Since its inception in the 1960’s the Association’s air quality program has tracked sulphur dioxide levels in local air. For the past 20 years, sulphur dioxide levels in Sarnia and Corunna have also been an integral part of the unique Lambton Industry Meteorological Alert (LIMA).
LIMA is an area-wide approach to maintaining acceptable air quality during periods when emissions under poor dispersion conditions could lead to locally high concentrations of SO2. The regulation is designed to maintain the daily average SO2 concentration below the Ontario Ambient Air Quality Objective of 100 parts per billion (ppb).
When it appears that the 24-hour average at a monitoring station will rise above 70 ppb, industries which emit quantities of SO2 that are capable of impacting the air we breathe, switch to fuels that contain less sulphur dioxide. Rates of manufacturing products may also be cut back in order to reduce SO2 emissions. Higher than average hourly SO2 concentrations generally occur when southerly to southwesterly winds greater than 15 km/h persist.