This paper discusses the environmental pollution and toxic effect of chemical pollutants pro-duced by straw burning, such as particles, PAHs, NO₂and SO₂ etc. It can help people know the harm of straw burning, strengthen environmental protection consciousness, and utilize straw.

This paper introduces some applications of nanomaterials, and some research results of biological effect and toxicology of some nanomaterials such as nano-TiO₂, carbon nanotubes,and nano-sized iron powder etc. Furthermore,it discusses the potential effects of nanomaterials on human body and environment,the research focus of nanomaterials toxicity in the future,and the prospect of nanomaterials safety.

Calcium carbonate is a very common nonmetal material that exists in nature widely, and is a traditional inorganic salt product of chemical industry. In recent yeas, with the development of superfine and surface modification technology, the preparation of nanon calcium carbonate and its application is the research focus at home and abroad. This paper introduces the main producing technologies of nanon calc-i um carbonate and their applications.