Week3studyguide.pdf

MEE 6501, Advanced Air Quality Control 1

Course Learning Outcomes for Unit III

Upon completion of this unit, students should be able to:

4. Examine causes of indoor and outdoor air pollution.
4.1 Discuss the natural variables causally related to indoor air pollution.
4.2 Discuss the anthropogenic variables causally related to indoor air pollution.
4.3 Calculate volatile organic compound (VOC) and exempt solvent (ES) values for a selected

scenario.

Course/Unit
Learning Outcomes

Learning Activity

4.1
Unit Lesson
Chapter 11, pp. 389-432
Unit III Mini Project

4.2
Unit Lesson
Chapter 11, pp. 389-432
Unit III Mini Project

4.3
Unit Lesson
Chapter 11, pp. 389-432
Unit III Mini Project

Reading Assignment

Chapter 11: Indoor Air Quality, pp. 389–432

Unit Lesson

In our last unit, we discussed the aerosol particle science of studying aerodisperse systems and included
volatile organic compounds (VOCs) as one of the significant aerosol particle families of concern in air quality.
Further, we currently understand that approximately 54% of VOCs are sourced from industrial sources, with
the remaining 46% of VOCs being sourced from highway vehicles (21%), non-road mobile sources (16%) and
stationary fuel combustion (9%) (Phalen & Phalen, 2013). In this unit, Godish, Davis, and Fu (2014) spend
considerable time explaining the implications of how these VOC sources impact indoor air quality. In to
fully understand how we can learn to anticipate organic compound pollutants within the context of indoor air
quality, we must first understand the various speciation of volatiles and semivolatiles (SVOC) from both
natural sources and anthropological sources.

Hydrocarbon Categories

Godish et al. (2014, p. 411) are careful to speciate VOCs into the following categories of hydrocarbons (HC):
(a) aliphatic, (b) aromatic, (c) halogenated, and (d) oxygenated. We are going to take a few moments to look
at each of these categorical hydrocarbons in to understand their chemical composition, sources, and
behaviors. If we can better understand each category of hydrocarbon, we can better predict—and
subsequently engineer—indoor air quality through specifically designed engineering controls. As a reminder,
hydrocarbons are simply defined as organic compounds containing only the two elements of carbon and
hydrogen, with carbon being the base element (Hill & Feigl, 1987).

UNIT III STUDY GUIDE

Engineering for Indoor Air Quality

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Aliphatic hydrocarbons are most
easily distinguished as not being an
aromatic hydrocarbon (we will discuss
aromatic hydrocarbons next). You
may recall that elemental carbon only
has four receptor sites available for
bonds in which to share up to three
electron pairs. A saturated
hydrocarbon (alkanes/paraffins)
molecule means that there are atoms
bonded to all four of the carbon
receptor sites with a simple, weak,
single bond (one pair of shared
electrons). This is easily observed
with the hydrogen atom (one receptor
site) bonded to all four of the carbon
receptor sites in methane (CH4) and
with ethane (C2H6) (Hill & Feigl, 1987).
This understanding of available
carbon receptor sites becomes
extremely important as we begin to
investigate other available gas
molecules in the human or ecological
body that come into contact with
hydrocarbons. Despite their relatively
low reactivity, if there is a receptor site
available (or a single bond that is easily broken), then there is a possibility of a chemical reaction occurring
with the hydrocarbon compound and important available gases in the body (including oxygen) becoming
unavailable for sustaining life in the human or ecological body. This is what makes hydrocarbons so
precarious when in contact with life forms (plant, animal, and human). Alkanes typically float on water as they
are insoluble in water, but are deadly as an air pollutant with their ability to dissolve fatlike molecules from the
cell membranes within the alveoli of the lung to cause chemical pneumonia (Hill & Feigl, 1987).

There are also the unsaturated hydrocarbons (alkenes/olefins) that are characterized by a stronger, carbon-
to-carbon double bond (two pairs of shared electrons). These would include ethene (CH2=CH2), propene
(CH3CH=CH2), 1-Butene, 1-Pentene (e.g., properly named ethylene, propylene). These are often easily
converted into plastics and many other intermediates for synthetics and end products (Hill & Feigl, 1987).
These aliphatic hydrocarbons are what constitute the primary reactants in the photochemical processes that
we discussed in Unit I, producing smog and haze (Godish et al., 2014). Alkenes are readily found as an off-
gas of ripening fruits and vegetables (producing ethylene), but can also be found in industrial indoor
applications such as welding (actually in cutting steel with an oxyacetylene torch) or as pure acetylene as a
general anesthetic for surgery (Hill & Feigl, 1987).

