air 2

Chemical Composition of Air

• Air consists primarily of:

  • Oxygen: 20.9%

  • Nitrogen: 78.07%

  • Carbon Dioxide: 0.03-0.04%

  • Inert gases: Argon, Neon, Krypton, Helium, Xenon < 1%

Importance of Oxygen

• Essential for respiration in humans, animals, and plants.

• Supports combustion and oxidation.

• Essential for decay processes.

Oxygen Levels and Effects

• Severe deficiency occurs at 11-13%, with death possible at 7-8%.

• Living organisms are sensitive to even small decreases in oxygen levels.

Role of Nitrogen

• Acts as an oxygen diluent; breathing pure oxygen is harmful.

• High nitrogen concentrations (93%) can cause death through hypoxia.

Carbon Dioxide (CO2) Dynamics

• Enters air from:

  • Respiration of humans and animals.

  • Decay, fermentation, and combustion processes.

  • Release from oceans.

• Absorbed by plants during photosynthesis, washed out by precipitation, and forms mineral compounds.

Physiological Effects of CO2

• Stimulates the respiratory center.

• Levels of 4% can cause headaches and increased blood pressure; 8-10% can be fatal.

• High concentrations possible in confined spaces.

Carbon Dioxide and Pollution Indicators

• High CO2 levels indicate poor air quality in residential and public areas.

• CO2 levels in indoor spaces should not exceed 0.1%. In medical settings: 0.07%.

Ozone (O3) in the Atmosphere

• Exists in two layers:

  • Stratosphere: 90% of atmospheric ozone (ozone layer).

  • Troposphere: remaining 10%.

• High concentrations (>0.005 mg/l) cause respiratory irritation and inflammatory processes.

Inert Gases

• Chemically indifferent gases (Argon, Neon, etc.).

• Significant increases can cause narcotic effects.

• Certain inert gases contribute to natural atmospheric radioactivity.

Solar Radiation

• Composed of corpuscular (solar wind) and electromagnetic radiation.

• Electromagnetic spectrum includes:

  • Radio, Infrared, Visible, Ultraviolet, Gamma, X-ray radiation.

Wavelength and Energy of Solar Radiation

• Energy correlates with wavelength; shorter wavelengths have higher energy.

• Infrared (760-4000 nm), Visible (400-760 nm), Ultraviolet (290-400 nm).

Infrared Radiation and Hygienic Value

• Primary thermal effect; contributes to heating Earth's surface.

• Influences weather and climatic conditions.

• Shortwave penetrates deep; longwave primarily affects surface layers.

Biological Effects of Infrared Radiation

• Can increase metabolism and biological effects of UV rays.

• Used in physiotherapy.

• Prolonged exposure can cause overheating and related health issues.

Ultraviolet (UV) Radiation Types

• Three types based on wavelength:

  • UV-A: Long-wave (400-320 nm)

  • UV-B: Medium-wave (320-280 nm)

  • UV-C: Short-wave (280-210 nm)

• Only UV-A and UV-B reach Earth's surface; UV-C is absorbed by the ozone layer.

Biological Effect of UV Radiation

• Stimulates metabolism and immunity; particularly effective with UV-B.

• Essential for Vitamin D production; deficiency leads to health issues like rickets and osteoporosis.

UV Radiation Therapy

• Minimum erythema dose (MED) established for safe exposure.

• Used in treating skin conditions; caution required to prevent skin damage.

Air Pollution Sources

• Types: Gaseous, vapor, dust, microbial.

• Major sources: Industrial activities, transport.

Main Pollutants

• Sulfur Dioxide (SO2): Major pollutant from burning fuels and industrial emissions; causes acid rain.

• Carbon Monoxide (CO): Main source is motor vehicles; affects oxygen transport in blood.

• Nitrogen Oxides (NOx): From combustion processes; causes respiratory and cardiovascular issues.

Mechanical and Biological Pollutants

• Mechanical: Dust and smoke from industrial activities.

• Biological: Bacteria and viruses are airborne pathogens leading to infections.

Importance of Ventilation

• Essential for maintaining indoor air quality.

• Improves microclimate and reduces disease transmission.