fraction for both PM10 and PM2.5. In particular, in PM10 samples, organic carbon (OC) varied from 1.06 to 18.32 μg m with a mean concentration of 5 ± 4 μg m and EC varied from 0.11 to 0.88 μg m with a mean value of 0.41 ± 0.19 μg m. In PM2.5 samples, OC varied from 0.54 to 12.91 μg m with a mean concentration of 3.5 ± 2.8 μg m and EC varied from 0.11 to 0.85 μg m with a mean value of 0.35 ± 0.18 μg m. The highest values for both parameters were recorded when the air masses were coming from NE Europe and when Saharan Dust events were recognized. The results show that OC and EC exhibited higher concentrations during the night hours, suggesting that stable atmosphere and lower mixing conditions play important roles for the accumulation of air pollutants and promote condensation or adsorption of semivolatile organic compounds. In samples from a Saharan Dust event and in samples with the lowest and the highest OC, ATR-FTIR analysis allowed us to identify organic functional groups including the non-acid organic hydroxyl C-OH group (e.g., sugars, anhydrosugars, and polyols), carbonyl C=O group, carboxylic acid COOH group, aromatic and aliphatic unsaturated C=C-H group, aliphatic saturated C-C-H group, and amine NH group. Some inorganic ions were also identified: carbonates, sulfate, silicate, and ammonium. The dusty samples are mainly characterized by the presence of carbonate and hydrogen sulfate ions and by kaolinite (absorption at 914 and 1010 cm), while in samples with air masses coming from the NE, OC is mainly characterized by aliphatic and aromatic C-H and O-H and N-H groups (absorptions in the range 3500-2700 cm) and by the presence of organonitrate, aromatic amide and amine, and carboxylic acids (absorptions at 1630 and 1770-1700 cm). Graphical abstract ᅟ.

Air quality at two stations (Gdynia and Rumia) located in the region of Gulf of Gdansk during periods of intensive smog in Poland

“…The OC/ EC coefficient, in PM10 measured in Rumia ranged from 2.4 to 24.4, indicates the source of carbon origin. These values and their amplitude were much higher than those obtained in smaller aerosols collected in Gdynia (between 1.4 and 5.9 in PM1 and between 1.2 and 6.1 in PM2.5) (Pio et al 2008;Siciliano et al 2018). This may indicate that, in Gdynia in PM1 and PM2.5, the share of carbon originating from communication sources was higher than in PM10 in Rumia (Keuken et al 2013).…”

“…Differences in the origin of carbon in aerosols at the two measuring stations are confirmed by a better correlation between OC and EC obtained in smaller aerosols in Gdynia (r = 0.96 for PM2.5 and r = 0.95 for PM1) than in PM10 in Rumia (r = 0.87). The highest OC/ EC values were determined in PM10 in Rumia, and this, along with a lower correlation between the two carbonaceous compounds, indicates the greater role of secondary organic carbon in this city than in Gdynia (Siciliano et al 2018). This in turn suggests that combustion for heating purposes may be the main pollution source in Rumia (Witkowska et al 2016a).…”

Accumulation and coarse mode aerosol concentrations and carbonaceous contents in the urban background atmosphere in Amman, Jordan

“…According to the ATR-FTIR analysis, the spectra showed three interesting major signals (Fig. 7) for carbon containing compounds that are emitted from fossil fuel combustion such as traffic tailpipe emissions (e.g., Siciliano et al 2018;Popovicheva et al 2017;Shaltout et al 2016;Agudelo-Castañeda et al 2015;Popovicheva et al 2015;Jiang et al 2011). The first signal (wave number 800-1100 cm −1 ; mass fraction 37.1-45.6%) represents polycyclic aromatic hydrocarbon compounds that contain functional groups such as sulfur, hydroxyl, or ester.…”

A Mechanism for the Adsorption of 2-(Hexadecanoylamino)Acetic Acid by Smithsonite: Surface Spectroscopy and Microflotation Experiments

“…Spectrum (a) is that of HAA in the 500-4000 cm −1 range: This spectrum exhibited peaks at 3327 cm −1 due to the stretching vibrations of the N-H bond, at 2918 and 2849 cm −1 that corresponded to the C-H stretches of -CH 3 and -CH 2 units, and at 1703 cm −1 , which was assigned to the C=O bond of the carboxylic acid moiety in the collector molecule [27,28]. The peaks at 1645 cm −1 and 1559 cm −1 were assigned to amide I and II vibrations: Amide I arose from the C=O stretch, while the amide II band was mostly due to N-H and C-H vibrations [29][30][31][32]; peaks that appeared at 1472 and 719 cm −1 were representative of C-H bending; and C-N and C-O stretching bands were observed at 1272 and 1037 cm −1 , respectively [33][34][35].…”