An odour can be defined as a smell that is detectable. People have different abilities and tolerances of odours, and as such, we are faced with the difficult task of establishing whether the odour is bad enough to cause a 'nuisance' or simply causes annoyance. There are no specific laws that relate specifically to odour, nor is there a fixed level which constitutes a statutory nuisance. Individual circumstances differ, and each case has to be judged on its own merits. Complaints of odour which includes smokes, fumes, or gases are investigated under the Environmental Protection Act 1990. In determining whether an odour causes a statutory nuisance, it has to be proven that the odour:
1. Occurs frequently;
2. Is unreasonably strong;
3. Lasts for long periods at a time
In practice the odour would have to be a persistent problem interfering substantially with your well being, comfort or enjoyment of your property.
Specific Odours Examples:
1. Odours from commercial processes
Any industrial or commercial operation has a defence against statutory nuisance known as the "The Best Practicable Means’ defence. This means that if they are doing everything within their financial means and within the scope of current technical knowledge to prevent causing a problem, establishing a statutory nuisance would be unlikely.
In the case of a business with an authorisation, it is the compliance with the authorisation that is assessed rather than if a nuisance exists (Authorised Processes are exempt from Nuisance Legislation).
2. Odour from the land
In dealing with complaints relating to the spreading of manure or slurry on the land. Environmental Health Departments follow the informal advice provided by the Ministry of Agriculture Fisheries and Food (MAFF), which is that "manure or similar should be ploughed in within 72 hours of it being spread". It is accepted that there is to be a certain degree of odour arising from this activity. If odours are experienced after this period and its source is identifiable, Environmental Health Departments can instigate to establish whether it is whether it is causing a statutory nuisance.