Kharkiv state medical university Department Hygiene and Ecology №1 Subject: Hygiene of atmospheric air. Physical and chemical properties of the air, their significance. Natural radiation and its hygienic significance. Kharkiv

The lecture material  - The atmosphere as a factor in the environment. Its structure, composition and characteristics;  - The chemical composition of the air;  - Physical properties of air;  - Temperature, humidity, air velocity;  - Natural radiation and its hygienic value;  - Ultraviolet radiation properties and its effect on the human body.

Significance of

Chemical Composition of Air, p. 2 Neon-- Ne % Methane -- CH % Helium -- He % Krypton -- Kr % Hydrogen -- H % Xenon -- Xe % Ozone -- O % Nitrogen Dioxide -- NO % Iodine -- I % Carbon Monoxide-- CO -- trace Ammonia -- NH 3 -- trace Water vapor Air can contain as much as 5% water vapor, more commonly ranging from 1- 3%. The 1-5% range places water vapor as the third most common gas (which alters the other percentages accordingly).

 Forms atmospheric pressure There is so much nitrogen in our atmosphere that it adds extra mass to the air. Too much or too little pressure can have a serious effect on us if we are unprotected. Deep sea divers, like oil rig workers, experience high amounts of pressure when they are deep in the ocean. The surrounding water squeezes their bodies and they must wear special suits to protect themselves from getting squashed. Astronauts in space must also wear special suits. In space, there is so little pressure around them that the air in their lungs would rush out and their bodies would puff up like a balloon. Significance of Nitrogen

 Nitrogen forms the building blocks of proteins (we need proteins because they make up our skin and hair. Proteins also help us digest food) The nitrogen cycle is one of the important systems for living things. Bacteria take nitrogen out of the air and change it into nutrients in the soil Those nutrients help plants grow Animals eat plants The animals return nitrogen to the soil through their waste. Plants and animals also return nitrogen into the soil with their bodies when they die The cycle is completed when other bacteria process the plant and animal material and release nitrogen back into the soil and air.

 Takes part at all important vital oxidizing processes Oxyhaemoglobin (94-96% of oxygen ) Significance of oxygen Pulmonary alveoli Blood All systems and cells

Neurotoxic form characterised by convulsions followed by unconsciousness, occurring under hyperbaric conditions Oxygen toxicity Pulmonary form characterised by difficulty in breathing and pain within the chest, occurring when breathing elevated pressures of oxygen for extended periods

 CO2 is physiological activator of the respiratory center  Carbon dioxide in the atmosphere does not absorb the incoming visible radiations coming from the sun blocks the out going infrared radiations radiated by earth. By absorbing infrared radiations, the atmosphere gets heated. This is known as Green house Effect. The heated atmosphere keeps the earthworm. Thus carbon dioxide helps in keeping the earth warmer by blocking the infrared radiations.  The plants utilize carbon dioxide during the process of photosynthesis.  Ocean absorbs carbon dioxide from the atmosphere to form carbonate rocks (22% of the total amount of CO2)  Climate change effect Significance of Carbon dioxide

 Volcanic eruptions  Respiration by living organisms  Decay of organisms  Burning of fossil fuels  Cultivation of land. The major suppliers of carbon dioxide

Air Pollution

Sources of air pollution

Cancer

Solar radiation in nature

Natural and ultraviolet radiation Solar radiation Infra-red rays 760 nm and more Ultra-violet 200 nm – 400 nm Visible light 400 nm to 760 nm a) wavelength of nm b) wavelength of nm

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