Simpe truth: You can't measure atmospheric (absolute) pressure with a differential (relative) pressure sensor. An absolute pressure sensor can't work without a vacuum at it's reference port. For this reason, it's a bit more expensive than a differential type, but also available in a wide choice of types.
P.S.: A supplement. A hermeticly closed box with constant pressure would act as a thermometer, p ~ T. Refer to elementary physical laws. The only temperature independent constant pressure is zero pressure - a vacuum.