Characterization of Air Emissions | Environmental Engineering - Civil Engineering (CE) PDF Download

AIR POLLUTION 

• Air quality is affected by various economic and industrial activities which alter the composition of air and affect the environment locally, regionally and globally. 
• It is estimated that anthropogenic sources have changed the composition of global air by less than 0.01%. However, this change has adversely affected the climate of the earth. 
• Both natural and/or anthropogenic activities introduce air pollutants which can be solid (large or sub-molecular), liquid or gas into the atmosphere that pose problem to human health and other life forms on earth. 
• These air pollutants include CO, SOx, NOx, SPM, CO₂, ozone, photochemical smog, etc.. 

Classification of Air Pollutants 

• Natural contaminants: Natural fog, pollen grain, bacteria, volcanic eruption, wind blown dust, lightning generated fires. 
• Particulate (aerosols): Dust, smoke, fog, mists, fume. 
• Gases and odor: SOx, NOx, CO, CO₂, halogen compounds, hydrocarbons, radioactive compounds. 

PARTICULATE MATTER (PM) 

• PM is a complex mixture variable in size (0.01- 100 μm), composition (metals, nitrates, sulfate, polynuclear aromatic hydrocarbons (PAH), volatile organic compound (VOC), etc.) and concentration. 
• Toxicity and penetration depends on the composition and size of the particles. 
• Solid or liquid particles with sizes from 0.005 – 100 μm 
• General term is aerosols  
• Dust originates from grinding or crushing 
• Fumes are solid particles formed when vapors condense
• Smoke describes particles released in combustion processes 
• Smog used to describe air pollution particles 

Health Effects of Particulate Matter 

• Impact depends on particle size, shape and composition 
• Large particles trapped in nose · Particles >10 μm removed in tracheobronchial system 
• Particles <0.5 μm reach lungs but are exhaled with air 
• Particles 2 – 4 μm most effectively deposited in lungs 
• Inhalable PM includes both fine and coarse particles.  
• Coarse particles  
  • aggravation of respiratory conditions, such as asthma.  
• Fine particles  
  • increased hospital admissions and emergency room visits for heart and lung disease 
  • increased respiratory symptoms and disease 
  • decreased lung function 
  • premature death Other Effects of Particulate matter
• Decreased visibility 
• Damage to paints and building materials 

Table 1.8.1. Gaseous air pollutants, their properties and significance.

Table 1.8.2. Monitoring systems used to determine the quality of ambient air . 
 

Table 1.8.3. Monitoring systems can be used to monitor air emissions [2].