Model-simulated source contributions to PM2.5 in Santiago and the central region of Chile
Artikel i vetenskaplig tidskrift, 2020

The contributions to PM2.5 from different emission sectors across central Chile and the Santiago metropolitan area during summer/fall and winter have been evaluated using a chemical transport model. The simulations generally underestimate the mean PM2.5 concentrations compared to measurements conducted at stations in Santiago that belong to the Chilean National Air Quality Information System (SINCA). The potential reasons for this discrepancy include underestimated direct PM2.5 emissions, missing emissions for semi-and intermediately volatile organic compounds (SVOCs and IVOCs) and overestimated wind speeds in the simulations. The simulated winter PM2.5 concentrations in Santiago are lower and higher than the values observed during nighttime, and daytime and late evening, respectively, which may be related to excessive simulated wind speeds, as well as to uncertainties in the diurnal variation in the emissions. During summer/fall, the simulated diurnal variation better agrees with the observations, but the peak concentrations during the morning are underestimated, whereas those during the evening are overestimated. The simulated contributions of different aerosol components to the PM2.5 at one station in Santiago are all lower than the observed values, except for elemental carbon equivalent black carbon (BCe), which exhibit comparable or higher levels in the simulations. The absolute differences are the largest for the total organic matter, whereas the relative differences are the largest for BCe and ammonium. The simulated sector contributions indicate that emissions originating from transport and construction machinery dominate the PM2.5 in Santiago; however, residential wood combustion is the primary source in other urban areas of central Chile, except near major point sources. Away from urban areas, traffic routes and major industrial sources, secondary inorganic aerosol (SIA) is estimated to be the largest component of the aerosol, whereas the simulated secondary organic aerosol (SOA) only contributes a small fraction.

Chemical composition

Urban

Secondary aerosol formation modeling

Författare

J. Langner

SMHI

Lars Gidhagen

SMHI

Robert Bergström

Chalmers, Rymd-, geo- och miljövetenskap, Mikrovågs- och optisk fjärranalys

SMHI

Ernesto Gramsch

Universidad de Santiago de Chile

Pedro Oyola

Centro Mario Molina, Chile

Felipe Reyes

Centro Mario Molina, Chile

David Segersson

SMHI

Claudio Aguilera

Centro Mario Molina, Chile

Aerosol and Air Quality Research

1680-8584 (ISSN)

Vol. 20 5 1111-1126

Ämneskategorier

Meteorologi och atmosfärforskning

Naturgeografi

Miljövetenskap

DOI

10.4209/aaqr.2019.08.0374

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Senast uppdaterat

2020-06-03