What factors affect atmospheric pressure?

Atmospheric pressure is influenced by several factors, and altitude, temperature, and humidity play significant roles in its variation.

As altitude increases, the density of the air decreases, leading to lower atmospheric pressure because there is less air above any given point in the atmosphere. This is why mountain tops experience lower pressure compared to sea level.

Temperature also affects atmospheric pressure; warmer air is less dense than cooler air. When air is heated, it tends to expand and rise, which can lower the pressure at the surface. Conversely, cooler air is denser and will result in higher atmospheric pressure.

Humidity, the amount of moisture in the air, also affects pressure. Water vapor is less dense than the nitrogen and oxygen that make up the bulk of the atmosphere. Thus, higher humidity levels can decrease atmospheric pressure as moist air weighs less compared to dry air.

Other factors like wind speed, while relevant in the context of weather patterns, do not directly affect atmospheric pressure in the same fundamental way as altitude, temperature, and humidity. Therefore, the correct answer effectively encompasses the key factors that directly influence atmospheric pressure.