Smog alerts' are issued by EPA to assist the public and industry. Photochemical Smog is more likely to occur in summer and early autumn with smog days of poor visibility more likely in autumn and winter. Summer 'smog alerts' are issued when a light easterly, north easterly or north wind is to be followed by a weak sea breeze in the afternoon and when there is a strong temperature inversion at less than 1000 metres above the ground. Winter 'smog alerts' are issued when light wind, low cloud cover and a temperature inversion are predicted which will result in the accumulation of airborne particles in the lower atmosphere. On 'smog alert' days, industry is asked to minimise emissions as much as possible, motorists are asked to take public transport rather than drive their cars and householders are urged not to burn off outdoors.
Most local councils have restrictions on burning off.
On 'smog alert' days, people with respiratory or cardiac disorders should take their medication and minimise their outdoor activities. Overall smog levels are slowly declining due to the impact of control programs such as the unleaded petrol strategy. All new passenger cars manufactured after 1 February 1986 have to conform to stricter emission limits and run on unleaded petrol. It was most recently updated in February 1999 to formally adopt national air quality standards developed in 1998. This review includes consultation with industry and the community.