28 Nov 2022
28 Nov 2022
Status: this preprint is currently under review for the journal ACP.

Source apportionment study on particulate air pollution in two high-altitude Bolivian cities: La Paz and El Alto

Valeria Mardoñez1,2, Marco Pandolfi3, Lucille Joanna S. Borlaza1, Jean-Luc Jaffrezo1, Andrés Alastuey3, Jean-Luc Besombes4, Isabel Moreno R.2, Noemi Perez3, Griša Močnik5,6,7, Patrick Ginot1, Radovan Krejci9, Vladislav Chrastny10, Alfred Wiedensohler11, Paolo Laj1,8, Marcos Andrade2,12, and Gaëlle Uzu1 Valeria Mardoñez et al.
  • 1Institute des Géosciences de l’Environnement, Université Grenoble Alpes, CNRS, IRD, Grenoble INP, Grenoble, France
  • 2Laboratorio de Física de la Atmósfera, Instituto de Investigaciones Físicas, Universidad Mayor de San Andrés, La Paz, Bolivia
  • 3Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Barcelona, 08034, Spain
  • 4Université Savoie Mont Blanc, CNRS, EDYTEM (UMR 5204), Chambéry 73000, France
  • 5Center for Atmospheric Research, University of Nova Gorica, 5270 Ajdovščina, Slovenia
  • 6Haze Instruments d.o.o., 1000 Ljubljana, Slovenia
  • 7Department of Condensed Matter Physics, Jozef Stefan Institute, 1000 Ljubljana, Slovenia
  • 8Institute for Atmospheric and Earth System Research (INAR), University of Helsinki, 00014 Helsinki, Finland
  • 9Department of Environmental Science & Bolin Centre for Climate Research, Stockholm University, 10691 Stockholm, Sweden
  • 10Department of Environmental Geosciences, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, 165 00, Prague-Suchdol, Czech Republic
  • 11Leibniz Institute for Tropospheric Research (TROPOS), 04318 Leipzig, Germany
  • 12Department of Atmospheric and Oceanic Sciences, University of Maryland, College Park, MD, USA

Abstract. La Paz and El Alto are two fast-growing high-altitude Bolivian cities forming the second largest metropolitan area in the country, located between 3200 and 4050 m a.s.l. Together they host a growing population of around 1.8 million people. The air quality in this conurbation is strongly influenced by urbanization. However, there are no comprehensive studies that have assessed the sources of air pollution and their impacts on health. Despite being neighboring cities, the drastic change in altitude and topography between La Paz and El Alto together with different socio-economic activities lead to different sources, dynamics and transport of particulate matter (PM). In this investigation, PM10 samples were collected at two urban background stations located in La Paz and El Alto between April 2016 and June 2017. The samples were later analyzed for a wide range of chemical species including numerous source tracers (OC, EC, water-soluble ions, sugar anhydrides, sugar alcohols, trace metals, and molecular organic species). The US-EPA Positive Matrix Factorization (PMF v.5.0) receptor model was then applied for source apportionment of PM10. This is the first source apportionment study in South America that incorporates a large set of organic markers (such as levoglucosan, polycyclic aromatic hydrocarbons – PAH, hopanes and alkanes) together with inorganic species. The multisite PMF resolved 11 main sources of PM. The largest annual contribution to PM10 came from two major sources: the ensemble of the four vehicular emissions sources (exhaust and non-exhaust), together responsible for 35 % and 25 % of the measured PM in La Paz and El Alto, respectively, and dust contributing 20 % and 32 % to the total. Secondary aerosols contributed 22 % (24 %) in La Paz (El Alto). Agriculture-related smoke from biomass burning originated in the Bolivian lowlands and neighboring countries contributed to 8 % (7 %) of the total PM10 mass annually. This contribution increased to 17 % (13 %) between August–October. Primary biogenic emissions were responsible for 13 % (7 %) of the measured PM10 mass. Finally, it was possible to identify a profile related to open waste burning occurring between the months of May and August. Despite the fact that this source contributed only to 2 % (5 %) of the total PM10 mass, it constitutes the second largest source of PAHs, compounds potentially hazardous to health. Our analysis resulted in the identification of two specific traffic-related sources. In addition, we also identified a lubricant source (not frequently identified) and a non-exhaust emissions source. This study shows that PM10 concentrations in La Paz and El Alto region are mostly impacted by a limited number of local sources. In conclusion, dust, traffic emissions, open waste burning and biomass burning are the main sources to target in order to improve air quality in both cities.

Valeria Mardoñez et al.

Status: open (until 24 Feb 2023)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse

Valeria Mardoñez et al.

Valeria Mardoñez et al.


Total article views: 290 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
200 84 6 290 19 2 4
  • HTML: 200
  • PDF: 84
  • XML: 6
  • Total: 290
  • Supplement: 19
  • BibTeX: 2
  • EndNote: 4
Views and downloads (calculated since 28 Nov 2022)
Cumulative views and downloads (calculated since 28 Nov 2022)

Viewed (geographical distribution)

Total article views: 283 (including HTML, PDF, and XML) Thereof 283 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
Latest update: 01 Feb 2023
Short summary
La Paz and El Alto are two fast-growing high-altitude Bolivian cities forming the second-largest metropolitan area in the country. The sources of particulate matter (PM) in this conurbation were not previously investigated. This study identified 11 main sources of PM, out of which dust and vehicular emissions stand out as the main ones. The influence of regional biomass combustion and local waste combustion was also observed, with the latter being a major source of hazardous compounds.