University of Hertfordshire

Trends of atmospheric black carbon concentration over United Kingdom

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Original languageEnglish
Number of pages10
Pages (from-to)148–157
JournalAtmospheric Environment
Journal publication date1 Apr 2018
Volume178
Early online date31 Jan 2018
DOIs
Publication statusPublished - 1 Apr 2018

Abstract

The continuous observations over a period of 7 years (2009–2016) available at 7 locations show declining trend of atmospheric BC in the UK. Among all the locations, the highest decrease of 8 ± 3 percent per year was observed at the Marylebone road in London. The detailed analysis performed at 21 locations during 2009–2011 shows that average annual mean atmospheric BC concentration were 0.45, 1.47 ± 0.58, 1.34 ± 0.31, 1.83 ± 0.46 and 9.72 μgm−3 at rural, suburban, urban background, urban centre and kerbside sites respectively. Around 1 μgm−3 of atmospheric BC could be attributed to urban emission, whereas traffic contributed up to 8 μgm−3 of atmospheric BC near busy roads. Seasonal pattern was also observed at all locations except rural
and kerbside location, with maximum concentrations (1.2–4 μgm−3) in winter. Further, minimum concentrations (0.3–1.2 μgm−3) were observed in summer and similar concentrations in spring and fall. At suburban and
urban background locations, similar diurnal pattern were observed with atmospheric BC concentration peaks (≈1.8 μgm−3) in the morning (around 9 a.m.) and evening (7–9 p.m.) rush hours, whereas minimum concentrations
were during late night hours (peak at 5 a.m.) and the afternoon hours (peak at 2 p.m.). The urban centre values show a similar morning pattern (peak at 9 a.m.; concentration - 2.5 μgm−3) in relation to background
locations but only a slight decrease in concentration in the afternoon which remained above 2 μgm−3 till midnight. It is concluded that the higher flow of traffic at urban centre locations results in higher atmospheric BC
concentrations throughout the day. Comparison of weekday and weekend daily averaged atmospheric BC showed maximum concentrations on Friday having minimum levels on Sunday. This study will help to refine the
atmospheric BC emission over Europe and also provide inputs for climate change models, which in turn will help policy makers to reduce atmospheric BC emissions, globally.

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