Environmental Engineering Reference
In-Depth Information
6.3 Physical Properties of Indoor Aerosols ................................................................................ 150
6.3.1 Size Distributions...................................................................................................... 150
6.3.1.1 Number ...................................................................................................... 150
6.3.1.2 Surface Area .............................................................................................. 151
6.3.1.3 Volume and Mass....................................................................................... 151
6.3.2 Particle Dynamics..................................................................................................... 152
6.3.2.1 Particle Motion........................................................................................... 152
6.3.2.2 Particle Formation and Phase Partitioning ................................................ 153
6.3.3 Surface Area in the Indoor Environment ................................................................. 155
6.3.3.1 Particles...................................................................................................... 155
6.3.3.2 Indoor Materials ........................................................................................ 156
6.3.3.3 Adsorption Indoors .................................................................................... 156
6.4 Chemical and Physical Processes Relevant to Indoor Aerosol Chemistry........................... 157
6.4.1 Reequilibration of Iniltrated Particles ..................................................................... 157
6.4.2 Neutralization of Acidic Particles............................................................................. 158
6.4.3 Emission and Partitioning of Semi-Volatile Organic Compounds ........................... 158
6.4.4 Indoor Aerosol Formation ........................................................................................ 159
6.4.4.1 Semi-Volatile Organic Compounds Reemission........................................ 159
6.4.4.2 Reactive Organics and Ozone.................................................................... 159
6.4.5 Multimedia Modeling for the Indoor Environment.................................................. 160
6.5 Fate and Transport ................................................................................................................ 160
6.5.1 Model of Indoor Aerosol Behavior ........................................................................... 161
6.5.2 Airlow and Aerosol Transport through Penetrations in Building Envelopes.......... 164
6.5.3 Indoor Aerosol Deposition Rates.............................................................................. 165
6.5.4 Resuspension Rate of Particles on Carpets/Floors................................................... 166
References...................................................................................................................................... 167
When Sherlock Holmes mystiied his friend Dr. Watson by his amazing deductions, he was utilizing to
the fullest degree the data available to him - the muddy boot, the ash of a cigar, the torn ticket. This is
a practice which is also basic in the highest forms of scientiic research.
Wilson (1952)
Research in indoor aerosol physics and chemistry requires the type of careful observations and
astute deductions that the ictional detective used so well. Holmes' perspective assists in moving
past preconceptions based on outdoor chemistry and presumptions that indoor environments provide
suficient refuge from the assaults of air pollution.
6.1
COMPARISON OF INDOOR AND OUTDOOR AEROSOLS
6.1.1 i
MPortance
oF
a
erosol
e
xPosures
Epidemiologists have established associations between exposures to ambient (outdoor) particles and
both human morbidity (disease rate) and mortality (death rate). Health effects of PM include both
chronic and acute forms of both respiratory and cardiovascular disease, among others that inluence
human life spans (Schwartz et al., 2008; Pope et al., 2009). Many of the predicted impacts of climate
change can increase exposures to both indoor and outdoor particles (Institute of Medicine, 2011).
6.1.2 s
igniFicance
oF
tHe
i
ndoor
e
nvironMent
to
a
erosol
e
xPosure
6.1.2.1 Most Exposure and Inhalation of Outdoor PM Occurs Indoors
People spend 80%-90% of their time indoors, so most human exposure to particles of outdoor
origin takes place indoors. Nazaroff et al. (2003) compared mass low rates in urban and indoor
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