Typical Indoor Air Contaminants Department of Mechanical, Aerospace, and Manufacturing Engineeri Department of Mechanical, Aerospace, and Manufacturing Engineering ng College of Engineering and Computer Science College of Engineering and Computer Science � Inorganic gases Syracuse University Syracuse University � CO, CO2, SO2, NOx, O3, etc…. � Organic gases Indoor Air Quality (IAQ) Strategies Indoor Air Quality (IAQ) Strategies � Volatile organic compounds (VOCs) --- Source Control, Ventilation or --- Source Control, Ventilation or - Formaldehyde, benzene, toluene, styrene, 1,4- Air Purification? Air Purification? dichlorobenzene, 4-phenyl cyclohexene (4-PC), nonane, decane, undecane, dodecane, etc…. By � Radioactive gases (e.g., Radon) Jensen Zhang � Particulate pollutants Building Energy and Environmental Systems Laboratory (BEESL) � Bioaerosols derived from http://EnergySystems.syr.edu - Virus, bacteria, fungi, protozoa, dust mites, pollen http://www.eqstar.org - Asbestos, dusts, etc…. http://www.coees.org J.S. Zhang, 7/7/04 2 Typical contaminant sources: outdoors Typical contaminant sources: indoors J.S. Zhang, 7/7/04 3 J.S. Zhang, 7/7/04 4 1
Principle of IAQ Control Principle of IAQ Control � Goal: Ventilation Ventilation Air diffuser jet Return/exhaust Air diffuser jet Return/exhaust Q, C s C C < C criteria � Governing equation: Flow entrainment & mixing R Indoor Indoor emissions emissions C = indoor concentration C = indoor concentration V dC/dt = R(t) – Q(t) [C(t) – C s (t)] – F(t) V = room/building volume V = room/building volume Rate of Rate of Rate of Rate of Rate of Rate of Rate of Rate of = = – – dilution by – contaminant contaminant source source dilution by – reduction by reduction by accumulation accumulation emission emission ventilation ventilation F purification purification Air filtration/purification Air filtration/purification J.S. Zhang, 7/7/04 5 J.S. Zhang, 7/7/04 6 IAQ Control Building Material Emissions � Goal: C < C criteria � Strategies � Source/emission control � Ventilation � Air purification (cleaning/filtration) J.S. Zhang, 7/7/04 7 J.S. Zhang, 7/7/04 8 2
Why Study Material Emissions? VOCs from Three Oil-based Wood Stains T IC : [ B S B 1 ]W S 1 - H S 1 .D A b u n d a n c e � 300+ VOCs identified (accounts for over 50% decane WS3 1 5 1 .5 e + 0 7 1 .4 e + 0 7 nonane 1 .3 e + 0 7 1 .2 e + 0 7 5 indoor contaminants) 1 .1 e + 0 7 2-butanone 1 e + 0 7 1 1 9 0 0 0 0 0 0 1 1 6 undecane 8 0 0 0 0 0 0 9 8 7 1 0 7 0 0 0 0 0 0 � Many VOCs can cause discomfort and 2 0 6 0 0 0 0 0 0 3 1 8 1 3 5 0 0 0 0 0 0 1 7 1 4 4 1 9 4 0 0 0 0 0 0 6 2 1 2 3 0 0 0 0 0 0 adverse health effects 2 0 0 0 0 0 0 1 0 0 0 0 0 0 0 T i m e - - > 2 6 .0 0 2 8 .0 0 3 0 .0 0 3 2 .0 0 3 4 .0 0 3 6 .0 0 3 8 .0 0 T I C : [ B S B 1 ] W S 5 - H S . D A b u n d a n c e 1 . 