Thus far, we have 1) defined the scope of the problem ( factors in the environment affect health of population in the environment), 2) defined the scales of the problem (personal, local, global), and 3) identified indicators of change (decreased longevity and decreased functionality). We can now formulate a means to monitor and measure the problem and attempt to implement controls where possible. Control can occur 1) if the problem is well defined such that any means or any resources to minimize, remove or reverse the effect can be identified, 2) if the identified resources exist and 3) if the means is possible.