Major air pollutants such as diesel exhaust, ozone (O₃) and nitrogen dioxide (NO₀) aggravate nasal allergic reactions such as sneezes and nasal secretion and allergic conjunctivitis such as eye congestion, induced by repeated antigen administration in guinea pigs. The results suggest that hyperresponsiveness, increases in titers of specific antibody and infiltration of eosinophils are factors responsible for the augmentation of allergic reactions.

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The Community Multi-scale Air Quality (CMAQ) modeling system coupled with the Regional Atmospheric Modeling System (RAMS) and year-by-year emission inventory in Asia (REAS ver. 1.1) was applied to East Asia to analyze inter-annual variation and their factor for nss-SO₄ ²-deposition from 1995 to 2003. The average value of 18 monitoring stations excluding Ogasawara which leaves from the Japan main island that measured throughout the period 1995 to 2003 increase from 1999. CMAQ can reproduce the feature of measured trend and time variation. Then, the model was applied to examine three factors responsible for the variation of Japanese nss-SO₄^2- deposition, meteorology, SO₂ emission from Miyakejima, and SO₂ emission from the other sources. The inter-annual meteorological variation in East Asia influences Japanese nss-SO₄ ^2- deposition, and is a major cause of the interannual variation of Japanese nss-SO₄^2- deposition. Miyakejima volcano has a large impact on the variation of Japanese nss-SO₄^2- deposition in 2001, but that impact is small after 2002. The trend of Japanese nss-SO₄^2- deposition caused by SO₂ emission from other than Miyakejima has been increased after 2000, which correlated well with Chinese SO₂ emission. It is suggested that Chinese SO₂ emission largely affects Japanese nss-SO₄^2- deposition, In west Japan, meteorological variation and trend of SO₂ emission in East Asia have a large influence on inter-annual variation of nss-SO₄ ^2- deposition and the trend of nss-SO₄ ^2- deposition, respectively, because Miyakejima emission has little impacts on nss-SO₄^2- deposition, and Chinese emission has also a large effect on the trend of nss-SO₄^2- deposition than contribution to Japan.

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We conducted the measurements of the concentrations of particulate matter (PM; PM_2.5, PM_10-2.5 and PM₁₀) at a district in Tokyo late 1980s. The environmental measurements were conducted four times indoors in 200 households and two times both indoors and outdoors in 100 households. We obtained the following results.
PM concentrations were higher in winter than in summer. Outdoor PM_2.5 and PM₁₀ concentrations were higher in roadside area than backyard but not for PM_10-2.5. PM_2.5 concentrations in the smokers' houses were significantly higher than those in the non-smokers' houses. PM_2.5 concentrations increased according to the number of cigarettes smoked and its magnitude was large in winter because of the small air-exchange. PM_2.5 concentrations in houses using un-ventilated stoves were significantly higher than thosein houses using ventilated stoves. PM_10-2.5 concentrations showed the same results but the significant difference was found only in February 1987 where ambient temperature was the lowest. I/O ratios (indoor concentration/ outdoor concentration) were lower in winter than in summer for PM_2.5, PM_10-2.5 and PM₁₀ except for PM_2.5 and PM₁₀ in smokers' houses. Indoor PM_10-2.5 concentrations were significantly lower than outdoors. The correlation coefficients between the indoor and outdoor concentrations were large in summer for all PM. The outdoor PM_2.5/ PM₁₀ratios were larger in winter than in summer and were smaller than those indoors. Indoor PM_2.5/ PM₁₀ ratios ranged 60 to 80% and showed a tendency to be larger in winter.
In this study we clarified the indoor and outdoor concentration levels of PM_2.5, PM_10-2.5 and PM₁₀ in different seasons in Tokyo late 1980s and we discussed some factors which regulate the indoor-outdoor relationships of PM. Further we determined the relationship between PM2.5 and PM₁₀.

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The highly time-resolved observation of non-refractory fine particle composition was analyzed at a subuiban site at Saitama, Japan, in the winter of December 2004-January 2005, using an Aerodyne aerosol mass spectrometer. The result showed that organics and nitrate were the dominant species during the sampling period except for the large fraction of sulfate during high wind speed periods. Positive matrix factorization (PMF) was used to identify the main organic components and their sources for the organic aerosol mass spectra and five factors were identified. The five factors could be assigned either to combustion sources (Hydrocarbon-like Organic Aerosol, HOA and Biomass Burning Organic Aerosol, BBOA) or to aerosol components such as oxygenated organic aerosol (OOA type 1, 00A type 2, and oxy-HOA). This is the first case study of a PMF analysis result to AMS organic spectral data in Japan and also the first report of the oxy-HOA component (factor). This oxygenated organic aerosol (OOA) can be separated into OOA type 1 (21 % as contribution to total organics) with small m/z and a mass spectrum similar to secondary organic aerosols in smog chamber experiment, a highly aged fraction, OOA type 2, (21 %), oxygenated signal of m/z 44 (mostly CO₂⁺) with HOA, oxy-HOA (18 %), and levoglucosan, BBOA (25 %). The results of analysis in this investigation indicated that OOA originated from secondary and aging source was higher contribution than other three factors at the measurement site and only a small contribution (16 % as HOA) of fine organic particles originated from freshly mobile emissions. The contribution of BBOA (25 %) was similar with our previous data of Ca. 31 % of total carbon calculated from levoglucosan concentration. These fractions indicated that the source contributions to organics were associated with meteorological parameter based on wind speed and particle concentration.

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Trends in concentration of photochemical oxidant has recently been increased. Oxidant concentration sometimes exceed the photochemical smog advisory level (120ppb (v/v)) in Fukuoka prefecture.
Then, the oxidant high concentration days (from 2003 to 2007) are extracted to estimate sources. It is said that high oxidant concentration are caused by generation in local area, the transportation from the continent and tropospheric intrusion of the stratospheric ozone. If we can get data such as backward trajectory, sulfate concentration at Fukuoka and oxidant data in Tsushima or Iki island where is the background measurement site located between Kyushu and the continent, we are able to specify the main factor in some cases on a high concentration days though influence of each factor combines. When the strong influence was classified, it was estimated at over 30% transportation from the continent. The ratio of transportation from the continent is slightly increasing.

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Immature individuals under development are considered to have high sensitivity and vulnerability to chemicals. It therefore pays attention to the risk assessment for environmental chemical exposure in fetuses, infants and children. We here focused on the developmental neurotoxicities of VOCs and pesticides and reviewed articles in the studies reporting the effects of developmental exposure to these chemicals on the central nervous system. Our reviews could be contributed to the hazard assessment of VOCs and pesticides in fetuses, infants and children.

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