Research and identify specific messaging that ties clean air, clean water, and clean lands to the improvement of or protection of human health. Oftentimes when discussing sustainability and environmental protection specifically, an emphasis is placed on protecting resources for the sake of the resources without adequate recognition of the fact that protecting natural resources greatly benefits human health. This might be expanded to include the social/health benefits people receive from being out in nature.
A short list of resources are included below as the best places to start researching this topic. Try searching for concepts such as public health or human health combined with recreation or outdoors.
Your search might look something like: ("public health" or "human health") AND (recreation or outdoors or natur* or environment*)
Find more about developing a search strategy for additional suggestions.