Figure 2.C2H6 or ethane Figure 1. CH4 or methane

VOC
Hydrocarbons

Aliphatic

Aromatic

Halogenated

Oxygenated

VOC hydrocarbon categories

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Aromatic hydrocarbons are simply characterized by having an unusually
strong, stable ring of electrons as the base structure. This is typically
exemplified with benzene (C6H6) (Hill & Feigl, 1987; Godish et al.,
2014). You may recognize the compounds routinely used to produce
fuel additives for improved octane concentrations (benzene, toluene,
ethylbenzene, and xylene or the BTEX constituents) from our reading in
Unit I, or even from some of your other reading for our classes within
this program of study (Godish et al., 2014). These aromatics are the
hydrocarbons readily found in ambient air and too often considered to
be solely outdoor air quality variables. Godish et al. (2014) make it clear
in our reading for this unit that even these compounds pose a threat to
indoor air quality, given our contemporary society’s propensity for
combining various VOC types indoors from various sources to produce
concentrated polluted environments (in terms of pollutants and exposure
time) in our own homes and office dwellings. In fact, we learn that up to 40 different VOC compounds were
found to be present in residences and office buildings (Godish et al., 2014).

Halogenated hydrocarbons are some of the most readily recognized VOCs in indoor air pollution, given that
they are characterized by their quick bonding with the elements chlorine, fluorine, bromine, iodine, or astatine
(halogens) (Hill & Feigl, 1987; Godish et al., 2014). As one could readily imagine, the common use of chlorine
as a disinfectant in many residential and business (including heavy industry) environments provides a perfect
source for bonding with hydrocarbons already present in the work space or living space. The halogenated
hydrocarbons are easily formed with one hydrogen on a hydrocarbon molecule being replaced by halogen
atoms (Hill & Feigl, 1987). We can see this demonstrated with something as simple as methane being altered
in the presence of chlorine, with multiple chlorine atoms replacing the hydrogen atoms to form compounds
like the common solvent methylene chloride (CH2Cl2) or the old anesthetic (and still widely used commercial
and industrial solvent) chloroform (CHCl3). As a result, indoor air quality may be quickly polluted with the
inadvertent creation of narcotic compounds as aerosol mists and subsequent dermatitis-causing agents.
Consequently, those aerosol particles can then readily come into prolonged contact with skin with otherwise
severe irritants then becoming blood volume-altering agents with any significant prolonged contact with eyes,
mucosa, or the respiratory tract (Hill & Feigl, 1987; Godish et al., 2014; Phalen & Phalen, 2013).

Oxygenated hydrocarbons (or oxyhydrocarbons) are readily formed with a hydrocarbon in the presence of
oxygen (O2). You may recall from our first unit reading that Godish et al. (2014) demonstrate this with
methane (CH4) being exposed to O2 to create the alcohol methanol (CH3OH) also known as methyl alcohol.
Further, we are reminded of aldehydes (such as formaldehyde), ketones (such as acetone), ethers, and
organic acids (such as acetic acid) being formed and subsequently found in high concentrations in indoor air
samplings of both residential and commercial buildings (Godish et al., 2014; Phalen & Phalen, 2013). In
addition to the SVOC concentrations, Godish et al. (2014) reference many of these types of compounds as
evidenced in the findings of sick building syndrome studies from multiple Danish investigations as well as
United States investigations from the 1980s. You may recall from more recent news the health concerns and
reported sicknesses attributed to formaldehyde concentrations validated in housing provided by the U.S.
Federal Emergency Management Agency (FEMA) to flood victims of recent years.

Indoor Pollutants

Consequently, what we can expect to find in indoor air quality are pollutants that are a combination of both
anthropogenic and natural sources, often with one exacerbating the other (Godish et al., 2014). What we
need to do as environmental engineers is learn to quantify the pollutants, speciate the pollutants, and then
consider the possible sources of each pollutant as a critical step in our air quality engineering strategy. This
can be demonstrated within our practical application of this strategic approach with our course project work
for this unit.

In our course project, we are working with a scenario where you are an air quality engineering consultant
tasked with conducting an evaluation for a permit application (“Permit by Rule” or PBR) for a select painting
operation facility. We know from our work in our last unit that the Safety Data Sheets (SDS) revealed VOC
concentrations for both the paint resin coating, as well as thinners/solvents. We further know that the

Figure 3. CH2=CH2 or ethylene

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permitting state has specific guidance for quantifying VOC for air quality permitting and has provided specific
permit limits for select metrics of air quality.

