National and regional trends in ambient ozone measurements, 1975–1981

Long-term (1975–1981) and short-term (1980–1981) national and regional trends in ozone (O₃) are examined. The data used in this paper come from the U.S. Environmental Protection Agency's National Aerometric Data Bank (NADB). Air quality trends are presented for both the National Air Monitoring Sites (NAMS) and all other sites meeting the historical and data completeness criteria. Nationally, the composite average of the second-highest daily maximum 1-h O₃ values recorded at 209 sites decreased 14% between 1975 and 1981. An even greater improvement was observed in the estimated number of exceedances in the ozone season (July–September), which decreased 42%. Volatile organic compound (VOC) emissions decreased 9% during the same time period. The greater improvement observed in ozone levels appears to be a combination of reductions in VOC emissions and the change in the calibration procedure which took place between 1978 and 1979. Between 1980 and 1981, the majority of the 159 monitoring sites with data in both years decreased with a median rate of improvement of 8%. This is consistent with the 7% drop in VOC emissions during this period.     

Urbanization,land use,and water quality in Shanghai. 1947-1996

The paper undertakes a preliminary investigation into the relationship between water quality and urbanization as well as the changing patterns of land use within Shanghai. Longitudinal changes to water quality at various points along the course of the Huangpu River are analysed and compared to changes in the rates of urbanization and changes in land uses. The results reveal that rapid urbanization corresponds with rapid degradation of water quality. It also shows that urban land uses are positively correlated with the decline in water quality. A regression model shows that close to 94% of the variability in water quality classifications is explained by industrial land area. The paper concludes with the need for comprehensive land use planning as a way of protecting valuable water resources.     

Occurrence and distribution of organochlorine pesticides - lindane, p,p'-DDT, and heptachlor epoxide - in surface water of China

Persistent organochlorine pesticides pollutants (OCPs) have been reported to occur at relatively high concentrations in some Chinese waters. In order to map the distribution of organochlorine pesticides in the surface water throughout China, samples were collected from over 600 sites in seven major river basins and three main internal rivers drainage areas during 2003 and 2004. The surface water samples were analyzed for the representative organochlorine pesticides contaminants including lindane (gamma-HCH), p,p'-DDT and heptachlor epoxide. In general, the most frequently detected compound was lindane, being detected in 83.9% of samples (mean=31.3 ng/l; range <0.17-860 ng/l), and the highest concentration was present in the Yellow River basin. p,p'-DDT was detected in 63.1% of the samples collected (mean=14.6 ng/l; range <0.14-368 ng/l) with the highest concentration present in the Huaihe River basin. Heptachlor epoxide was detected in only 9.3% of water samples (range <0.11-10 ng/l). Measured concentrations for the three compounds were low and rarely exceed the environment quality standard for surface water of China. Lindane was more frequently detected at much higher concentrations in the rivers of northern China compared with those of southern China. The sites with higher concentration of lindane and p,p'-DDT mainly occurred in the Yellow River and Huaihe River basins, so the results of this investigation indicate that the organochlorine pesticide contamination of Yellow River and Huaihe River basins should be of particular concern relative to the other basins. When compared with other regions of the world, it appears that the Chinese surface water is moderately polluted by lindane and p,p'-DDT.     

Exposure to radon in Swedish dwellings — Attitudes and elimination

Owners of 208 dwellings with radon daughter concentrations of 400 Bq/m³ EER or above were asked about attitudes and measures toward elimination via mailed questionnaires. The response rate was 88% and some steps toward elimination had been taken in 83 dwellings. For the remaining houses, no improvements had been made either because of financial problems, lack of technical advice, or doubts about radon daughter exposure as a health hazard. The results of this study suggest the need to more definitely assess the risk through epidemiologic studies, as well as to provide more information about technical solutions and financial support to house owners.