Studies of the properties of particulate matter in the UK atmosphere

Laongsri, Bunthoon (2013). Studies of the properties of particulate matter in the UK atmosphere. University of Birmingham. Ph.D.

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Abstract

The studies on physical and chemical properties of airborne particulate matter were carried out in the UK atmosphere. Aerosol samples were collected at the Elm Road Observatory Site and Harwell representing urban background and rural area, respectively. The chemical components of both PM\(_2\)\(_.\)\(_5\) and PM\(_2\)\(_.\)\(_5\)\(_-\)\(_1\)\(_0\) were mainly analysed for carbonaceous compounds, sulphate, nitrate, chloride and oxalate. Size distributions of aerosol components were investigated in conjunction with the study of ammonia gas to stabilise the semivolatile species in atmospheric particles. Concentration composition of carbonaceous compounds (organic and elemental carbon - OC and EC) in particulate matter clearly observed higher value at urban background than those at rural area. The OC/EC minimum ratio of 0.35 was used to distinguish between primary and secondary OC as EC was a good indicator of primary sources. Sulphate and nitrate showed the good relationship, indicating that two species undergo similar formation and removal processes in atmosphere. Chloride was commonly originated from marine aerosol with the weak correlation observed with other major species. Oxalate is highly focused specie in this study as there is rarely available data in the UK. The good correlation and the similar pattern of size distribution between oxalate and sulphate suggest that their formation pathway formed from the same atmospheric processes. The excess ammonia gas supplied during the air sampling could be stablilsed and yielded the higher concentrations of nitrate and chloride which were expected in the forms of ammonium salts. In contrast, oxalate in ambient air was exhibited the discordant behaviour in this experiment. Our trajectory analysis suggests the important precursor sources of oxalate were from continental area associated with the high atmospheric pollutants.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

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