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Contaminants in hotel room exhaust air.

INTRODUCTION

Large hotels are a specifically intriguing case because the air volumes exhausted can be large. The guest rooms remain unoccupied for large portions of time, causing the air exhausted from toilet areas to be essentially free of people generated contamination. In many cases, the hotel design requires this tempered and dehumidified air to be continuously thrown away to the outdoors in order to keep building pressure relationships and airflows under control. "Recycling" a portion of the exhaust air through an air filtration system (both gas-phase and particulate) allows hotels to "recycle" the energy used to originally condition that exhaust air.

Although the concept is not new, the idea of "recycling" exhaust air is understandably viewed skeptically. There is an unknown, i.e. what contaminants are in the exhaust air. On the other hand, hotels exist which have used an "air recycling" strategy through air cleaning for several decades and enjoyed both acceptable air quality and comparably low HVAC energy costs. Understanding the contaminants in the hotel guest room exhaust air will allow engineers and indoor air quality professionals to make better informed decisions related to energy savings through "air recycling".

AIR SAMPLING METHODOLOGY

Contaminants

The authors desired to sample for airborne contaminants that would represent the areas of concern for indoor air quality. The areas of concern included building product and furnishing emissions, people generated contaminants (bioeffluents and contaminants generated from various activities), and contaminants perceived to be specifically associated with toilet room exhaust. There was no characterization for environmental tobacco smoke as this was a nonsmoking facility. The list of contaminants and analytical methods is shown below. The volatile organic compound sampling and analysis method targeted 75 chemical compounds commonly found in indoor air representing both building material and furnishing emissions and people generated contaminants. The aldehyde sampling and analysis method targeted 8 aldehydes representing building material and furnishing emissions and, to a lower degree, people generated contaminants. Ammonia and hydrogen sulfide represented bioeffluents and sewer system contaminants. The bioaerosols were of particular interest because of the perception that their concentrations may be elevated in potentially elevated moisture locations such as toilet (or shower) exhaust air.

1. Airborne Chemicals

a. Volatile Organic Compounds (speciated EPA method TO-15)

b. Aldehydes (EPA method TO-11A)

i. acetaldehyde, benzaldehyde, butyraldehyde, formaldehyde, isovaleraldehyde, n-hexaldehyde, propionaldehyde, valeraldehyde

c. Ammonia (OSHA ID-188/ID-164)

d. Hydrogen Sulfide (CAS AQL 110 using spectrophotometer)

2. Bioaerosols

a. Non-Viable and Viable Fungi (Spore Trap Active Impaction and SAS Sampler with Anderson Style Active Plate Impaction)

b. Bacteria (SAS Sampler with Anderson Style Active Plate Impaction). A two plate protocol was used to select out gram-negative rods, such as E. coli, coliforms or non-fermenters (Pseudomonas species).

Sampling Time Period and Method

For all contaminants, the authors desired to use extended sampling times to allow for detection of lower concentrations as well as to capture events that may be missed in short grab sample type sampling. As much as possible, the sampling period began on the afternoon of one day and lasted through the night until the afternoon of the following day. The purpose was to catch nighttime activities of hotel guests who are not present during the day. Samples were taken two times in the spring about one month apart. This paper contains the results from the second sample date. Table 1 shows the approximate sample periods and medium used for each contaminant type.
Table 1. Sampling Time Periods and Medium for Each Contaminant Type

Contaminant       Example         Sampling Medium
                  Sampling
                   Period

volatile organic  24hrs     Summa Canister w/ flow
compounds                   controller

aldehydes         24hrs     Passive Radiello DNHP tubes
                            (code 165)

ammonia           4 hrs     Sulfuric Acid-Coated
                            Anasorb-747 (carbon bead)
                            tubes

hydrogen sulfide  24hrs     Passive Radiello tubes (code
                            170)


Location and Sampling Setup

Figure 1 shows the sampling location within the plenum of the exhaust air handling unit. The hotel has all toilet exhaust risers ducted to a common air handler location that feeds the air filtration system and discharges to the hotel atrium. The samples were taken upstream of the air filtration system taking care to place the sampling medium as close to the center of the airstream as possible.

