Interrelationships between major components of PM10 and sub-micron particles: Influence of Atlantic air masses

Abstract

In this study, a characterization of particulate matter (PM10) is performed in a suburban area in Northwestern Spain (A Coruña, Galicia), in order to establish the interrelationships between major components, as well as between these components and submicron particles. 140 PM10 samples were collected from April 2014 to January 2015 and numerous chemical parameters, such as carbonaceous fraction, including water-soluble organic carbon (WSOC), major ions, and carbon and nitrogen isotopic ratios, were determined. Data on ultrafine particles for one season were also recorded. Nanoparticle modes showed a correlation between them and with all of the carbonaceous fractions (especially elemental carbon and Aitken mode) and some meteorological parameters (humidity and solar radiation). Their correlations suggested the possible influence of a few industrial sources, depending on the prevailing winds. Isotopic data indicated the presence of a significant input from combustion sources during the cold period and primary biogenic input during the spring, reinforced by OC/EC ratios and WSOC values. Organic carbon (OC), the main component of carbonaceous fraction, correlates seasonally with elemental carbon (EC), setting a fitting to a potential equation during the winter. These parameters also suggested a significant presence of secondary organic aerosol in the area, except in the spring. A high contribution of secondary inorganic aerosol was also observed, with ammonium sulfate (all of the seasons), sodium nitrate with a marine contribution (except in the autumn), and potassium sulfate (except in the spring) as the main species. The Atlantic Ocean's influence was observed as a contribution of sea salt to PM10 of 23.4% on average, up to 84.5% on certain days, and a strong relationship between sea salt and secondary aerosol.