title: Neutral rains at Athens, Greece: a natural safeguard against acidification of rains.
abstract: Samples of all rains in a period from October, 1998 to January, 1999 at Athens, Greece, were collected. The pH values of almost all of these rains clustered in a high range of 7.0-7.5, with no relation between pH and their SO(4)(2-), NO(3)(-) and Cl(-) contents. In addition, a few rains with low contents of chemical components similar to pure water also were observed, giving a pH (approx. 5.5) of rain caused by dissolution of only atmospheric CO(2) in it. These results indicate that the level of air pollution of Athens by human activity has become lower during the last decade, restoring the neutral condition of rain in this area. Furthermore, the Ca contents and Ca/Mg ratios in these rains, as well as their chemical and isotopic behavior, suggest that particles of calcium carbonate taken in as dust act as a neutralizer of rains. The dust must be derived not only from the urban area of Athens but also from its environs or areas distant from it. Such a mechanism causing universally neutral rains throughout the rainy season at Athens must have worked as a natural safeguard against rains acidified naturally and artificially from ancient times up to recent years, keeping the remains of ancient Greece in a good state of preservation during such a long period.
authors.affiliation: Faculty of Engineering and Resource Science, Akita University, 1-1, Tegata Gakuen-cho, Akita 010-8502, Japan. kita@ipc.akita-u.ac.jp
authors.forename: Itsuro
authors.initials: I
authors.lastname: Kita
authors.forename: Takayuki
authors.initials: T
authors.lastname: Sato
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Kase
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Mitropoulos
mesh_terms: D002119:Calcium Carbonate / Q000032:analysis / Q000737:chemistry*; D002947:Cities; D004391:Dust / Q000032:analysis; D004784:Environmental Monitoring / Q000706:statistics & numerical data*; D006115:Greece; D006859:Hydrogen / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D008274:Magnesium / Q000032:analysis; D009566:Nitrates / Q000032:analysis; D011891:Rain; D012621:Seasons; D013431:Sulfates / Q000032:analysis
chemical_list: D004391:Dust; D009566:Nitrates; D013431:Sulfates; D006859:Hydrogen; D002119:Calcium Carbonate; D008274:Magnesium