Quantification of volatile organic compounds in cities in the UK and Africa

This work centred on the analysis of non-methane volatile organic compounds (NMVOCs) in the ambient atmosphere from selected sites in Leicester city (Europe) and Lagos city (Africa). In Leicester, it was observed that vehicular emission was a major contributor to the NMVOCs, while Lagos had in addition to vehicular emissions, there were alternative sources such as industrial emission, and other anthropogenic activities. The impact of covid 19 lockdown on the United Kingdom environment, was considered to ascertain the prevalence and variation of non-methane volatile organic compounds load in the atmosphere and the ozone formation potential of the NMVOC was explored. During lockdown in contrast to the other compounds, ozone (O₃) increased while NO₂ and NMVOCs from regular anthropogenic sources decreased. All measurement in this study were within EU regulatory limit during the lockdown, but benzene was slightly above the 5 μg/m3 annual average limit for pre-lockdown and post-lockdown periods.

Chemical ionization reaction mass spectrometry (CIR-MS) was used to determine the total volatile organic compounds present in the Leicester atmosphere with oxygen as the reagent ion (O₂⁺) for the purpose of ascertaining, quantifying and development of method for calculating the total volatile organic carbon in the atmosphere. The total volatile organic carbon calculation for n-alkane (C₂− C₉) and aromatic hydrocarbon revealed that n-alkanes had fragments of m/z < 72 and the aromatics had fragments > 77 so the estimate of organic carbon could be calculated as a group contribution with a spread of about 13 % to 30 %.

This thesis will aim to examine, identify, and ascertain the prevalence and variation of NMVOCs and the impact of Covid 19 on the atmosphere and develop a method for the calculation of total organic carbon in the atmosphere from selected NMVOCs.