AIP Conference Proceedings [AIP Publishing APPLICATION OF MATHEMATICS IN TECHNICAL AND NATURAL SCIENCES: 11th International Conference for Promoting the Application of Mathematics in Technical and Natural Sciences - AMiTaNS’19 - Albena, Bulgaria (20–25 June 2019)] APPLICATION OF MATHEMATICS IN TECHNICAL AND NATURAL SCIENCES: 11th International Conference for Promoting the Application of Mathematics in Technical and Natural Sciences - AMiTaNS’19 - Statistical study of the influence of the atmospheric characteristics upon the particulate matter (PM10) air pollutant in the city of Silistra, Bulgaria