Seasonal Changes in the Concentrations of Major Cations and Anions in Precipitations in Urban Nagoya, Japan

Abstract

A continuous sampling at every 0.5mm of precipitation during rain (average sampling time of 19 minutes) and analyses of ions involved in the rainwater were carried out from April 1, 1993 to March 31, 1994 in Nagakute, 16km east of Nagoya, Japan, to understand temporal changes in ion concentrations in precipitation in detail. The average pH, nitrate (N03-), and non-seasalt sulfate (nss-S042) in the collected rainwaters were 4.76, 14.5 peq 1-1 and 18.0 ueq 1-l, respectively. The average concentrations of ions obtained in this study were about half of those obtained during 1984 and 1986 by the Japan Environmental Agency, which was thought to be caused by either the longer rainy season in 1993 or the reduction of sulfur dioxide emission in recent years.The seasonal changes in ion concentrations show that they were significantly influenced by Asian dust storms and typhoons. Asian dust storms and typhoons were found to play important role in characterizing the precipitation chemistry in Japan.A rapid change in ion concentrations during several minutes was frequently found in individual precipitation accompanied by weather change. Concentrations of N03-, NH4+, and SO42-decreased with an increase in wind speed, while those of Na+ and Cl-increased, showing the differences in the production and the deposition processes of ions. Higher concentrations of N03-and nss-SO42-in rain samples with southern wind direction were frequently observed, showing a clear relation to the industrial facilities of ion sources located in the southern direction. A greater amount of ammonium ion (NH4+) was observed to be transported from the suburbs of Nagoya rather than from the downtown area. This measurement (short period sampling and continuous observation) showed characteristics typical of a precipitation chemistry, especially for the seasonal concentration change in major cations and anions and ion transport processes, observed in suburbs in the eastern Asia region.

On the Kosa (Asian Dust) Event in November 2002: Aerosol Number Concentrations and Precipitation Chemistry in Toyama, Japan

“…Kosa particles are rich in CaCO 3 (Tsuruta 1991) and suppress acidification of rain and cloud water (Minoura et al 1998;Watanabe et al 1999 and2001a). High concentrations of Ca 2þ are detected in cloud and rain water that contain Kosa particles (Dokiya et al 1995;Watanabe et al 1999 and2001a).…”

“…Precipitation chemistry affected by Kosa particles has been examined (Dokiya et al 1995;Minoura et al 1998). Kosa or mineral particles also were studied by electron microscopy (Okada et al 1987;Niimura et al 1998).…”

Exacerbation of daily cough and allergic symptoms in adult patients with chronic cough by Asian dust: A hospital-based study in Kanazawa

“…Asian dust is sand from the Taklamakan Desert, the Gobi Desert and the Loess area of interior China that is blown by westerly winds to countries such as Japan, which are positioned downwind. These sand storms typically occur during the spring and sometimes during the late fall in the Northern Hemisphere (Iwasaka et al, 2003;Minoura et al, 1998). Epidemiological studies have shown that Asian dust increases hospitalizations and emergency visits because it exacerbates asthma (Kanatani et al, 2010;Yang et al, 2005), allergic rhinitis (Chang et al, 2006) conjunctivitis (Yang, 2006) and contact dermatitis (Otani et al, 2012), and it decreases the peak expiratory flow values (Park et al, 2005;Watanabe et al, 2011).…”

Reprint of: Effects of Asian dust on daily cough occurrence in patients with chronic cough: A panel study

“…Asian dust, known as kosa in Japanese, originates from the Taklamakan and Gobi deserts and the Loess plateau of interior China. The dust is then blown eastwards by the westerly winds to countries such as Korea, Taiwan and Japan (Iwasaka et al, 2003;Minoura et al, 1998). Epidemiological studies show that kosa decreases peak expiratory flow values in patients with asthma (Park et al, 2005), and increases the number of hospitalizations and emergency visits through exacerbation of asthma (Kanatani et al, 2010;Yang et al, 2005).…”