Effects of SO₂ and soil acidification, alone and in combination, on growth and nutrient status of masson pine seedlings (Pinus massoniana Lamb.) were investigated. Before transplanting the seedlings, the pH of red-yellow soil was adjusted to pH 3.7 or 4.5 by adding a solution of H₂SO₄. The seedlings were transplanted in the treated soil, then were grown for 18 weeks from 6 June to 10 October, 1993 in open-top chambers (OTC) located in an experimental field (Fuchu, Tokyo). During the growth period, the seedlings were exposed to charcoal-filtered air or SO₂ at 50 or 100 ppb (nl/l) in the OTC for 8 h a day (9: 00-17: 00), 5days a week, for 17 weeks from 13 June, 1993.
Yellowish and whitish visible injuries were observed on the needles of the seedlings grown in the soil adjusted to pH 3.7 and exposed to SO₂ at 100 ppb. The exposure to SO₂ or soil acidification reduced the dry weight growth of the seedlings. However, there were no significant interactive effects of SO₂ and soil acidification on the dry weight growth of the seedlings. Although the exposure to SO₂ did not change the nutrient status of the seedlings, the concentration of Al or Mn increased, but that of Ca in the shoot reduced in the seedlings grown in the soil adjusted to pH 3.7.
From the results obtained in the present study, forest declines of masson pine observed in China may be closely related to relatively high concentrations of atmospheric SO₂, such as above 100 ppb in daily average value, and low soil pH below 4.0 induced by wet or dry deposition of acid substances.

View full abstract

Photosynthetic activity of two-year-old seedlings of Japanese cedar (Cryptomeria japonica D. Don) grown in brown forest soil from granite acidified by adding H₂SO₄ solution was investigated. The amount of H⁺ added to the soil was 20 or 30 meq/l soil, and the soil pH (H₂O) was 3.97 or 3.85, respectively. The seedllings were grown in a greenhouse for 12 weeks from 8 June to 31 August, 1993. The control seedlings were grown in the soil (pH 4.12) during the same period.
Eight or 12 weeks after transplanting, net photosynthetic rate of the seedlings grown in the acidified soilsignificantly reduced as compared with the control value. The kinetic analyses of light-response curves and CO₂-response curves of net photosynthetic rate showed that the quantum yield did not change, but the carboxylation efficiency reduced in the seedlings grown in the acidified soil. There was a highly negative correlation between the concentration of Al in the shoot and the carboxylation efficiency of the seedlings. This result suggests that the reduction of the net photosynthetic rate of the seedlings grown in the acidified soil was probably related to the accumulation of Al in the shoot.

View full abstract

Concentration of particulate sulfur analyzed by PIXE technique, most of which can be regarded as sulfate, increased in a summer night at the same time over the wide area of the Kanto plain. Any emission source of the sulfate which may cause the increase in concentration at midnight could not be assigned in the urban area of Kanto district considering the meteorological condition and behavior of other pollutants. Since the effect of long range transport of particulate sulfurs was suggested, Lagrangian dispersion-advection analysis of particles was carried out using global scale weather analytical data. Results show that the concentration observed at the Kanto plain could be increased by the effect of volcanic gas which had been released from Sakurajima volcano befor 3 days or so.

View full abstract

For the purpose to find out the qauantitative methods for estimating odor of flue gas from unvented kerosene space heaters by means of apparatus, I studied the correlation between the odor intensity by the sensory scale and the concentration of odor substances. The confirmations of volatile substances in flue gas were carried out for unvented kerosene space heaters with 3 different combustion systems by GC/MS and GC/FT-IR, and 88 volatile compounds were confirmed. 30 compounds from these 88 compounds were selected as ofor substances.
By GC/MS (Selected ion monitoring method), the concentrations of these 30 compounds were measured in regard to 10 unvented kerosen space heaters with 3 different combustion systems at 3 states (ignition, combustion, and extinguishment). At the same time, the odor intensity was by the sensory scale in regard to 10 unvented kerosen space heaters at 3 states.
The results are as follows:
(1) The high correlation was found between the odor intensity and the concentrations of Acrolein, Toluene, 1-Pentene and Crotonaldehyde at the state of ignition.
(2) The high correlation was found between the odor intensity and the concentrations of Methyl Cyclohexane, Allylacetone, iso-Propyl Methyl Ketone and Propionaldehyde at the state of extiguishment, but was not found at the state of combustion because its odor intensity was weak.
At the states of ignition and extinguishment, the model formulae predcting the odor intensity from the concentrations of odor substances was studied concerning the concentrations of odor substances highly correlating with the odor intensity by the multiple regression analysis.

View full abstract

Air quality in Shenyang (China) was investigated by several approaches. The ambient concentrations of NO₂ and SO₂ were measured in residential area (hotel) with passive sampler from llth Oct. through 15th Oct. Fluctuations of the results ranges for NO₂ and SO₂ were 26-39 ppb respectively. Triethanolamine (TEA: SO₂-sensitive reagent) could probably collected SO₂ well enough at extraordinary low temperature (-20°C), even though the collection efficiency was not 100%. Another possible simple and effective indicator was contents of water soluble ions (SO₄^2-, Cl^- and Ca²⁺) on the surface of the broadleaf-tree leaves in the school gardens in the area of different pollution intensity (heavy/intermediate/non-polluted) selected as the target sites of epidemiological risk study. Heavy metals contained in the same leaves were also useful for the above purpose. Falling dust attaching on the surface of leaves and in the ambient air at a hotel were analyzed with a scanning electron microscope (SEM) and an electron probe micro-analyzer (EPMA), and it was found the those consist mainly of soil-particles. But fly-ash was also identified in a few case.

View full abstract