Particulate matter (PM) comprises a mixture of chemical compounds and water particles found in air. The size of suspended particles is directly related to the negative impact on human health and the environment. Children are particularly sensitive to the effects of air pollution because they breathe faster than adults and thus absorb more pollution. In this paper we presented an analysis of the particulate matter pollution in urban areas of the Republic of Croatia, EU. Data on PM10 and PM2.5 concentrations measured in the stationary measuring stations were located in three continental cities – the city of Zagreb (the capital) and cities of Slavonski Brod and Osijek; and two cities at the Adriatic coast – the city of Rijeka and the city of Dubrovnik. The following parameters were analyzed: a daily course of PM2.5 and PM10 concentrations, mean values of daily PM2.5 and PM10 concentrations and average daily PM2.5 and PM10 concentrations, during four seasons in the periods from 2017 to 2019. At most measuring stations, maximum concentrations were recorded during autumn and winter, which can be explained by the intensive use of fossil fuels and traffic. Increases in PM concentrations during the summer months at measuring stations in Rijeka and Dubrovnik may be associated with the intensive arrival of tourists by air during the tourist season, and lower PM concentrations during the winter periods caused by a milder climate consequently resulting in lower fossil fuels consumption and the use of electric energy for heating.