Indoor Air Quality Modeling

Purpose of Indoor Air Quality Modeling To estimate the indoor air pollutant concentration in a building To estimate the indoor air pollutant concentration in a building To determine the indoor air quality inside a building To determine the indoor air quality inside a building For development and evaluation of source-to-dose models of persistent pollutants For development and evaluation of source-to-dose models of persistent pollutants

Types of Air Quality Models One – Compartment models One – Compartment models Multi Compartment models Multi Compartment models Empirical models Empirical models

Mass Balance Model Given by Q 0 +Q 2 =Q 3 +Q 4 Given by Q 0 +Q 2 =Q 3 +Q 4 Mass Balance Indoor Outdoor Model Mass Balance Indoor Outdoor Model Infiltration from outdoors Q 2 F0F0 F1F1 Make Up Air Q 0 Re - circulation Q 1 Room Volume (V) Mixing factor k Source S Decay R Exfiltration Q3 Exhau st Q 4 F 0 & F 1 are filter efficiency

Pollutant Mass Balance V(dC 1 / dt) = k x Q 0 x C 0 (1 – F 0 ) + k x Q 1 x C 1 (1 – F 1 ) + k x Q 2 x C 0 + S – R- k (Q 0 + Q 1 +Q 2 )Ci V(dC 1 / dt) = k x Q 0 x C 0 (1 – F 0 ) + k x Q 1 x C 1 (1 – F 1 ) + k x Q 2 x C 0 + S – R- k (Q 0 + Q 1 +Q 2 )Ci For t = 0, Ci = C For t = 0, Ci = C R = E x Ci R = E x Ci Also t tends to infinity Also t tends to infinity Ci,ss = ((k x [Q 0 x C 0 (1 – F 0 ) + Q 2 ]C 0 ) + S) / ((Q 0 + Q 1 +Q 2 ) + E) Ci,ss = ((k x [Q 0 x C 0 (1 – F 0 ) + Q 2 ]C 0 ) + S) / ((Q 0 + Q 1 +Q 2 ) + E) Where, Ci,ss = Steady State concentration Where, Ci,ss = Steady State concentration

Notations Q 0 = Make up air Q 0 = Make up air Q 1 = Indoor air Recirculation Q 1 = Indoor air Recirculation Q 2 = Infiltration from outdoors Q 2 = Infiltration from outdoors Q 3 = Exfiltration Q 3 = Exfiltration Q 4 = Exhaust Q 4 = Exhaust F0 = Filter efficiency F0 = Filter efficiency F1 = Filter efficiency F1 = Filter efficiency Co= Outside Concentration Co= Outside Concentration

Notations Ci = Indoor Concentration Ci = Indoor Concentration V = Room Volume V = Room Volume K = Mixing factor K = Mixing factor S = Source emission rate S = Source emission rate R = Decay of Pollutant R = Decay of Pollutant