Unfortunately, we don’t have published methodologies for environmental impact assessment. Environmental impact assessment is about analyzing and understanding the environmental implications of projects prior to construction. For example, a new airport must be built and there are several possible locations. What can be the environmental consequences of building and operating an airport at each of those possible locations? ISO 14001 is about organizations already operating and the focus is on performing an environmental assessment to determine environmental aspects and impacts.
The following material will provide you more information about aspects and impacts: