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.
With a tire tread depth gauge. Tire tread depth gauges are a fast and easy way for you to know for sure if your tires are safe or if they need to be replaced. 1  Find the shallowest groove of the tread and insert the pin of the gauge until the base is flush with the tire.  Read the scale.