Research of dustiness on gravelled roads in Lithuania

In Lithuania, the length of gravelled roads amounts to 8,000 km, which accounts for 39% of Lithuania's national roads. Every year this length decreases because more and more gravelled roads are asphalted. The main problem why the society and users are against gravelled roads is their dusting during the warm period of the year. The generation of dust is mainly influenced by the factors of traffic, climate and the quality of gravel applied. Different methods of gravelled road paving treatment are applied to deal with the issues of dustiness. In Lithuania, the most popular and frequent means used to reduce dustiness are petroleum emulsion and calcium chloride. The article presents research findings obtained when analysing gravelled road sections that were treated and not treated with dustiness reducing agents in different regions of Lithuania. The research findings show that the dusting is most efficiently reduced by introducing petroleum emulsion into the paving of gravelled roads. The concentration of suspended particulate matter was measured with the optical dust monitor MicroDust pro. The concentration of suspended particulate matter (mg/m(3)) in environment of gravelled roads was for the most part influenced by climatic conditions - wind speed and relative humidity of the ambient air.