8 e + 0 7 � Indoor VOC concentrations are usually much 1 7 1 . 7 e + 0 7 WS6 1 . 6 e + 0 7 1 . 5 e + 0 7 5 1 . 4 e + 0 7 9 1 . 3 e + 0 7 1 . 2 e + 0 7 1 3 higher than outdoors 1 . 1 e + 0 7 8 1 e + 0 7 6 1 1 1 2 1 6 9 0 0 0 0 0 0 1 5 1 9 8 0 0 0 0 0 0 1 3 4 7 0 0 0 0 0 0 1 8 2 0 6 0 0 0 0 0 0 2 1 4 1 0 5 0 0 0 0 0 0 7 4 0 0 0 0 0 0 3 0 0 0 0 0 0 2 0 0 0 0 0 0 1 0 0 0 0 0 0 T m i e - - > 0 2 6 . 0 0 2 8 . 0 0 3 0 . 0 0 3 2 . 0 0 3 4 . 0 0 3 6 . 0 0 3 8 . 0 0 T I C : [ B S B 1 ] W S 5 - H S 1 . D A b u n d a n c e 8 2 . 1 e + 0 7 2 e + 0 7 1 . 9 e + 0 7 1 . 8 e + 0 7 WS9 1 . 7 e + 0 7 1 . 6 e + 0 7 1 3 1 9 1 . 5 e + 0 7 1 2 1 . 4 e + 0 7 9 1 . 3 e + 0 7 7 1 . 2 e + 0 7 1 6 1 . 1 e + 0 7 1 1 1 e + 0 7 1 4 4 1 5 9 0 0 0 0 0 0 1 5 6 8 0 0 0 0 0 0 1 0 1 8 2 1 7 2 0 7 0 0 0 0 0 0 3 6 0 0 0 0 0 0 5 0 0 0 0 0 0 4 0 0 0 0 0 0 3 0 0 0 0 0 0 2 0 0 0 0 0 0 1 0 0 0 0 0 0 T i m e - - > 0 2 6 . 0 0 2 8 . 0 0 3 0 . 0 0 3 2 . 0 0 3 4 . 0 0 3 6 . 0 0 3 8 . 0 0 J.S. Zhang, 7/7/04 9 J.S. Zhang, 7/7/04 10 VOCs from Two Water-based (Latex) Paints Particleboard (at t=24 h, by GC/FID) PT4 T IC : 9 8 0 2 0 9 - 6 .D 9 1 1 1 1 2 2 2 2 3 3 3 3 4 4 4 A b u n d a n ce 2-methyl 2-propanol 1 4 5 0 0 0 0 P T 4 ( L a te x ) - H e a d s p a ce 4 0 0 0 0 0 2 - m e th y l 2 - p r o p a n o l 3 5 0 0 0 0 3 0 0 0 0 0 2 5 0 0 0 0 1 Hexanal 2 0 0 0 0 0 2 α -Pinene 2 1 5 0 0 0 0 acetone 1-butanol 3 a ce to n e 1 0 0 0 0 0 1 - b u ta n a l 3 Camphene 6 5 0 0 0 0 β -Pinene 4 0 T im e - - > 5 .0 0 1 0 .0 0 1 5 .0 0 2 0 .0 0 2 5 .0 0 α -Terpinene 5 PT6 T IC : 9 8 0 2 0 9 - 7 .D A b u n d a n ce 6 Limonene P T 6 ( L a te x ) - H e a d s p a ce 5 1 8 0 0 0 0 γ -Terpinene 7 acetone 4 1 6 0 0 0 0 n-butyl ether 1 4 0 0 0 0 a ce to n e n - b u ty l e th e r 7 1 2 0 0 0 0 ethyl acetate 1 0 0 0 0 0 0 e th y l a ce ta te 8 1 1 1 1 1 2 2 2 2 2 3 3 3 3 3 4 4 4 4 8 0 0 0 0 6 0 0 0 0 F i l e n a m e : D 0 4 : \ R R U E S N E A R C H \ M E \ D R Y _ P R O D \ W O O D \ P A R T B O ~ 1 \ P B 0 4 \ P B 0 4 - C h a n n e l : A = F I D 4 0 0 0 0 2 0 0 0 0 0 T im e - - > 5 .0 0 1 0 .0 0 1 5 .0 0 2 0 .0 0 2 5 .0 0 J.S. Zhang, 7/7/04 11 J.S. Zhang, 7/7/04 12 3
Full-scale Environmental Chambers Emission Characteristics “Wet” coating materials: Range of Individual VOC Emission Rates (Zhang et al. 1998) � High initial emission rates and fast decay rate � Three emission periods � evaporative controlled High initial period Low � transition period � diffusion controlled final period � Affected by air velocity J.S. Zhang, 7/7/04 13 J.S. Zhang, 7/7/04 14 Emission Characteristics Minimization of