title: Variability in exposure to ambient ultrafine particles in urban schools: Comparative assessment between Australia and Spain.
abstract: Ambient ultrafine particle number concentrations (PNC) have inhomogeneous spatio-temporal distributions and depend on a number of different urban factors, including background conditions and distant sources. This paper quantitatively compares exposure to ambient ultrafine particles at urban schools in two cities in developed countries, with high insolation climatic conditions, namely Brisbane (Australia) and Barcelona (Spain). The analysis used comprehensive indoor and outdoor air quality measurements at 25 schools in Brisbane and 39 schools in Barcelona. PNC modes were analysed with respect to ambient temperature, land use and urban characteristics, combined with the measured elemental carbon concentrations, NOx (Brisbane) and NO2 (Barcelona). The trends and modes of the quantified weekday average daily cycles of ambient PNC exhibited significant differences between the two cities. PNC increases were observed during traffic rush hours in both cases. However, the mid-day peak was dominant in Brisbane schools and had the highest contribution to total PNC for both indoors and outdoors. In Barcelona, the contribution from traffic was highest for ambient PNC, while the mid-day peak had a slightly higher contribution for indoor concentrations. Analysis of the relationships between PNC and land use characteristics in Barcelona schools showed a moderate correlation with the percentage of road network area and an anti-correlation with the percentage of green area. No statistically significant correlations were found for Brisbane. Overall, despite many similarities between the two cities, school-based exposure patterns were different. The main source of ambient PNC at schools was shown to be traffic in Barcelona and mid-day new particle formation in Brisbane. The mid-day PNC peak in Brisbane could have been driven by the combined effect of background and meteorological conditions, as well as other local/distant sources. The results have implications for urban development, especially in terms of air quality mitigation and management at schools.
authors.affiliation: International Laboratory for Air Quality and Health, Queensland University of Technology, Brisbane, Australia; Institute for Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia.
authors.forename: Mandana
authors.initials: M
authors.lastname: Mazaheri
authors.affiliation: Institute of Environmental Assessment and Water Research, Spanish National Research Council Barcelona, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Reche
authors.affiliation: Institute of Environmental Assessment and Water Research, Spanish National Research Council Barcelona, Spain; Centre for Research in Environmental Epidemiology, Barcelona, Spain.
authors.forename: Ioar
authors.initials: I
authors.lastname: Rivas
authors.affiliation: School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: Leigh R
authors.initials: LR
authors.lastname: Crilley
authors.affiliation: Centre for Research in Environmental Epidemiology, Barcelona, Spain.
authors.forename: Mar
authors.initials: M
authors.lastname: Álvarez-Pedrerol
authors.affiliation: Institute of Environmental Assessment and Water Research, Spanish National Research Council Barcelona, Spain.
authors.forename: Mar
authors.initials: M
authors.lastname: Viana
authors.affiliation: Institute of Environmental Assessment and Water Research, Spanish National Research Council Barcelona, Spain.
authors.forename: Aurelio
authors.initials: A
authors.lastname: Tobias
authors.affiliation: Institute of Environmental Assessment and Water Research, Spanish National Research Council Barcelona, Spain.
authors.forename: Andrés
authors.initials: A
authors.lastname: Alastuey
authors.affiliation: Centre for Research in Environmental Epidemiology, Barcelona, Spain.
authors.forename: Jordi
authors.initials: J
authors.lastname: Sunyer
authors.affiliation: Institute of Environmental Assessment and Water Research, Spanish National Research Council Barcelona, Spain.
authors.forename: Xavier
authors.initials: X
authors.lastname: Querol
authors.affiliation: International Laboratory for Air Quality and Health, Queensland University of Technology, Brisbane, Australia; Institute for Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia. Electronic address: l.morawska@qut.edu.au.
authors.forename: Lidia
authors.initials: L
authors.lastname: Morawska
mesh_terms: D000293:Adolescent; D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000032:analysis*; D001315:Australia; D002648:Child; D002675:Child, Preschool; D002947:Cities; D004781:Environmental Exposure / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis*; D012574:Schools; D013030:Spain; D014505:Urban Population / Q000706:statistics & numerical data
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter
keywords: Ambient particles; Exposure; High insolation areas; New particle formation; Urban environments