Characteristics of Airborne Nanoparticles during Summertime in Kuwait

263 Pages·2016·7.52 MB·English

Characteristics of Airborne Nanoparticles
during Summertime in Kuwait

by
Abdullah N. Al-Dabbous

A thesis submitted to the University of Surrey, Faculty of Engineering and
Physical Sciences, Department of Civil and Environmental Engineering, in
conformity with the requirements for the degree of Doctor of Philosophy

University of Surrey
Guildford, Surrey, United Kingdom
(July, 2015)

Copyright ©Abdullah N. Al-Dabbous, 2015
Abstract
Airborne nanoparticles have prompted a strong research interest in the scientific community
due to their adverse effects on human health and the environment. However, there is a notable
lack of studies focusing on extreme summertime conditions, where ambient temperatures can
reach ~48 °C, relative humidity falls to its minimum values, and dust events are frequently
encountered. The overall aims of this research are to understand the behaviour and sources of
airborne nanoparticles in hot and arid environmental conditions, develop a statistical prediction
model for nanoparticles that uses routinely-monitored air pollutants, and investigate the
mitigation measures (i.e., vegetation barriers) used to limit the penetration of on-road
nanoparticles to the surrounding vicinity.
Size-resolved measurements of particle number distribution (PNDs) and
concentrations (PNCs) were carried out continuously for one month at a roadside location in
the State of Kuwait using a fast-response differential mobility spectrometer (DMS500) to
assess the influence of summertime meteorological conditions on nanoparticles. Further data
of trace pollutants (NO , O , CO, SO and PM ) and meteorological variables (wind speed,
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wind direction, temperature, relative humidity, and solar radiation), were obtained from the
Kuwait Environment Public Authority (KEPA). The collected data was analysed to assess the
behaviour of nanoparticles during summertime and to understand any unusual behaviour of
PNDs and PNCs during (i) the afternoon, when temperature reaches it maximum and relative
humidity to its minimum, and (ii) during the occurrence of Arabian dust events. The collected
PNDs data were used to apportion the major sources and their contribution to total PNCs using
a positive matrix factorisation (PMF) model. Further, a preliminary attempt to predict
nanoparticles in three size ranges (nucleation mode: 5–30 nm, Aitken mode: 30–100 nm, and
accumulation mode: 100–300 nm) using artificial neural network (ANN), was made. For the
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prediction purpose, seven scenarios were considered using different combinations of the
routinely-measured meteorological and trace pollutant data as covariates. In addition,
intermittent monitoring of PNDs and the associated PNCs were performed using DMS50 at a
kerbside location in the United Kingdom (UK) to investigate the effect of vegetation barriers
on traffic-generated nanoparticles, as well as pedestrian exposure. PND data was collected at
four sampling locations pseudo-simultaneously using a multi-probe switching system. These
locations encompassed the vegetation barrier and allowed us to make novel comparisons.
Despite high traffic volumes during noon hours, there was a substantial decrease in
PNCs with a corresponding increase in geometric mean diameters (GMDs) due to high ambient
temperature (∼48 °C) and wind speed (∼15 m s–1). The high wind speed has a dispersive effect
(i.e., dilution), and saltation causes the suspension of particles and enhances the coagulation
process. Based on the PMF modelling, traffic emissions were found to be a major contributor
(73%) to the total apportioned PNCs, whereas Arabian dust transport was found to be the lowest
contributor (3%). ANN succeeded in capturing the general trend between observed and
predicted PNCs with R2 up to 0.79. The deviations between the observed and predicted PNCs
were not substantial, as evidenced by the fact that predicted PNCs were within a factor of two
of the observed PNCs.
Vegetation barriers were found to reduce not only PNCs by ~37%, but also the
associated particle respiratory deposited doses in the human respiratory tract (RDD) by ~36%.
The implication of vegetation barrier results are of high importance in the reduction of PNCs
and the associated RDD. Besides policy makers and environmental authorities, the findings of
this work are important for the modelling community to treat major nanoparticle sources in
dispersion modelling and health impact assessments in the region.
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Acknowledgements
I would like to greatly thank everyone who directly or indirectly had an influence in the
completion of this thesis. I would like to thank my family and friends, especially my parents
and wife for their on-going love, encouragement and for inspiring me to accomplish this task.
Special thanks go to my principal supervisor, Dr Prashant Kumar, for his guidance,
encouragement, consistent supervision and support while undertaken this research. I also thank
my co-supervisor, Professor Alan Robins, for his help and support. I would also like to
acknowledge the Department of Civil and Environmental Engineering (CEE) at the University
of Surrey for providing me with the support and facilities I require for my work. I also
acknowledge the help from Drs. Paul Hayden and Paul Nathan from the University of Surrey
in upgrading the switching system.
I want to acknowledge the generous sponsorship and support of the Kuwait Institute
for Scientific Research (KISR); without this I would be unable to take the advantage of this
research opportunity. I am grateful to my colleagues in KISR, particularly in the Environment
and Life Sciences Center for their support and valuable advices. I am thankful to the Cultural
Office of the Embassy of the State of Kuwait in London, UK, for their continuous assistance,
advice and evaluation, as well as being a professional contact point. I would also like to
acknowledge the Kuwait National Meteorological Network and Kuwait Environment Public
Authority for providing meteorological and gaseous pollutants data for Fahaheel monitoring
station. I also thank the UK Met Office for providing the meteorological data for Royal
Horticultural Society’s garden in Wisley, Surrey.
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I also wish to thank Professor Min Hu and Dr Jianfei Peng from Peking University for
their enriched suggestions and ideas during the modelling phase of my study, and Dr Jonathan
Symonds and Chris Nickolaus from Cambustion Ltd. for discussion and technical support.
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Statement of Originality
This thesis and the work to which it refers are the results of my own efforts. Any ideas, data,
images or text resulting from the work of others (whether published or unpublished) are fully
identified as such within the work and attributed to their originator in the text, bibliography or
in footnotes. This thesis has not been submitted in whole or in part for any other academic
degree or professional qualification.

