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| Shiro Hatakeyama | |
| Director | |
| Chemical Reaction Section, Atmospheric Environment Division | |
| National Institute for Environmental Studies | |
| Environmental Agency | |
| 16-2 Onogawa, Tsukuba , Ibaraki 305-0053, Japan | |
| Tel: +81-298-50-2502 Fax: +81-298-50-2579 | |
| E-mail: hatashir@nies.go.jp |
7,444,000 Yen
(FY 1999; 2,522,000 Yen)
Atmospheric and experimental corrosion tests were carried out to estimate the levels of complicated air pollution in East Asia. Qualitative and quantitative atmospheric corrosion has been monitored on bronze, copper, steel, marble, cedar, cypress and urushi (Japanese lacquer) plates, exposed to outdoor and indoor airs in cities located in East Asia. Brochantite and cuprite were formed on the copper at the places where the sulfur dioxide concentration was high, and basic cupric nitrate and cuprite were formed at the places where the nitrogen dioxide concentration was high. Gypsum was observed on the pieces exposed to the indoor air at all the sites. No gypsum was found on the pieces exposed to the outdoor air. Numerous fine spots (0.2-0.3 mm in diameter) were observed on the surfaces of the urushi plates exposed at Chongqing, China and Taejon, Korea, where were foggy cities. The effects of atmospheric and meteorological factors on copper and marble plates were estimated by using regression analysis in several cities in East Asia. Of the atmospheric factors, sulfur dioxide is mostly destructive to the materials especially in China and South Korea. The copper plates may be corroded under the natural conditions such as meteorological factors and sea salt in Japan. The copper may be increasingly damaged with the deposition flux of sulfur and chlorine. The marble may be significantly degraded by gaseous sulfur dioxide, but receive no effects of sulfate ion in the rain. The copper plates were tested artificially by (1) immersing them in nitric acid, hydrochloric acid and sulfuric acid solutions, (2) exposing to air including sulfur dioxide, nitrogen dioxide and ozone, and (3) exposing to artificial acid rain under a programmed cyclic condition. Cuprite and/or tenorite were formed on the plates in the immersion test and the artificial acid rain test. Basic cupric nitrate and cuprite were observed in the gas exposure test of sulfur dioxide, nitrogen dioxide and ozone. Basic cupric nitrate may be formed at the places where the nitrogen dioxide and the ozone concentrations are relatively high. No brochantite was found on the plates in the gas exposure test. The results of regression analysis were very useful to evaluate the levels of complicated air pollution in East Asia.
East Asia, Acid Deposition, Material Damage, Corrosion Test