We will use the following steps to calculate our VOC quantities for our air permit evaluation document.
However, for the sole purpose of demonstrating an example in this unit lesson, we will use different values
from what are provided for you in the scenario’s tabulated data. When you calculate your scenario values, use
the tabulated data presented for the scenario instead of these numbers presented in the following examples:

First, we reference our scenario for the SDS information on the coating material. Then, we multiply our
Coating Wv by the gallons of coating/unit for the interior liner coating material, to derive a value for VOC/unit.
We will not have to calculate the thinner since the thinner is pre-mixed into our coating material for this
scenario.

For example, the calculation below is for a given coating material VOC content (Coating Wv) of 4.8 lb/gal
coating and an Interior Liner Coating Material of 5 gal coating/unit (Note: The actual scenario tabulated data is
Coating Wv = 2.8 lb/gal and the Interior Liner Coating Material = 10 gal coating/unit):

VOC/unit (in lb) = Coating Wv (lb/gal coating) x Interior Liner Coating Material (gal coating/unit)

= 4.8 lb/gal x 5 gal

= 24.0 lb

Second, we reference our scenario for the SDS information on the solvent. Then, we multiply the Exempt-
solvent Content’s lb/gal by the required number of gallons of solvent/unit for the Interior Liner Coating Material
to derive a value for Exempt Solvent (ES)/unit.

For example, the calculation below is for a given Exempt-solvent Content of 1.5 lb/gal coating requiring 4 gal
solvent/unit for a given Interior Liner Coating Material (Note: The actual scenario tabulated data is Exempt-
solvent Content = 0.5 lb/gal and the Interior Liner Coating Material solvent requirement = 2 gal solvent/unit):

Exempt Solvent (ES)/unit (in lb) = Exempt-solvent Content (lb/gal) x Interior Liner Coating Material solvent
requirement (gal solvent/unit)

= 1.5 lb/gal coating x 4 gal solvent/unit

= 6.0 lb

Now, using the actual tabulated data provided for our scenario, we can calculate the actual values for our
scenario and know exactly how much VOC and ES by weight that we will need to accommodate per unit in
our operation. These calculated values will be needed when we perform our maximum hourly and annual
emission rate calculations within our next section of the air permit evaluation document. We have just
quantified the indoor air pollutants for the process, even before actually operating the booth. This type of
forecasting is how we ultimately engineer our controls to protect our indoor air quality!

References

Godish, T., Davis, W. T., & Fu, J. S. (2014). Air quality (5th ed.). Boca Raton, FL: CRC Press.

Hill, J., & Feigl, D. (1987). Chemistry and life: An introduction to general, organic, and biological life (3rd ed.).

New York, NY: Macmillian.

Phalen, R. F., & Phalen, R. N. (2013). Introduction to air pollution science: A public health perspective.

Burlington, MA: Jones & Bartlett Learning.

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Suggested Reading

In to access the following resource, click the link below.

The following article is an interesting study of the effects of longer-duration exposures to VOC concentrations
in formaldehyde-based environments (presenting an exposure to concentrated formalin levels, such as was
the instance in the post-hurricane Katrina FEMA-provided trailers mentioned in the unit lesson) on individuals’
pulmonary function (PF). This PF measurement is often a pre-employment, mid-employment, and post-
employment metric utilized to understand workers’ individual ventilation (breathing capacity) health, while
anticipating one’s exposure to indoor air quality pollutants within an industrial work system. You may
recognize the measurement as the pulmonary function test (PFT).

Uthiravelu, P., Saravanan, A., Kumar, C., & Vaithiyanandane, V. (2015). Pulmonary function test in formalin

exposed and nonexposed subjects: A comparative study. Journal of Pharmacy and Bio Allied
Sciences, 7(5), 35. Retrieved from
http://link.galegroup.com.libraryresources.columbiasouthern.edu/apps/doc/A412232583/AONE?u=ora
n95108&sid=AONE&xid=9e2f350c

http://link.galegroup.com.libraryresources.columbiasouthern.edu/apps/doc/A412232583/AONE?u=oran95108&sid=AONE&xid=9e2f350c

http://link.galegroup.com.libraryresources.columbiasouthern.edu/apps/doc/A412232583/AONE?u=oran95108&sid=AONE&xid=9e2f350c