Increase in dust storm related PM₁₀ concentrations: A time series analysis of 2001-2015

Over the last decades, changes in dust storms characteristics have been observed in different parts of the world. The changing frequency of dust storms in the southeastern Mediterranean has led to growing concern regarding atmospheric PM₁₀ levels. A classic time series additive model was used in order to describe and evaluate the changes in PM₁₀ concentrations during dust storm days in different cities in Israel, which is located at the margins of the global dust belt. The analysis revealed variations in the number of dust events and PM₁₀ concentrations during 2001-2015. A significant increase in PM₁₀ concentrations was identified since 2009 in the arid city of Beer Sheva, southern Israel. Average PM₁₀ concentrations during dust days before 2009 were 406, 312, and 364 μg m^-3 (median 337, 269,302) for Beer Sheva, Rehovot (central Israel) and Modi'in (eastern Israel), respectively. After 2009 the average concentrations in these cities during dust storms were 536, 466, and 428 μg m^-3 (median 382, 335, 338), respectively. Regression analysis revealed associations between PM₁₀ variations and seasonality, wind speed, as well as relative humidity. The trends and periodicity are stronger in the southern part of Israel, where higher PM₁₀ concentrations are found. Since 2009 dust events became more extreme with much higher daily and hourly levels. The findings demonstrate that in the arid area variations of dust storms can be quantified easier through PM₁₀ levels over a relatively short time scale of several years.