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Air pollution is the introduction of airborne chemicals, particulate matter or biological materials that cause harm or discomfort to organisms. [59] The population growth , industrialization and motorization of human societies have significantly increased the amount of airborne pollutants in the Earth's atmosphere, causing noticeable problems ...
The units of air pressure are based upon the standard atmosphere (atm), which is 101,325 Pa (equivalent to 760 Torr or 14.696 psi). The height at which the atmospheric pressure declines by a factor of e (an irrational number equal to 2.71828) is called the scale height (H).
Humid air is less dense than dry air because a molecule of water (m ≈ 18 Da) is less massive than either a molecule of nitrogen (m ≈ 28) or a molecule of oxygen (m ≈ 32). About 78% of the molecules in dry air are nitrogen (N 2). Another 21% of the molecules in dry air are oxygen (O 2). The final 1% of dry air is a mixture of other gases.
Different air masses which affect North America as well as other continents, tend to be separated by frontal boundaries. In meteorology, an air mass is a volume of air defined by its temperature and humidity. Air masses cover many hundreds or thousands of square miles, and adapt to the
Atmospheric pressure, also known as air pressure or barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as 101,325 Pa (1,013.25 hPa ), which is equivalent to 1,013.25 millibars , [ 1 ] 760 mm Hg , 29.9212 inches Hg , or 14.696 psi . [ 2 ]
A difference in air pressure causes an air displacement and generates the wind. The Coriolis force deflects the air movement to the right in the northern hemisphere and the left in the southern one, which makes the winds parallel to the isobars on an elevation in pressure card. [1] It is also referred as the geostrophic wind. [2]
The density of air or atmospheric density, denoted ρ, [1] is the mass per unit volume of Earth's atmosphere. Air density, like air pressure, decreases with increasing altitude. It also changes with variations in atmospheric pressure, temperature and humidity.
An aerosol is a suspension of fine solid particles or liquid droplets in air or another gas. [1] Aerosols can be generated from natural or human causes. The term aerosol commonly refers to the mixture of particulates in air, and not to the particulate matter alone. [2] Examples of natural aerosols are fog, mist or dust.