Characteristics of the components of suspended particulate mater (SPM) were investigated, as well as their seasonal variations and compositions in the mountainous and urban areas. The mountainous sampling site was Happo Ridge at an altitude of 1850m and the urban site was the city area in Nagano, the both being in the central mountainous region in inland area of Japan. SPM was sampled by filtering air on a quartz fiber filter set in a low volume air sampler, with a flow rate of 20 1 min E-1 and for a period of one month. In the mountainous area, SO42- concentrations were much higher in spring and summer than those in fall and winter. Almost all of SO42- were considered to be produced by the photooxidation of SO2 and transported for a long distance into that area. Ca2+ concentration increased particularly in March and April in which yellow sand from the Asia Continent arrived at those sites. The seasonal variation of elemental carbon (EC) concentration was small, while organic carbon (OC) increased in spring and summer. This suggested that OC in spring and summer was produced by photochemical reaction. In the urban area, SO42- concentration increased in spring and summer. This seasonal variation was similar to that in the mountainous area, but that level was smaller. Ca2+ concentration increased in winter as a result of the road dust raised by cars. SO42- was most abundant in the mountainous area and attained more than 10 % of the SPM. EC, OC and SO42- were abundant in the urban area and all these components, respectively, were more than 10 % of the SPM. The total concentrations of chemical components analyzed attained 43 % and 68% of SPM in the mountainous and urban areas, respectively. Secondary components occupied 41% and 34% of the total components in the mountainous and urban areas, respectively. The contribution of secondary components in the mountainous area is larger than that in the urban area.

An outbreak of water-borne infection caused with Yersinia pseudotuberculosis serovar O3 occured in Anan town, Nagano prefecture during May to June 1988. A total of 21 elementary school pupils. 10 junior high school pupils and 3 high school students were affected. There was no death, nor secondary infection. Positive rate of isolation of Y. pseudotuberculosis from the feces of patients and healthy persons was 41.2% and 9.5%, respectively. In the outbreak, Y. pseudotuberculosis was the only suspected etiological agent isolated from patients. Sera from 25 patients (73.5%) showed elevated agglutinin liters, ranging from 1 : 80 to 1 : 5,120, against the somatic antigen of the isolates. Sixteen strains isolated from patients and healthy persons possessed approximately 42 Md plasmid and the results of calcium dependency, pyrazinamidase activity and autoagglutination were positive. This was the first report on the outbreak of infection due to this organism in Nagano prefecture.

An outbreak of food-poisoning caused by Campylobacter jejuni occured in Omachi city, Nagano prefecture during November and December, 1981. The symptoms common to the 462 patients were abdominal pain (87.2%), diarrhoea (53.9%), fever (42.6%), nausea (28.6%), headache (9.5%) and vomiting (5.6%). Positive rate of isolation of Campylobacter jejuni from the stools of patients in acute stage and convalescent stage was 36.7%, Sera from 6 patients showed elevated agglutinin liters, ranging from 1 : 40 to 1 : 160, against the formalinized antigens of the isolates. Contamination of a lunch served in the school in November 25th was presumed to be the cause of the outbreak. This was the first report on the outbreak of food-poisoning by this microorganism in Nagano prefecture.