To some, environmental concern means using non-aerosol sprays, to others it means changing our basic energy resources. Both show concern but they reflect different levels of "green-ness". When analyzing consumer behaviour, these differing attitudes need to be taken into account before drawing conclusions about public response to environmental issues. Terms like "concern", "green" and "conservation", used when assessing consumer reactions or researching markets, are often loosely defined and so produce inaccurate data. The author surveys the rise of environmental concern and examines the ways to quantify it accurately.