This depends on exhalation or inhalation. If you are exhaling the pressure would be greater inside the lungs than the outside, but if you are inhaling, then the pressure would be greater on the outside than the inside.
when air moves out of the lungs, the air pressure decreases
Inspiration happens when the pressure inside the lungs is lower than the atmospheric pressure (outside) and air rushes into the lungs. Expiration is when the air inside the lungs is higher than the atmospheric pressure and the air rushes out of the lungs. If the intrapleural pressure (pressure within the pleura of the lungs) isn't maintained then the pressure in the lungs can't differentiate between inspiration and expiration and so the lung collapses.
The pressure inside the lungs decreases as the ribcage moves out and up. Air from outside basically gets pushed in by other air molecules due to the pressure gradient (air moves from a high pressure to a low pressure)
When pressure inside the lungs is lower than outside, air flows into the lungs to equalize the pressure. This is known as inhalation, where the diaphragm contracts and the rib cage expands to create more space for air to enter the lungs.
reduces intra-thoracic pressure which creates suction that draws air into lungs
The act of inhaling is to create low pressure in the lungs, causing the air in the atmosphere to rush in as it is moving from a higher pressure (outside in the atmosphere) to the lower pressure (created in the lungs). However the fact that air does move into the lungs means that there is no net change in pressure.
when pressure inside the lungs is lower then outer atmosphere
You use the respirerotry system. To be precise when air is to be sucked in, the brain askes the lungs to expand, which naturally creates a low pressure inside the lungs. Similarly when the lungs are compressed the air inside is flushed out.
Air goes into or out of the lungs due to differential pressure. On inhalation, the pressure within the lungs is below atmospheric, so outside air rushes in. On exhalation, the pressure within the lungs is above atmopheric, so inside air rushes out. When you stop breathing for the moment at the end of exhalation, or when you transition from inhalation to exhalation at the end of inhalation, there is no air flow, because there is no differential pressure. Assuming that you do not close your larynx, then, when the lungs are at rest, the air pressure in the lungs is the same as atmospheric, and this occurs twice in each complete breathing cycle.
a region of low pressure is created inside the lungs when compared to the outside atmosphere .When air is drawn inside air pressure is increased.
When you inhale, the diaphragm and intercostal muscles contract, expanding the chest cavity. This expansion increases the volume of the lungs, causing a decrease in air pressure within them. Air moves from an area of higher pressure (outside the body) to an area of lower pressure (inside the lungs), resulting in inhalation.
The intrapulmonary pressure is the pressure in the alveoli. Intrapulmonary pressure rises and falls with the phases of breathing, but it ALWAYS eventually equalizes with the atmospheric pressure.