The continuous highly resolved records of Cl-, Na+, and Ca2+ in ice cores from Col du D¿me (4250 m elevation, French Alps) and Summit (3240 m elevation, central Greenland) are used to reconstruct the history of atmospheric HCl pollution over Europe and Greenland since the early 20th century. The evaluation of the HCl amount in summer snow deposits at high-elevation Alpine sites is complex since continental emissions (soils, halide evaporites, and possibly manure-fertilized fields) account for 80% of the chloride budget and only one fifth of Cl- is related to HCl. During the preindustrial era the HCl content of summer Alpine snow layers fluctuated between 0 and 6 ng g-1, likely in relation with a highly variable interannual biomass burning activity in western Europe. From 1925 to 1960 the HCl levels were slightly higher (3--9 ng g-1), mainly due to growing coal burning emissions in western Europe. In the late 1960s a sharp increase of HCl levels (up to 17 ng g-1) took place as a result of the setup of waste incineration in western Europe, this process contributing 3--4 times more than coal combustion to the HCl budget of summer Alpine snow layers deposited between 1970 and 1990. In winter, sea spray emissions dominate (~78%) the total Cl- level of Alpine snow layers. The HCl trend in these snow layers remained limited to ~2 ng g-1 over the 20th century, likely in relation to waste incineration after 1965. In Greenland snow layers most of particulate Cl- originates from sea spray, 1/3 to 2/3 of Cl- being present as HCl in spring and summer, respectively. The Greenland HCl ice core records indicate a preindustrial HCl level close to 4 ng g-1, which is found to be mainly due to the sea-salt dechlorination, while the contribution of passive volcanic HCl emissions at high northern latitudes can be neglected. The input from sea-salt dechlorination has been enhanced by a factor of 2--3 during the second half of the 20th century similarly to the increase of the atmospheric acidity in response to growing NOx and SO2 anthropogenic emissions.