Hypercapnia is an unusually high concentration of carbon dioxide in the blood which may be accompanied by hypoxemia, in which the oxygen level in the blood is low. This condition occurs as a result of poor gas exchange at the lungs which makes it difficult for people to eliminate carbon dioxide from their bodies.
Quick Answer. A tire treadwear rating refers to the amount of time the treads on a tire should last in specific conditions. Tire manufacturers indicate treadwear rating on their tires using a set of numbers between 100 and 700. These numbers indicate how long tire treads will remain safe and perform at their highest capacity.
Spotting abnormal tire wear and correcting the cause can significantly extend tire life. Normally, tires will wear evenly across their surface until they reach the wear bars, which are 2/32nds of an inch above the bottom of the tread. When the tires are worn to the wear bars, they should be replaced.