Air is one of the first terms that students encounter in primary science classes. On the other hand, environmental problems of air pollution are present in the daily life of many people, and environmental awareness is developed and nurtured at all levels of education. Air is omnipresent in the lives of children from the earliest age, but due to its invisibility and intangibility, there are difficulties in understanding and adopting the concepts of air and its physical properties. Hence, these difficulties were the subject of this research. The aim of the research was to evaluate the level of adoption of teaching content about air among students in lower grades of primary schools, as well as, to assess whether and to what extent the teaching of the subjects The World Around Us and Nature and Society affects the development of concepts about air. 140 students of lower grades (I-IV) of two primary schools participated in the research. A knowledge test of twelve tasks related to scientific facts about air and its properties was applied. The obtained results show that there are no statistically significant differences in the level of adoption of tested scientific terms depending on the class (age), which points out to the conclusion that the process of developing certain scientific terms about air is insufficiently effective in the initial teaching of natural sciences. It is recommended to apply some innovative teaching models and strategies when processing teaching content about air, and to connect this content to everyday phenomena and students’ experiences as often as possible.