Strep throat Strep throat is a throat infection causing symptoms including a red sore throat with white patches. Hay fever Hay fever, an allergic reaction to outdoor pollens and molds, causes nasal congestion, itchy eyes, and more.
Air Density is the mass per unit volume of the air. For example, the standard air density at sea level is 1.225 kg/m 3 (0.076474 pounds/ft 3). Relative Density is the ratio of the actual air density to the standard sea level density, expressed as a percentage.
pressure at any given height is called an air mass. A single air mass may spread over millions of square kilometers and be up to 10 kilometers deep. Types of Air Masses Scientists classify air masses according to two characteristics: temperature and humidity. Four major types of air masses influence the weather in North America: maritime tropical, continental tropical, maritime polar, and continental polar. The characteristics of an air mass depend on the temperatures and moisture content of the region over which the air mass forms. Remember that temperature affects air pressure. Cold, dense air has