Where possible and appropriate, data have been shown over time to provide important trend information. For time trends of health effects, age-standardised rates have been used in order to control for changing age structures.
Data for many indicators have been presented at regional levels. These regions include:
Within a single environmental health issue (eg, air quality), an effort has been made to keep the level of geography consistent across indicators (eg, presenting all data at territorial authority level). However, this has not always been possible because data often come from a variety of sources and agencies and therefore have been collected for a variety of purposes and are sometimes available only at certain regional breakdowns. Data are also not always available for every region (eg, many analyses in this report have not included the Chatham Islands).
Maps showing boundaries and names of territorial authorities and DHBs are provided in Appendix C. Tables presenting demographic data about DHBs, territorial authorities and airsheds are provided in Appendix D.