Chapter 7 - Air 7.0 Air 7.1 Introduction There is very little data on air quality in the Marlborough Sounds area. The general perception is that the Sounds have few air pollution problems typified by the high visual clarity of the air. The low level of concern can be attributed to the sparse distribution of people and the climatic conditions of the Sounds. There are few sources of air contaminants and the relatively strong winds and high rainfall combine to either disperse or wash out most air contaminants. Air quality concerns can be divided into three categories: global, local and nuisance. Discharge of certain contaminants can have global impacts. The most important of these to New Zealand are the discharge of ozone depleting substances and greenhouse gases. Both global warming and a depleted ozone layer have the potential to adversely affect the health and wellbeing of the people of the district. Ozone depletion can give rise to increased skin cancers in animals and humans and affect plant growth. Global warming may make existing ecosystems unsustainable and cause sea level rise. Local contamination of the air occurs through discharge of dust, smoke, odour and agrichemicals. The Act divides the control of discharges to air into two types. First discharges from industrial or trade premises are not allowed unless the discharge is expressly allowed by a rule in the Plan, resource consent, or regulations. Second, discharges from all other sources are allowed unless the discharge contravenes a rule in the Plan. The Act allows some existing discharges to continue. The rules in the Plan are directed at allowing a range of activities to continue, while ensuring that any adverse effects on air quality are avoided, remedied or mitigated. However, discharges from vessels, motor vehicles and trains are not managed by the content of the Plan. Like global air quality issues, these discharges need to be addressed as national issues. 7.2 Issue Managing air quality in the Plan area in the absence of ambient air quality information. Ambient air quality refers to the overall quality of the air and is a measure of its variation from a pristine state. As such, it is a measure of the cumulative effects of human and natural activities on air quality. Knowledge of ambient air quality is essential for an effects-based air quality management program. Without knowledge of the ambient air quality there is an inherent danger in setting standards which may in effect grant license to pollute. This would certainly be the case if air quality standards developed for major New Zealand cities were to be adopted for the Sounds area. 7 - 1