This paper focuses on the competencies in environmental health acquired by students during compulsory education. Questionnaires addressing environmental health problems were completed by 923 students of primary and secondary schools from five different Spanish regions. The results for five challenging situations related to hunger, consumerism, climate change, pollution in the cities and allergies are analysed according to the internal coherence of each sub-competency, i.e., addressing knowledge, skills and attitudes towards these topics. Our results show that problems related to air and water pollution were the most commonly described by the students. Focusing on competency achievement, the higher the educational level, the higher the score students obtained, especially regarding pollution and climate change, two problems that appear directly in the school curriculum. The complexity of the concept of environmental health matches with the necessary holistic perspective of the Sustainable Development Goals in a polyhedral approach including as many factors (facets) as necessary to complete the approach to this evolving concept.