Planning of an Integrated acidification study and survey on acid rain impacts in China. Final report

The PIAC-project has been a multidisciplinary survey on acid rain in China. One goal has been to document effects of airborne acidifying compounds on vegetation, soil, soil- and surface- water and aquatic biota. Other goals have been to exchange knowledge between Chinese and Norwegian scientists, as well as visiting research sites in highly polluted areas in China and evaluating their need of support in a future collaborative monitoring and research program. Besides doing field measurements, we have collected samples at more than 20 sites in three areas in China, i.e. Chongqing, Guiyang and Guangzhou. Data from this survey may also be used in the RAINS-Asia model work, where more data are needed to validate and improve this model. Our survey documents negative effects of air pollution on all ecosystem levels investigated. The air concentration of sulfur in the urban and nearby areas is very high. The concentration of volatile organic compounds is generally high, which means that intcreased NOx emissions in coming years may create increasing O3 problems. Reduced photosynthetic activity in some plants is documented, as well as soil and surface water acidification. Aquatic biota also reflects the acidification status of the surface waters investigated. However, the degree of damage in these regions is difficult to assess, since too few sites are incorporated in the survey. Surface water acidification is currently not a major enviromental problem in China and will presumably not become one during the next decades. This report also contains a status report about acidification in China (in Appendix A) as well as a proposed framework for a monitoring program based on Norwegian experiences (in Appendix D).