Lung deposited surface area in Leicester urban background site/UK: Sources and contribution of new particle formation

Abstract

Highlights 15• Clear seasonal variation of Lung Deposited Surface Area (LDSA) concentrations is 16 observed with higher values in winter. 17• Calculated LDSA seems to be a good surrogate to equivalent black carbon mass 18 concentration. 19• Traffic emissions appear to be the main source of LDSA in Leicester. 20• LDSA concentrations are nearly doubled during new particle formation episodes. Lung Deposited Surface Area (LDSA) has been identified as a potential metric for the 2 correlation of a physical aerosol particle properties with health outcomes. Currently, there is 3 little urban LDSA data. As a case study, we investigated measurements of LDSA (alveolar) 4 concentrations in a mid-size European city. LDSA and associated measurements were carried 5 out over 1.5 years at an urban background site in Leicester, UK. Average LDSA concentrations 6 in the cold (November-April) and warm (May-October) seasons of UK were 37 and 23 µm 2 7 cm -3 , respectively. LDSA correlates well (R 2 =0.65-0.7, r=0.77-0.8) with traffic related 8 pollutants, such as equivalent black carbon (eBC) and NOX. We also report for the first time in 9 the UK the correlation between an empirically derived LDSA and eBC. Furthermore, the effect 10 of wind speed and direction on the LDSA was explored. Higher LDSA concentrations are 11 observed at low wind speeds (1-2 m s -1 ), owing to local traffic emissions. In addition, the diurnal 12 variation of LDSA showed a second peak in the afternoon under warm and relatively clean 13 atmospheric conditions, which can be attributed to photochemical new particle formation (NPF) 14 and growth into the Aitken mode range. These NPF events increased the average background 15 LDSA concentrations from 15.5 to 35.5 µm 2 cm -3 , although they might not be health-relevant. 16Overall, the results support the notion that local traffic emissions are a major contributor to 17 observed LDSA concentrations with a clear seasonal pattern with higher values during winter.

Long-term sensor measurements of lung deposited surface area of particulate matter emitted from local vehicular and residential wood combustion sources

“…Similar results have been observed previously by, e.g. Hama et al (2017), Eeftens et al (2015) and Reche et al (2015). Instead, the correlation between the LDSA and PM 2.5 was poor.…”

“…PM 2.5 ) measurements. Single measurements of LDSA have been conducted previously in different ambient environments, for example, in Barcelona (Reche et al 2015), Leicester (Hama et al 2017), and Ruhr (Hennig et al 2018) but to our knowledge there are no urban sensor network studies demonstrating the utilization of diffusion charged-based sensors to measurements of LDSA.…”

Sub-micron particle number size distribution characteristics at two urban locations in Leicester

“…Sampling was conducted during the spring (March-June 2014) at two sites located at the University of Leicester (Figure 1). More detailing about the characteristics and locations of the sampling sites can be found in Hama et al (2017). In this study hourly traffic density data was provided by Leicester City Council was used.…”

“…The reference method for the determination of concentrations of O3 are described in European Standard EN14625, more information can be found in this website (https://ukair.defra.gov.uk/networks/monitoring-methods?view=eu-standards). For a detailed overview of the instruments and monitors that were used in this study and also about data quality assurance in the JOAQUIN project, the reader is referred to Hama et al (2017).…”

“…This study reports on the first results of PNSD measurements which were taken as part of the air quality monitoring network established across North West Europe as part of the JOint Air QUality INitiative (JOAQUIN, www.joaquin.eu), an INTERREG IVB funded European project, which aims at supporting health-oriented air quality policies in North-West Europe. More information can be found in the Joaquin report and publications (Joaquin, 2015;Cordell et al, 2016;Hama et al, 2017).…”