Abstract:

The study aims to provide a reference for the future research on negative air (oxygen) ions by summarizing its research progress and frontier topics. Based on the Web of Science core database with ‘air negative oxygen ion’ as the search object, we got the literature on air negative (oxygen) ion from 2002 to 2019, and studied its development history in the 18 years through the knowledge graph. The results show that the Web of Science database includes 285 relevant documents in 2002-2019, with an average annual growth rate of 7.08% and a collaboration index of 4.54. There are many highly productive authors and highly cited articles, and articles from journals with high impact factors and with high citation counts are more likely to be cited by other authors. The major disciplines of the air negative (oxygen) ion source journals are physics, engineering technology, and chemistry, with 12 articles published in Journal of Physics D: Applied Physics, which is the largest number. Related high-frequency keywords from air negative (oxygen) ion articles are mainly about oxygen, air, performance, nitrogen, discharge, plasma and so on, the application of new energy and materials (e.g., plasma, batteries, graphene) is a hot topic in recent years. The Chinese authors have relatively a large number of published articles, citations and collaboration with authors from abroad, but their number of citations per article is relatively low. There are differences in the research field between Chinese and foreign authors. In China, the main focus is on the relationship between air negative (oxygen) ions and forest therapy and environmental factors, while in foreign countries, the application of air negative (oxygen) ions in chemistry, industry and medical treatment is the main research focus.

Key words: air negative (oxygen) ions, knowledge map, Web of Science, development trend, forest therapy, forest environment