RESULTS

Tables 2 through 7 show the airborne contaminant concentrations. Table 2 displays the volatile organic compound results; only 27 of the 75 compounds were above the method detection limits. Table 3 contains the aldehyde results, indicating the presence of three aldehydes: acetaldehyde, formaldehyde, and n-hexaldehyde. Table 4 puts forth the ammonia and hydrogen sulfide results, both were below detection limits. Table 5 presents the non-viable fungi (spores) results indicating the presence of basidiospores, botrytis, Cladosporium, hyphal elements, and Penicillium/Aspergillus type spores. Table 6 shows the viable fungi results indicating the presences of Acremonium sp., Cladosporium sp., non-sporulating colonies, Penicillium sp., and Rhodotorula sp. Table 7 displays the bacteria results indicating the presence of coag-negative Staphylococcus sp. and Micrococcus sp. No samples contained escherichia coli bacterium.
Table 2. Volatile Organic Compound Air Sampling Results

Volatile Organic Compound *  CAS #
                                              Result
                                          ([mu]g/[m.sup.3])

1,4-dichlorobenzene          106-46-7                0.2

2-propanol (isopropyl        67-63-0                  25

alcohol)
acetone                      67-64-1                  49

acetonitrile                 75-05-8                   2

alpha-pinene                 80-56-8                 2.6

benzene                      71-43-2                0.85

bromodichloromethane         75-27-4                0.95

carbon tetrachloride         56-23-5                0.48

chloroform                   67-66-3                 6.6

chloromethane                74-87-3                0.44

dichlorodifluoromethane      75-71-8                 2.6

(cfc 12)

d-limonene                   5989-27-5                11

ethanol                      64-17-5                 980

ethyl acetate                141-78-6                5.6

ethylbenzene                 100-41-4                2.3

m,p-xylenes                  179601-23-1             6.1

n-butyl acetate              123-86-4                2.4

n-heptane                    142-82-5                1.1

n-hexane                     110-54-3                1.2

n-octane                     111-65-9               0.92

o-xylene                     95-47-6                 1.2

propene                      115-07-1                8.3

tetrachloroethene            127-18-4                5.4

toluene                      108-88-3                6.2

trichloroethene              79-01-6                0.49

trichlorofiuoromethane       75-69-4                 1.3

trichlorotrifluoroethane     76-13-1                0.48

Volatile Organic Compound *  CAS #            Plenum
                                                MRL
                                          ([mu]g/[m.sup.3])

1,4-dichlorobenzene          106-46-7               0.15

2-propanol (isopropyl        67-63-0                 1.5
alcohol)

acetone                      67-64-1                 7.7

acetonitrile                 75-05-8                0.77

alpha-pinene                 80-56-8                0.77

benzene                      71-43-2                0.15

bromodichloromethane         75-27-4                0.15

carbon tetrachloride         56-23-5                0.15

chloroform                   67-66-3                0.15

chloromethane                74-87-3                0.31

dichlorodifluoromethane      75-71-8                0.77

(cfc 12)

d-limonene                   5989-27-5              0.77

ethanol                      64-17-5                  39

ethyl acetate                141-78-6               0.77

ethylbenzene                 100-41-4               0.77
m,p-xylenes                  179601-23-1            0.77

n-butyl acetate              123-86-4               0.77

n-heptane                    142-82-5               0.77

n-hexane                     110-54-3               0.77

n-octane                     111-65-9               0.77

o-xylene                     95-47-6                0.77

propene                      115-07-1               0.77

tetrachloroethene            127-18-4               0.15

toluene                      108-88-3               0.77

trichloroethene              79-01-6                0.15

trichlorofiuoromethane       75-69-4                0.15

trichlorotrifluoroethane     76-13-1                0.15

Volatile Organic Compound *  CAS #        Concentration

                                              Result         MRL
                                              (ppbv)       (ppbv)

