The Evaluation of the Impact of a Saharan Event on Particulate Matter Using Compositional Data Analysis

The proposed approach based on compositional data analysis was applied on simultaneousmeasurements of the mineral element concentrations of PM10 and PM2.5 from a typical suburbansite with and without a Saharan event. The suburban site is located in the city of Rome. The selectedmineral elements were Al, Si, Ca, Fe, Ti, Mg, and Sr. The data relating to these elements are reportedin a previous study. The considered elements are mainly related to mineral matter. The proposedapproach allows statistically validating that the mineral element concentrations of PM during dayswith a Saharan event differ from those without a Saharan event in terms of mineral element composition and size distribution. In particular, the results showed that the compositional data analysisapplied to simultaneous measurements of mineral element concentrations of PM10 and PM2.5 is ahelpful technique that can be used to study environmental sites affected by natural sources such asSaharan events. Moreover, the presented technique can be handy in all those conditions where it isimportant to discriminate whether the occurrence of an exceedance or a violation of the daily limitvalue established for PM could also be due to natural sources.