UNIT 3 Environmental Science, Environmental Health, and Sanitation Environmental Science. ✅ Definition: Environmental science is the study of the interaction between humans and their environment, focusing on how environmental factors affect health, wellbeing, and disease prevention. ✅ Relevance to Nursing: ✅ Key Components: 🔷 2. Environmental Health in Community Health Nursing ✅ Definition: Environmental health is a branch of public health that focuses on how the environment affects human health