<p> Indoor Air Quality: Comfort and Health</p><p>1. Human Comfort</p><p>1.1 Comfort Factors</p><p>(1) Activity(metabolic heat generation) (2) Clothing (3) Temperature of surrounding air (4) Humidity of surrounding air (5) Relative velocity of surrounding air (6) Radiation </p><p>Activity</p><p>Metabolism: heat generation rate at which energy is converted from chemical to thermal form within the body.</p><p>Blood circulation near the skin surface: heat transfer rate at which the thermal energy if carried to the skin surface.</p><p>Respiration: air is taken in at ambient condition but leaves saturated with moisture at the body temperature.</p><p>Sweating: evaporative heat transfer from skin.</p><p>Standard unit: metabolic rate of a sedentary (seated and quiet) person.</p><p>1 met = 18.4 Btu/hr-ft2 = 58.2 W/m2.</p><p>Clothing</p><p>Clothing insulation: single equivalent uniform layer of the whole body.</p><p>1 col = 0.880 F-ft2-hr/Btu = 0.155 m2-K/W Radiation</p><p>Thermal radiation between a person and the surroundings, determined by Mean Radiant Temperature.</p><p>4 4 1/2 Tmrt = Tg + CV (Tg – T)</p><p>Tg: globe temperature (from Vernon’s globe thermometer).</p><p>V: air velocity</p><p>C = 0.103  109 (IP) = 0.247  109 (SI)</p><p>1.2 Comfort Zones and Design Conditions</p><p>Effective Temperature (ET*): temperature of an environment at RH=50% that results in the same total heat loss from the skin as in the actual environment.</p><p>Standard Effective Temperature (SET) is defined under typical indoor conditions:</p><p>0.6 clo; 1.0 met; V < 20 fpm; T = Tmrt; and moisture permeability index = 0.4 </p><p>Acceptable operative temperature for active persons (for 1.2 < met < 3)</p><p>Tactive(F) = Tsedentary(F) – 5.4 (1 + clo)(met – 1.2) or</p><p>Tactive(C) = Tsedentary(C) – 3.0 (1 + clo)(met – 1.2)</p><p>2. Common Contaminants</p><p>2.1 Gaseous contaminants</p><p>CO2, CO, SO2, NOx, Radon, VOCs (volatile organic compounds)</p><p>Resources: fuel combustion, pesticides, building materials, paints, etc.</p><p>2.2 Suspended particulate (aerosol)</p><p>Soot, smoke, dust/fine powder (e.g., cement), mist spray (e.g., perfume)</p><p>2.3 Ways of control</p><p>(1) Source elimination (2) Air cleaning or treatment (filtration) (3) Dilution with outdoor air</p><p>3. Air Cleaning or Treatment</p><p>3.1 Gas contaminants</p><p>Adsorption: Coating of activated carbonate on filters Chemical/physical absorption column Spray of liquids (wet scrubber)</p><p>3.2 Particulate contaminants</p><p>(1) filtration (cake or in-depth) (2) cyclone (3) electrostatic precipitator (4) gravity sedimentation (5) wet scrubber 4. Dilution with Outdoor Air</p><p>5. Pressure Drop and Filter Selection</p>