Temporal evolution of main ambient PM2.5 sources in Santiago, Chile, from 1998 to 2012
Francisco Barraza1,4, Fabrice Lambert1,4, Héctor Jorquera2,5, Ana María Villalobos2, and Laura Gallardo3,41Geography Institute, Pontificia Universidad Católica de Chile, Santiago, 7820436, Chile 2Department of chemical engineering and bioprocesses, Pontificia Universidad Católica de Chile, Santiago, 7820436, Chile 3Department of Geophysics, Universidad de Chile, Santiago, Chile 4Center for Climate and Resilience Research, University of Chile, Santiago, Chile 5Center for Sustainable Urban Development (CEDUS), Pontificia Universidad Católica de Chile, Santiago, 7820436, Chile
Received: 06 Jan 2017 – Accepted for review: 14 Jan 2017 – Discussion started: 18 Jan 2017
Abstract. The inhabitants of Santiago in Chile have been exposed to harmful levels of air pollutants for decades. The city's poor air quality is a result of sustained emissions and stable atmospheric conditions, averse to mixing and ventilation and favorable for the formation of oxidants and secondary aerosols. Identifying and quantifying the sources that contribute to the ambient levels of pollutants is key for designing adequate mitigation measures. Knowledge about the temporal evolution of the contribution of each source to ambient pollution levels is also paramount to evaluate the effectiveness of pollution reduction measures that have been implemented in the past decades. Here, we quantify the main sources that have contributed to fine particulate matter (PM2.5) between 1998 and 2012 in Santiago's center by using two different source-receptor models (PMF 5.0 and Unmix 6.0), that re applied to elemental measurements on 1243 24-hour filter samples of ambient PM2.5 collected between April-1998 to August-2012. Both models resolve six sources that contribute to ambient PM2.5: motor vehicles (37 %), industrial sources (19 %), copper smelters (14 %), wood burning (12 %), coastal sources (10 %), and urban dust (3 %). Our results show that over the 15 years analyzed here, the emissions from motor vehicles, industrial sources, copper smelters, and coastal sources declined by about 21, 39, 81, 59, and 59 % respectively, while wood burning didn’t change and urban dust increase by 72 %. These changes are consistent with emission reduction measures, such as improved vehicle and smelting technology, introduction of low sulfur fuel for vehicles and natural gas for industrial processes, emission controls for vehicles, public transport improvements etc. However, it is also apparent that the mitigation expected from improved public transport, vehicle technology, and fuel has been largely nullified by the ever-rising number of private vehicle journeys in the past decade. As a consequence, Santiago still experiences PM2.5 levels above the annual and 24-hours Chilean and World Health Organization standards.
Barraza, F., Lambert, F., Jorquera, H., Villalobos, A. M., and Gallardo, L.: Temporal evolution of main ambient PM2.5 sources in Santiago, Chile, from 1998 to 2012, Atmos. Chem. Phys. Discuss., doi:10.5194/acp-2017-18, in review, 2017.