1,4-dichlorobenzene          106-46-7             0.034   0.026

2-propanol (isopropyl        67-63-0                 10    0.63
alcohol)

acetone                      67-64-1                 20     3.2

acetonitrile                 75-05-8                1.2    0.46

alpha-pinene                 80-56-8               0.46    0.14

benzene                      71-43-2               0.27   0.048

bromodichloromethane         75-27-4               0.14   0.023

carbon tetrachloride         56-23-5              0.077   0.024

chloroform                   67-66-3                1.4   0.032

chloromethane                74-87-3               0.21    0.15

dichlorodifluoromethane      75-71-8               0.53    0.16

(cfc 12)

d-limonene                   5989-27-5                2    0.14

ethanol                      64-17-5                520      20

ethyl acetate                141-78-6               1.5    0.21

ethylbenzene                 100-41-4              0.52    0.18

m,p-xylenes                  179601-23-1            1.4    0.18

n-butyl acetate              123-86-4              0.51    0.16

n-heptane                    142-82-5              0.27    0.19

n-hexane                     110-54-3              0.33    0.22

n-octane                     111-65-9               0.2    0.16

o-xylene                     95-47-6               0.28    0.18

propene                      115-07-1               4.8    0.45

tetrachloroethene            127-18-4               0.8   0.023

toluene                      108-88-3               1.6     0.2

trichloroethene              79-01-6              0.092   0.029

trichlorofiuoromethane       75-69-4               0.23   0.027

trichlorotrifluoroethane     76-13-1              0.063    0.02

* Method evaluated the presence or 75 total volatile organic
compounds. There are only 27 compounds indicated above. All
others compounds were below the method reporting limit.

Table 3. Aldehyde Air Sampling Results

Aldehyde            CAS#                               Plenum
                                                   Concentration

                                    Result                MRL
                              ([mu]g/[m.sup.3])  ([mu]g/[m.sup.3])

acetaldehyde        75-07-0                18.0                1.7

formaldehyde        50-00-0                28.0                1.4

n-hexaldehyde       66-25-1                15.0                7.7

benzaldehyde +      100-52-7                  -                  -

butyraldehyde +     123-72-8                  -                  -

Isovaleraldehyde +  590-86-3                  -                  -

Propionaldehyde +   123-38-6                  -                  -

valeraldehyde +     110-62-3                  -                  -

Aldehyde            CAS#

                              Result    MRL
                              (ppbv)  (PPbv)

acetaldehyde        75-07-0      9.8     0.9

formaldehyde        50-00-0     23.0     1.1

n-hexaldehyde       66-25-1      3.6     1.9

benzaldehyde +      100-52-7       -       -

butyraldehyde +     123-72-8       -       -

Isovaleraldehyde +  590-86-3       -       -

Propionaldehyde +   123-38-6       -       -

valeraldehyde +     110-62-3       -       -

+ These aldehydes were monitored approximately one month before at the
same sampling location and found to be below the method reporting
limit. Therefore, the analytical method was revised to exclude these
from this air sampling visit.

Table 4. Ammonia and Hydrogen Sulfide Air Sampling Results

Compound  CAS #                        Plenum Concentration
                       Result[yen]      MRL (mg/[m.sup.3],
                      (mg/[m.sup.3],     [mu]g/[m.sup.3])
                     [mu]g/[m.sup.3])

ammonia   7664-41-7                ND                 0.087

hydrogen  7783-06-4                ND                   2.6

sulfide

Compound  CAS #

                      Reslt[yen]   MRL (ppmv,
                     (ppmv, ppbv)    ppbv)

ammonia   7664-41-7            ND        0.12

hydrogen  7783-06-4            ND         3.6

sulfide
[yen] Concentrations for ammonia are in mg/m3 and ppmv. Concentrations
for hydrogen sulfide are in g/[m.sup.3] and ppbv.
ND = nondetect.

