The National Natural Science Foundation of China (NSFC) has been promoting its systematic reform since 2018. The adjustment of the application code is the starting point for the reform of optimizing the discipline layout. With the support of strategic research projects, the Working Group optimized and adjusted the application code of the atmospheric sciences discipline and its subordinate research directions and keywords. D0514 (atmospheric environment and health meteorology) is adjusted from the original secondary application code D0513 (atmospheric chemistry and the atmospheric environment) and belongs to the “development field” section in the new application code. It extends the knowledge chain and connotation of the atmospheric environment and is conducive to the cross-integration of different research directions. This paper combs the overall framework of D0514 research directions, explains the keyword settings of each research direction, and proposes precautions for fund applicants in selecting research directions and keywords. D0514 has four research directions, namely, the atmospheric environment and air pollution prevention, indoor air pollution, atmospheric environment epidemiology and toxicology, and health economic loss assessment. These four research directions are not only mutually supportive and closely related but also clearly distinguishable. Based on the perspective of research objects, research methods, and scientific issues, each research direction has approximately 20–30 keywords. The keywords should not be too detailed. To improve the efficiency of artificial intelligence in selecting grant reviewers, the applicant should give priority to the keywords provided by the NSFC system. By interpreting this article, the scientific community can understand the establishment process of research directions and keywords under the application code to better select the corresponding research directions and keywords for applicants.