Characterisation of Aerosols Using Carbon and Lead Stable Isotopes and Trace Elements.

Cutajar, Josephine-Anne (1997). Characterisation of Aerosols Using Carbon and Lead Stable Isotopes and Trace Elements. PhD thesis The Open University.

DOI: https://doi.org/10.21954/ou.ro.0000f5ef

Abstract

Ambient air contains a multitude of solid particles in a wide grain size range, commonly referred to as atmospheric aerosol. Aerosols can be inserted into the atmosphere by a large number of processes, including water bubble bursting and wind injection, and can be derived from a numerous sources, including incinerators, smelters, vehicles, sea and soil/crust. Trace element characteristics have been used extensively to identify anthropogenic components within the atmosphere. However, methods such as enrichment factors and principal component analysis can crudely discriminate between various sources of an element such as Pb. C and Pb isotopes have been found to have potential for the identification and characterisation of aerosol sources. Thus, when trace element characteristics and C and Pb stable isotopes ore used in conjunction the sources of elements may be characterised.

Aerosol samples were collected from two locations in the United Kingdom. The first at Milton Keynes consisted of a one year monitoring programme; the second in the South Wales region covered a broader geographic area in the hope of identifying discreet source areas. The aerosols were analysed for their Pb isotopic compositions, ð¹³C values and trace element abundance.

At Milton Keynes, ð¹³C Pb isotopic compositions and trace element abundance were found to vary considerable depending on wind direction, indicating multiple sources. At least three sources have been identified; vehicles, soils and point sources, such as incinerators. Aerosol Pb and trace element abundance were found to be influenced by rainfall, with rain having an apparent scavenging effect on Pb in the atmosphere. Temporal flucuations, both daily to montly, have been associated with these weather conditions.

Within the S Wales region two preliminary source zones of C and Pb were identified, with a possible third mixing zone; marine, industrial and rural/marine. Upon further investigation these sources were sufficiently honed to characterise three source areas with two mixing zones;

(1) Rural

(2) Industrial

(3) Marine

(4) Industrial/Marine mix

(5) Vehicle/Marine mix

These zones were found to be wind direction dependent and did not alter annually.