『Abstract
A field survey on the concentration of chemical species in
particulate matter and gaseous compounds at two monitoring sites
with different site classifications (urban and rural) was conducted
over three years. Total (particulate matter + gaseous compounds)
concentrations at the rural site were significantly lower than
those at the urban site for all species (sulfur (SO42-(p)
and SO2(g)), nitrate (NO3-(p)
and HNO3(g)), ammonium (NH4+(p))
and ammonia (NH3(g)), and chloride (Cl-(p)
and HCl(g)), which is thought to reflect classification of the
site. The difference in the sulfur concentration at the urban
and rural sites was characterized by the difference in SO2 (g) concentration. Further, a clear seasonality
was observed for the nitrate species. The HNO3
(g) concentration was high in the summer compared with other seasons
at both the urban and rural sites. The NH4+
(p) concentration levels were approximately the same as those
of NH3 (g) at both sites. The molar ratios
of the particulate matter concentration to the total concentration
showed different characteristics; the nitrate, ammonium and ammonia,
and chloride species showed a clear seasonal variation: low in
summer and high in winter and the values were similar regardless
of the site. On the other hand, the sulfur species showed constant
values at both the urban and rural sites, however the concentrations
were significantly different for the two sites. Ammonium accounted
for the largest proportion of cations in the particulate matter,
regardless of the site classification. In contrast, SO42-
(p) accounted for the largest proportion of anions at the rural
site, whereas NO3- (p) was comparable
to SO42- (p) at the urban site.
Ammonia accounted for the largest proportion of all chemical species
at both sites. Seasonal analysis of the proportional distribution
in particulate matter and gaseous compounds provides information
on atmospheric conditions.
Keywords: Ammonia; Ammonium; Filter pack; Nitrate; Nitric acid
gas; Site classification; Sulfate; Sulfur dioxide』
1 Introduction
2 Experimental
2.1 Monitoring site
2.2 Sample collection and analysis
2.2.1 Method and period
2.2.2 Chemical and statistical analyses
3 Results and discussion
3.1 Data assessment
3.2 Concentrations of chemical species
3.2.1 Sulfur species
3.2.2 Nitrate species
3.2.3 Ammonium and ammonia
3.2.4 Chloride species
3.3 Distribution of particulate matter and gaseous compounds
3.3.1 Sulfur species
3.3.2 Nitrate species
3.3.3 Ammonium and ammonia
3.3.4 Chloride species
3.4 Proportional distribution in particulate matter and gaseous
compounds
3.5 Comparison of this survey with JELA survey
4 Conclusions
Acknowledgements
References