Public health policy and environmental factors play crucial roles in protecting and promoting population health. Laws, regulations, and guidelines address issues like infectious diseases, chronic conditions, and health disparities, while environmental elements such as air quality and food access significantly impact health outcomes. Policy development involves stages from problem identification to evaluation, influenced by scientific evidence and stakeholder input. Environmental factors encompass physical, chemical, and biological conditions, with air pollution, water quality, and climate change as major concerns. Built environment and occupational health also affect public well-being.