Assessment and application of clustering techniques to atmospheric particle number size distribution for the purpose of source apportionment
Farhad Salimi,Zoran Ristovski,Mandana Mazaheri,Rusdin Laiman,Leigh R. Crilley,Leigh R. Crilley,Congrong He,Samuel Clifford,Lidia Morawska +8 more
TLDR
Clustering was found to be an effective technique for attributing each particle size spectrum to its source and the GAM was suitable to parameterise the PNSD data.Abstract:
. Long-term measurements of particle number size distribution (PNSD) produce a very large number of observations and their analysis requires an efficient approach in order to produce results in the least possible time and with maximum accuracy. Clustering techniques are a family of sophisticated methods that have been recently employed to analyse PNSD data; however, very little information is available comparing the performance of different clustering techniques on PNSD data. This study aims to apply several clustering techniques (i.e. K means, PAM, CLARA and SOM) to PNSD data, in order to identify and apply the optimum technique to PNSD data measured at 25 sites across Brisbane, Australia. A new method, based on the Generalised Additive Model (GAM) with a basis of penalised B-splines, was proposed to parameterise the PNSD data and the temporal weight of each cluster was also estimated using the GAM. In addition, each cluster was associated with its possible source based on the results of this parameterisation, together with the characteristics of each cluster. The performances of four clustering techniques were compared using the Dunn index and Silhouette width validation values and the K means technique was found to have the highest performance, with five clusters being the optimum. Therefore, five clusters were found within the data using the K means technique. The diurnal occurrence of each cluster was used together with other air quality parameters, temporal trends and the physical properties of each cluster, in order to attribute each cluster to its source and origin. The five clusters were attributed to three major sources and origins, including regional background particles, photochemically induced nucleated particles and vehicle generated particles. Overall, clustering was found to be an effective technique for attributing each particle size spectrum to its source and the GAM was suitable to parameterise the PNSD data. These two techniques can help researchers immensely in analysing PNSD data for characterisation and source apportionment purposes.read more
Citations
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Traffic and nucleation events as main sources of ultrafine particles in high-insolation developed world cities
M. Brines,M. Brines,Manuel Dall'Osto,Manuel Dall'Osto,David C. S. Beddows,Roy M. Harrison,Roy M. Harrison,Francisco J. Gómez-Moreno,L. Núñez,Begoña Artíñano,Francesca Costabile,Gian Paolo Gobbi,Farhad Salimi,Lidia Morawska,Constantinos Sioutas,Xavier Querol +15 more
TL;DR: In this paper, three cities located in predominantly sunny environments: Barcelona (Spain), Madrid (Spain) and Brisbane (Australia) were systematically studied three long-term data sets (1-2 years) of fine and ultrafine particle number size distributions (measured by SMPS, Scanning Mobility Particle Sizer) were analyzed.
Journal ArticleDOI
Children's well-being at schools: Impact of climatic conditions and air pollution.
Tunga Salthammer,Erik Uhde,Tobias Schripp,Alexandra Schieweck,Lidia Morawska,Mandana Mazaheri,Samuel Clifford,Congrong He,Giorgio Buonanno,Xavier Querol,Mar Viana,Prashant Kumar +11 more
TL;DR: This review summarizes the current results and knowledge gained from the scientific literature on air quality in classrooms and possible scenarios for the future are discussed and guideline values proposed which can serve to help authorities, government organizations and commissions improve the situation on a global level.
Journal ArticleDOI
Effects of exposure to ambient ultrafine particles on respiratory health and systemic inflammation in children
Samuel Clifford,Mandana Mazaheri,Farhad Salimi,Wafaa Nabil Ezz,Bijan Yeganeh,Samantha Low-Choy,Katy Walker,Kerrie Mengersen,Guy B. Marks,Guy B. Marks,Lidia Morawska +10 more
TL;DR: UFPs do not affect respiratory health outcomes in children but do have systemic effects, detected here in the form of a positive association with a biomarker for systemic inflammation, consistent with the known propensity of UFPs to penetrate deep into the lung and circulatory system.
Journal ArticleDOI
Sources of sub-micrometre particles near a major international airport
TL;DR: In this article, two sampling campaigns were carried out during warm and cold seasons at a site close to the airfield (1.2 km). Size spectra were largely dominated by ultrafine particles: nucleation particles.
Journal ArticleDOI
Variability in exposure to ambient ultrafine particles in urban schools: Comparative assessment between Australia and Spain
Mandana Mazaheri,Cristina Reche,Ioar Rivas,Leigh R. Crilley,Mar Alvarez-Pedrerol,Mar Viana,Aurelio Tobias,Andrés Alastuey,Jordi Sunyer,Xavier Querol,Lidia Morawska +10 more
TL;DR: In this paper, the authors quantitatively compare exposure to ambient ultrafine particles at urban schools in two cities in developed countries, namely Brisbane (Australia) and Barcelona (Spain), using comprehensive indoor and outdoor air quality measurements at 25 schools in Brisbane and 39 schools in Barcelona.
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