Abdullah N. Al-Dabbous
University of Surrey
Monday, 6th of July, 2015
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Publications
A list of research papers, book chapters, conference papers and presentations, reports and our
presence in media during PhD study period, is provided below:
Journal articles
[J1] Al-Dabbous, A.N., Kumar, P., 2014. The influence of roadside vegetation barriers on
airborne nanoparticles and pedestrians exposure under varying wind condition.
Atmospheric Environment 90, 113-124.
[J2] Al-Dabbous, A.N., Kumar, P., 2014. Number and size distribution of airborne
nanoparticles during summertime in Kuwait: first observations from the Middle East.
Environmental Science & Technology 48, 13634-13643.
[J3] Al-Dabbous, A.N., Kumar, P., 2015. Source apportionment of airborne nanoparticles
in a Middle Eastern city using positive matrix factorization. Environmental Science:
Processes & Impacts 17, 802-812.
[J4] Al-Dabbous, A.N., Kumar, P., 2015. Prediction of airborne nanoparticles using a
simple feed-forward artificial neural network: A case study from Kuwait. In
preparation.
Book Chapter
[B1] Kumar, P., Al-dabbous, A.N., 2015. Emission, transformation and fate of nanoparticles
in the atmosphere. In Engineered Nanoparticles and the Environment:
Biophysicochemical Processes and Biotoxicity (IUPAC- Wiley Book Series; Senesi, N.
Eds.). Vol. 4. In Press.

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Conference papers and presentations
[C1] Aldabbous, A., Kumar, P., Robins, A., 2014. Influence of roadside vegetation barriers
on concentrations of traffic-spewed ultrafine particles. HARMO15: 15th International
Conference on Harmonisation within Atmospheric Dispersion Modelling for
Regulatory Purposes, 6–9 May 2013, Madrid, Spain.
[C2] Aldabbous, A., Kumar, P., 2014. Summertime Airborne Nanoparticles: First
Observations from the Middle East. PGRCON2014: 4th Postgraduate Research
Conference at University of Surrey, 3–4 February 2014, Guildford, UK.
[C3] Aldabbous, A., Kumar, P., 2014. Summertime Airborne Nanoparticles: First
Observations from the Middle East. In Air Quality: 9th International Conference on Air
Quality - Science and Application, 24–28 March 2014, Garmisch-Partenkirchen,
Germany.
[C4] Aldabbous, A., Kumar, P., 2014. Summertime airborne nanoparticles in a typical urban
site in Kuwait. KICLS2014: 1st Kuwait International Conference on Life Sciences, 6–
8 April 2014, Kuwait.
Reports
[R1] Aldabbous, A., 2012. Assessment of nanoparticles emissions from road traffic in hot
arid climate. PhD confirmation report. University of Surrey, UK, PP.66.
Media
[M1] Tree-lined roads may help prevent the spread of pollution. University of Surrey, May
2014. Published as a feature story in main page of University of Surrey website.
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[M2] Green corridors protect cyclists and pedestrians from pollution. The Conversation, May
2014.
[M3] City parks are good for people, but not so good for buildings. The Conversation, June
2014.
[M4] City parks are good for people, but not so good for buildings. The Fifth Estate, June
2014.
[M5] First research study on airborne nanoparticles in Middle East. University of Surrey,
November 2014. Published as a feature story in main page of University of Surrey
website.

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Table of Contents
Chapter 1: Introduction .............................................................................................................. 1
1.1 Background and motivation ........................................................................................ 1
1.2 Research aim ............................................................................................................... 6
1.2.1 Assessment of airborne nanoparticles during summertime in Kuwait ................ 6
1.2.2 Source apportionment of airborne nanoparticles in Kuwait ................................ 7
1.2.3 Prediction of airborne nanoparticles using artificial intelligence ........................ 7
1.2.4 Mitigation of airborne nanoparticles by roadside vegetation barrier ................... 8
1.3 Research approach....................................................................................................... 8
1.4 Report outline ............................................................................................................ 10
Chapter 2: Literature review .................................................................................................... 13
2.1 Introduction ............................................................................................................... 13
2.2 Up-to-date summary of published review articles on this topic................................ 14
2.3 Aerosol properties ..................................................................................................... 17
2.4 Nanoparticles and their classifications according to size ranges .............................. 18
2.4.1 Nucleation mode particles.................................................................................. 19
2.4.2 Aitken mode particles ........................................................................................ 20
2.4.3 Accumulation mode particles ............................................................................ 20
2.4.4 Relative contribution of the different size ranges to the total PNCs .................. 21
2.5 Sources of nanoparticles............................................................................................ 21
2.5.1 Natural sources................................................................................................... 22
2.5.2 Anthropogenic sources....................................................................................... 22
2.5.2.1 Road vehicles .............................................................................................. 22
2.5.2.2 Non-vehicle sources ................................................................................... 25
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