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Quantifying primary and secondary source contributions to ultrafine particles in the UK urban background

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journal contribution
posted on 02.08.2017, 13:37 by S. M. L. Hama, R. L. Cordell, P. S. Monks
Total particle number (TNC, ≥7 nm diameter), particulate matter (PM 2.5 ), equivalent black carbon (eBC) and gaseous pollutants (NO, NO 2 , NOx, O 3 , CO) have been measured at an urban background site in Leicester over two years (2014 and 2015). A derived chemical climatology for the pollutants showed maximum concentrations for all pollutants during the cold period except O 3 which peaked during spring. Quantification of primary and secondary sources of ultrafine particles (UFPs) was undertaken using eBC as a tracer for the primary particle number concentration in the Leicester urban area. At the urban background site, which is influenced by fresh vehicle exhaust emissions, TNC was segregated into two components, TNC = N1 + N2. The component N1 represents components directly emitted as particles and compounds which nucleate immediately after emission. The component N2 represents the particles formed during the dilution and cooling of vehicle exhaust emissions and by in situ new particle formation (NPF). The values of highest N1 (49%) were recorded during the morning rush hours (07:00–09:00 h), correlating with NOx, while the maximum contribution of N2 to TNC was found at midday (11:00–14:00 h), at around 62%, correlated with O 3 . Generally, the percentage of N2 (57%) was greater than the percentage of N1 (43%) for all days at the AURN site over the period of the study. For the first time the impact of wind speed and direction on N1 and N2 was explored. The overall data analysis shows that there are two major sources contributing to TNC in Leicester: primary sources (traffic emissions) and secondary sources, with the majority of particles being of secondary origin.

Funding

The authors would like to thank the Human Capacity Development Program from the Kurdistan Government for a scholarship (S.M.L.HAMA). We would like to thank Dr.Sergio Rodríguez to his help and suggestions. We would like also to thank Dr Jolanta Obszynska (Leicester City Council) for providing meteorological data. This research was funded by the Joint Air Quality Initiative (JOAQUIN) project, part of the EU Interreg IV-B NWE Program.

History

Citation

Atmospheric Environment, 2017, 166, pp. 62-78

Author affiliation

/Organisation/COLLEGE OF SCIENCE AND ENGINEERING

Version

AM (Accepted Manuscript)

Published in

Atmospheric Environment

Publisher

Elsevier

issn

1352-2310

eissn

1873-2844

Acceptance date

04/07/2017

Copyright date

2017

Available date

05/07/2018

Publisher version

http://www.sciencedirect.com/science/article/pii/S1352231017304545?via=ihub

Notes

The file associated with this record is under embargo until 12 months after publication, in accordance with the publisher's self-archiving policy. The full text may be available through the publisher links provided above.;Supplementary data related to this article can be found at http:// dx.doi.org/10.1016/j.atmosenv.2017.07.013.

Language

en