In most situations there will not be enough capacity to undertake all the desirable actions of a National Environmental Health Action Plan (NEHAP) at one time: some proposals will have to be given priority over others. Cost-benefit analysis may play a part and equity will also be a consideration.
Choosing priority actions can have two aspects: what to choose; and when to do it. This split applies to the range of proposals as a whole and to possible stages within proposals for large works or for longer term projects. It is probable that a step-wise approach to the plan and its components will be necessary and desirable, which can help to deliver the greatest benefit at the earliest time at least cost.
In countries where available resources are not sufficient to deal with the problems, some means will need to be devised to select those priority actions which are to be tackled first. Cost benefit analysis is a standard approach but, where improved health is the main outcome of a proposal, it may be difficult or impossible to quantify the benefit. Then the issue may resolve itself into choosing the least cost means of achieving a desired outcome. In many cases, actions proposed on environmental grounds, for instance in a National Environmental Action Plan (NEAP), will also benefit environmental health and vice versa. Such combined benefits may justify or prioritise action which would not be justified for either purpose considered separately.
One benefit of the process of drawing up a NEHAP is that it provides a framework for identifying high-priority projects or initiatives that the government will implement as part of national reforms and to solve agreed problems. These projects are not an additional burden on a country's economy but a means of reducing burdens and delivering benefits.
In accordance with the principle of subsidiarity, a "bottom-up" approach to prioritizing international activities should be the norm. In this context, the national priorities identified in NEHAPs should be the starting point when defining priorities for international activities in the field of environmental health.
Political involvement in priority-setting is essential. At the national, regional and local levels, there are almost always insufficient financial, human and other resources to address all identified environmental health (EH) needs. Therefore, a sensible precursor to project implementation is a procedure to establish which EH issues should be tackled as a priority in the short, medium and longer terms.
At the national level, WHO has been working with governments to develop NEHAPs based on analyses of available health and environment data. A key feature of every NEHAP is the establishment of a national priority list of EH needs. In turn, sometimes subsequently and sometimes independently, local EH planning initiatives define local EH priorities and become the "blueprint" for local activities. Where national and local priorities coincide, it is likely that national resources will be more easily mobilized. Where they do not coincide, however, national bodies may become a barrier to implementation, rather than a facilitator. Exercising the political skill of weighing up the arguments about competition for resources between national, regional and local levels is an important role for elected local government members.
Economic analysis, by providing arguments for environmental health improvements, can help set priorities for policies and actions. The Republic of Moldova's national environmental action plan, supported by the World Bank, used economic analysis for priority-setting. In particular, it applied cost-benefit analysis to establish environmental priorities, including health improvements as well as natural resource conservation and ecosystem preservation.
An explanation of the rationale for establishing priorities from many disparate potential actions would be likely to enhance public understanding and acceptance of the proposals.