Statistical analysis of ambient air PM10 contamination during winter periods for Ruse region, Bulgaria

The sources of dust on the territory of Ruse region, Bulgaria are industry, transport and domestic heating by solid fuel. PM10 (particulate matter with a diameter between 2.5 and 10 gm) levels for Ruse mark a significant increase during the autumn-winter period compared to the levels during the spring-summer period [1]. Obviously there is a relationship between PM10 contamination levels and ambient air temperature. The lower the temperatures are, the higher the PM10 levels are. The biggest peak of PM10 levels for the autumn-winter period is usually observed in January months. It is in January that the number of days in which there is exceedance of the limit values of the PM10 levels is maximum observed. Also in January months the day and night temperatures are the lowest and usually they do not pass 0 degrees C for many days of the month. To understand better this relationship we provide a statistical analysis of ambient air PM10 contamination during winter periods. Correlations between the measured PM10 values and the respective temperatures measured for January months for different years are presented. Descriptive statistics of PM10 and some atmospheric characteristics as well as linear regression analysis are calculated and commented in the paper.