Determination of total and lung-deposited particle surface area concentrations, in central Athens, Greece Stavros Cheristanidis & Georgios Grivas & Archontoula Chaloulakou Received: 10 January 2020 /Accepted: 24 August 2020 # Springer Nature Switzerland AG 2020 Abstract Numerous health studies have linked the ex- posure to particulate matter with adverse health effects, while there is an increasing scientific interest in the particle metrics of surface area (SA) and lung- deposited SA (LDSA) concentration. In the present study, two integrated SA estimation methods, both based on widely used instrumentation, were applied at an urban traffic environment in Athens for a 6-month period. The first estimation method used the size distri- bution by number to estimate SA (average SA 1 669.3 ± 229.0 μm 2 cm −3 ), while the second method used a simple inversion scheme that incorporates number and mass concentrations (average SA 2 1627.9 ± 562.8 μm 2 cm −3 ). In pairwise comparisons, SA 2 levels were found two times greater than the corresponding SA 1 , but ex- hibited a strong correlation (r = 0.73). SA 1 and SA 2 concentrations correlated well with the traffic-related pollutants NO x (r = 0.64 and 0.78) and equivalent black carbon (r = 0.53 and 0.51). The diurnal variation of SA 1 concentrations by size range indicated traffic as a major controlling factor. Estimated LDSA (53.9 μm 2 cm −3 on average) concentrations were also clearly affected by anthropogenic emissions with more pronounced associ- ations in the 0.01–0.4 μm range (r = 0.66 with NO x and r = 0.65 with equivalent black carbon). Validating esti- mated LDSA through simultaneous measurements with a reference instrument revealed that the estimation method underestimates LDSA by a factor between 2 and 3, exhibiting, however, a high correlation (r = 0.79). Overall, the performance of estimation methods appear satisfactory and indicate that a trustworthy as- sessment of the temporal variability of SA and LDSA concentration metrics can be provided in real time, on the basis of relatively lower-cost instrumentation, espe- cially in view of recent advances in particle sensing technologies. Keywords Surface area . Lung deposit SA . Estimation methods . Urban air pollution Introduction A large number of epidemiological studies, conducted around the world, have associated the exposure to am- bient aerosols with public health issues (Dockery et al. 1993; Pope et al. 1995; IARC 2013). Particulate matter (PM) appears to be the ambient pollutant most consis- tently linked with adverse health outcomes related to morbidity and mortality (Hoek et al. 2013; Di et al. 2017). While studies all over the world have associated the exposure in high levels of suspended particles with both long-term and short-term effects on human health (Katsouyanni et al. 2009; Ostro et al. 2015; Mulenga Environ Monit Assess (2020) 192:627 https://doi.org/10.1007/s10661-020-08569-8 S. Cheristanidis (*) : A. Chaloulakou School of Chemical Engineering, National Technical University of Athens, 15780 Zografos, Athens, Greece e-mail: stavrher@mail.ntua.gr G. Grivas Institute for Environmental Research and Sustainable Development, National Observatory of Athens, 15236 Athens, Greece