Global trends and European emissions of tetrafluoromethane (CF&amp;lt;sub&amp;gt;4&amp;lt;/sub&amp;gt;), hexafluoroethane (C&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;F&amp;lt;sub&amp;gt;6&amp;lt;/sub&amp;gt;) and octafluoropropane (C&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt;F&amp;lt;sub&amp;gt;8&amp;lt;/sub&amp;gt;)