Quality aspects of official environment statistics

'High quality' is a most desirable property for all data. As a basis for the discussion, the four main aspects of quality of official statistics are presented, using a form now operational at Statistics Sweden. The relevance in environment statistics is explained, and the close connection with quality control and quality assurance, as often used in the context of environmental monitoring and other environmental measurements, is explored. With this background, a number of quality problems are discussed, including the various sources of quality loss in using emission coefficients and calculations of similar character, the difficulties of defining sampling errors in data based on samples from air and water, comparability problems, not least arising from differing definitions, other definition and measurement problems, and the need to measure the quality of statistical maps. The necessity to consider the quality of aggregates, in addition to the quality of individual measurements, is stressed.