Imbalance amount of oxygen in the exhaust means more pollutants to be dumped to the environment, with which people will still be the ones who would suffer the long term effect. If your Mercury is discharging black smoke that smells like rotten egg, you are contributing to the worsening of air pollution. But if you make sure that the emissions control system of Mercury is doing its job efficiently, you can make valuable contribution in slowing the progress of the environmental problem.

The Mercury oxygen sensor which is incorporated in your Mercury is an auto part that plays essential role in producing an exhaust with the least level of toxic elements. It is an electrical auto part working to determine the amount of oxygen in the exhaust for necessary adjustments. It's basically a hollow tube divided into three compartments by a U-shaped platinum-coated rod. An oxygen sensor is a mechanism that responds to the oxygen component by producing electrical signal.

Also known as O2 sensor, lambda probe, lambda sensor, lambda sond or EGO sensor, this device is positioned in the exhaust pipe where the oxygen content can be measured right before it leaves the cylinder. It checks the red-hot exhaust hundreds of times per minute in order to get the accurate amount of oxygen present, and determines whether the mixture is lean or rich. These are exhaust mixtures that do not have perfect fuel, air and hydrogen ratio, and can both result to bad exhaust quality if not given the necessary balancing. They usually indicate great amount of hydrocarbons, nitrogen oxide, and carbon monoxide in the waste product. And can contribute to poor mileage and bad performance, as well as cause early engine damage.

The computer, to which the Mercury oxygen sensor delivers the oxygen data, is the one that processes the necessary adjustments in order to correct or at least trim down the excess, and reach the level nearest to the perfect ratio. Nonetheless, perfect ratio is relative, depending on the type of engine the Mercury powered with, and of course on the type of oxygen sensor it carries. The efficiency of its job also is affected by several aspects, thus perfect ratio fluctuates. This includes altitude, air and engine temperature, barometric pressure and engine load.