Ambient carbonaceous aerosol levels in Cyprus and the role of pollution transport from the Middle East

Abstract

Abstract. The geographical origin and source apportionment of submicron carbonaceous aerosols (organic aerosols, OAs, and black carbon, BC) have been investigated here for the first time, deploying high time-resolution measurements at an urban background site of Nicosia, the capital city of Cyprus, in the eastern Mediterranean. This study covers a half-year period, encompassing both the cold and warm periods with continuous observations of the physical and chemical properties of PM1 performed with an Aerosol Chemical Speciation Monitor (ACSM), an aethalometer, accompanied by a suite of various ancillary offline and online measurements. Carbonaceous aerosols were dominant during both seasons (cold and warm periods), with a contribution of 57 % and 48 % to PM1, respectively, and exhibited recurrent intense nighttime peaks (> 20–30 µg m−3) during the cold period, associated with local domestic heating. The findings of this study show that high concentrations of sulfate (close to 3 µg m−3) were continuously recorded, standing among the highest ever reported for Europe and originating from the Middle East region. Source apportionment of the OA and BC fractions was performed using the positive matrix factorization (PMF) approach and the combination of two models (aethalometer model and multilinear regression), respectively. Our study revealed elevated hydrocarbon-like organic aerosol (HOA) concentrations in Nicosia (among the highest reported for a European urban background site), originating from a mixture of local and regional fossil fuel combustion sources. Although air masses from the Middle East had a low occurrence and were observed mostly during the cold period, they were shown to strongly affect the mean concentrations levels of BC and OA in Nicosia during both seasons. Overall, the present study brings to our attention the need to further characterize primary and secondary carbonaceous aerosols in the Middle East, an undersampled region characterized by continuously increasing fossil fuel (oil and gas) emissions and extreme environmental conditions, which can contribute to photochemical ageing.

Submicron Aerosol Pollution in Greater Cairo (Egypt): A New Type of Urban Haze?

“…The concentrations of organic aerosols (OA) are also compared to the OC levels determined on PM 1 filters. An excellent agreement is also found here (R 2 = 0.89), with a slope of 1.6, similar to the one used to reconstruct chemically the PM 1 mass, and being close to the values reported by Christodoulou et al (2023) for Nicosia (Cyprus) during wintertime and OM/OC calculations from AMS measurements in polluted environments (Saarikoski et al, 2012).…”

“…The corresponding parameters, response factor (RF), and relative ionization efficiency (RIE) are reported in Table S1. More details about the Q-ACSM setup, operation, and QA/QC protocol used here can be found in Christodoulou et al (2023).…”

“…The EMME experiences enhanced regional background pollution levels, particularly during summer, leading to exceedances of ozone and PM thresholds (Gerasopoulos et al, 2006;Kanakidou et al, 2011;Kleanthous et al, 2014). Therefore, air quality in EMME cities is not only impacted by local emissions but also by its regional background levels (e.g., Christodoulou et al, 2023) and intense pollution episodes emanating from distant sources. Eventually, the adverse health impact of air pollution in EMME cities may also be amplified by extreme weather events (e.g., heat waves).…”

Enhanced light absorption by ambient brown carbon aerosols in the eastern Himalayas

“…Carbonaceous aerosols (CA), which consist of organic carbon (OC) and elemental carbon (EC), are pervasive in the atmosphere. They are modulated by distinct origins either natural or anthropogenic, 1,2 which lead to complex interactions (scattering or absorption) with the solar radiation, and alter the energy balance of the Earth system. 3,4 CA also play a critical role in the formation of clouds via acting as cloud condensation nuclei and ice nuclei.…”