The nanopascal is a multiple of the unit bit for Pressure. The prefix nano (symbol n) is defined in the International System of Units (SI) as a multiplier of 1.0 × 10-9 (1 billionth, short scale), and therefore 1 nanopascal = 1.0 × 10-9 pascals = 0.000000001 pascals. The nanopascal has the unit symbol nPa.
Inches of mercury
Inch of mercury (inHg and "Hg) is a unit of measurement for pressure. It is still used for barometric pressure in weather reports, refrigeration and aviation in the United States.