Quick: Do you know how much pressure your tires are supposed to have? Do you even know the units of tire-pressure measurement?
Well, it’s stamped right there on the sidewall of your tires and usually inside your car’s door, too. Do not, as email-sender and step-suggester Susan put it, “eyeball” the tire and pretend you can tell if it had enough air or not. Also, it is measures in pounds per square inch, each of which, Google tells me, is equivalent to 6,894.75729 pascals. The more you know!