Source Emissions � Material selection Dry materials: Range of Individual VOC Emission Rates (Zhang et al. 1998) � Low emission rates � Pre-conditioning and slow decay rate High � Encapsulation/sealing � Diffusion controlled � Reformulation process � Oil versus water-based paints � Not significantly Low affected by air � Change of manufacturing processes velocity � Recycled tire materials—temperature control J.S. Zhang, 7/7/04 15 J.S. Zhang, 7/7/04 16 4
Strategies for IAQ Control Adequate Ventilation for IAQ � Outdoor air quality � Source/emission control � Amount of outdoor air � Ventilation � Room air distribution � Air purification � Delivery of outdoor air to the occupied spaces “ASHRAE Standard 62-1999: Ventilation for Acceptable Indoor Air Quality” J.S. Zhang, 7/7/04 17 J.S. Zhang, 7/7/04 18 Outdoor Air Quality: Outdoor Air Quality (ASHRAE 62-99) National Primary Ambient-Air Quality Standards* � Satisfy EPA National Primary Ambient-Air Quality Long Term Short Term Standards ug/m 3 (ppm) Averaging ug/m 3 (ppm) Averaging � Conduct air sample analysis for specific SO 2 80 (0.03) 1 year 365 (0.14) 24 hours contaminants of importance PM10 50 1 year 150 24 hours CO 40,000 (35) 1 hour � Reduce outdoor air supply temporarily (e.g., during rush-hours) CO 10,000 (9) 8 hour NO 2 100 (0.055) 1 year � Use air purification devices O 3 235 (0.12) 1 hour Hydrocarbons 160 (0.24) 3 hour Lead 1.5 3 months * Set by U.S. Environmental Protection Agency (EPA) J.S. Zhang, 7/7/04 19 J.S. Zhang, 7/7/04 20 5
Amount of Outdoor Air (ASHRAE 62-99) Adequate Ventilation for IAQ � Prescriptive procedure � Outdoor air quality Max. Occupancy CFM (L/s) � Amount of outdoor air Application (P/1000 ft 2 or 100 m 2 ) per person � Room air distribution Office space 7 20 (10) � Deliver fresh air to occupants Classroom 50 15 (7.5) � Remove/dilute contaminants Residential living area: 15 (7.5) (& not less than 0.35 air changes per hour) � IAQ procedure (performance based, allows for integration and optimization) J.S. Zhang, 7/7/04 21 J.S. Zhang, 7/7/04 22 Mixing Ventilation Displacement Ventilation Diffuser air jet Return outlet Upper zone Return outlet C out C C out C out out C in C in Stratification level Flow entrainment & mixing Thermal plume C C C Lower zone with C minimal mixing C in C in Low velocity diffuser ) ≈ ≈ C /C ≈ ≈ 1.0 Ventilation Efficiency=(C Ventilation Efficiency=( C out out - -C C in in )/(C )/(C- -C C in in ) C out out /C 1.0 ) ≈ ≈ C Ventilation Efficiency=(C C out -C C in )/(C- -C C in C out /C > 1.0 Ventilation Efficiency=( out - in )/(C in ) out /C > 1.0 J.S. Zhang, 7/7/04 23 J.S. Zhang, 7/7/04 24 6
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