Polycyclic aromatic hydrocarbons (PAHs) and their alkylated, nitrated and oxygenated derivatives in the atmosphere over the Mediterranean and Middle East seas

• Published in: Atmospheric chemistry and physics Vol. 22; no. 13; pp. 8739 - 8766
• Main Authors: Wietzoreck, Marco, Kyprianou, Marios, Musa Bandowe, Benjamin A, Celik, Siddika, Crowley, John N, Drewnick, Frank, Eger, Philipp, Friedrich, Nils, Iakovides, Minas, Kukucka, Petr, Kuta, Jan, Nežiková, Barbora, Pokorná, Petra, PÅibylová, Petra, ProkeÅ¡, Roman, Rohloff, Roland, Tadic, Ivan, Tauer, Sebastian, Wilson, Jake, Harder, Hartwig, Lelieveld, Jos, Pöschl, Ulrich, Stephanou, Euripides G, Lammel, Gerhard
• Format: Journal Article
• Language: English
• Published: Katlenburg-Lindau Copernicus GmbH 07-07-2022; Copernicus Publications
• Subjects: 2-Nitropyrene; Air; Air pollution; Air quality; Air-sea interaction; Alkylation; Anthracene; Anthraquinone; Anthraquinones; Aromatic compounds; Aromatic hydrocarbons; Atmosphere; Atmospheric transport; Climate change; Emissions; Exhaust emissions; Global temperature changes; Oil pollution; Outdoor air quality; Oxygenation; Particulate emissions; Particulate matter; Photochemicals; Photochemistry; Pollutants; Polycyclic aromatic hydrocarbons; Polyethylene; Research ships; Shipping; Suspended particulate matter; Mediterranean Sea; Czech Republic; United States > US; Red Sea; Arabian Sea; Suez Canal; Kuwait
• ISSN: 1680-7324; 1680-7316; 1680-7324
• DOI: 10.5194/acp-22-8739-2022

Polycyclic aromatic hydrocarbons (PAHs) and their alkylated
(RPAHs), nitrated (NPAHs) and oxygenated (OPAHs) derivatives are air
pollutants. Many of these substances are long-lived, can undergo long-range
atmospheric transport and adversely affect human health upon exposure.
However, the occurrence and fate of these air pollutants have hardly been
studied in the marine atmosphere. In this study, we report the atmospheric
concentrations over the Mediterranean Sea, the Red Sea, the Arabian Sea, the
Gulf of Oman and the Arabian Gulf, determined during the AQABA (Air Quality
and Climate Change in the Arabian Basin) project, a comprehensive ship-borne
campaign in summer 2017. The average concentrations of ∑26PAHs,
∑19RPAHs, ∑11OPAHs and ∑17NPAHs, in the gas
and particulate phases, were 2.99 ± 3.35 ng m−3, 0.83 ± 0.87 ng m−3, 0.24 ± 0.25 ng m−3 and 4.34 ± 7.37 pg m−3, respectively. The Arabian Sea region was the cleanest for all
substance classes, with concentrations among the lowest ever reported. Over
the Mediterranean Sea, we found the highest average burden of ∑26PAHs and ∑11OPAHs, while the ∑17NPAHs were
most abundant over the Arabian Gulf (known also as the Persian Gulf).
1,4-Naphthoquinone (1,4-O2NAP) followed by 9-fluorenone and
9,10-anthraquinone were the most abundant studied OPAHs in most samples. The
NPAH composition pattern varied significantly across the regions, with
2-nitronaphthalene (2-NNAP) being the most abundant NPAH. According to
source apportionment investigations, the main sources of PAH derivatives in
the region were ship exhaust emissions, residual oil combustion and
continental pollution. All OPAHs and NPAHs except 2-nitrofluoranthene (2-NFLT), which were
frequently detected during the campaign, showed elevated concentrations in
fresh shipping emissions. In contrast, 2-NFLT and
2-nitropyrene (2-NPYR) were highly abundant in aged shipping emissions due
to secondary formation. Apart from 2-NFLT and 2-NPYR,
benz(a)anthracene-7,12-dione and 2-NNAP also had significant photochemical
sources. Another finding was that the highest concentrations of PAHs, OPAHs
and NPAHs were found in the sub-micrometre fraction of particulate matter
(PM1).