Table 5. Non-Viable Fungi (Spore) Air Sampling Results

Spore Identifier             Plenum Concentration
                             (Spores/[m.sup.3])
                                         Sample 1  Duplicate
                                                      Sample

algae                                           -          -

Alternaria                                      -          -

ascospores                                     75        225

basidiospores                                 633        633

Botrytis                                        -          -

Cercospora                                      -          -

Cladosporium                                   83        142

clear brown                                     -          -

Curvularia                                      -          -

Curvularia-Xike                                 -          -

Dechslera/Bipolaris group                       -          -

Epicoccum                                       -          -

Helicosporium / Helicomyces                     -          -

hyphal elements                                 8          -

Monochaetia                                     -          -

Nigrospora                                      -          -

Oidium                                          -          -

Penicillium/Aspergillus                       150         83

group

Peronospora                                     -          -

smuts, Periconia,                               -          -

myxomycetes

Torula                                          -          -

unknown                                         -          -

Total                                         949       1083

Table 6. Viable Fungi Air Sampling Results
Viable Fungi Identifier  Plenum Concentration

                           (CFU/[m.sup.3])
                               Sample 1        Duplicate
                                                 Sample

Acremonium species                          -          6

Alternaria species                          -          -

arthrospore former                          -          -

Aspergillus niger                           -          -

Aspergillus species                         -          -

Aureobasidium species                       -          -

Cladosporium species                       22         39

Epicoccum species                           -          -

Fusarium species                            -          -

non-sporulating                             6          -

colonies

Olpitrichum species                         -          -

Paecilomyces species                        -          -

Penicillium species                        11          -

(mixed)

Rhodotorula species                         -          6

yeast                                       -          -

Total                                      39         51


Table 7. Bacteria Air Sampling Results
 bacteria identifier    plenum concentration

                             (cfu/[m.sup.3])
                                 sample 1        duplicate
                                                   sample

Bacillus species                            -          -

coag-negative                              22          -

Staphylococcus species

Corynebacterium species                     -          -

Micrococcus species                        22         22

non-fermentative gram                       -          -

negative rod

Streptomyces species                        -          -

Total                                      44         22

Note: The presence of Escherichia coli bacteria not present in any of
the samples collected was


CONCLUSION

There currently exists little data on the environmental characterization of hotel room toilet exhaust. Tables 2 through 7 characterize a collective hotel room toilet exhaust airstream over a 24 hour period in terms of airborne chemical presence, non-viable and viable fungi presence, and bacteria presence. This data can help engineers, building owners, and indoor air quality professionals become familiar with the types of contaminants and the range of concentrations that may be present in such airstreams to assist with designs for recirculation of similar exhaust air types.

ACKNOWLEDGMENTS

The authors would like to thank Aflal Rahmathullah and Rob Schick for their assistance in gathering this data.

Brad Stanley is the Gas-Phase Global Technical Support Leader AAF and currently serves as Vice Chair for ASHRAE TC2.3. Bryan Ligman is the IAQ Technical Market Manager for AAF Americas and a Council-certified Indoor Environmental Consultant (CIEC).

REFERENCES

ASHRAE. (2010). ANSI/ASHRAE Standard 62.1-2010 Ventilation for Acceptable Indoor Air Quality. Atlanta, GA: American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.

Columbia Analytical Services. Air Quality Lab Method 110 (CAS AQL 110). Simi Valley, CA.

U.S. Environmental Protection Agency. (1999). Method TO-15: Determination of Volatile Organic Compounds (VOCs) In Air Collected In Specially-Prepared Canisters And Analyzed By Gas Chromatography/Mass Spectrometry (GC/MS) (EPA/625/R-96/010b). Cincinnati, OH: Center for Environmental Research Information, Office of Research and Development.

U.S. Environmental Protection Agency. (1999). Method TO-11A: Determination of Formaldehyde in Ambient Air Using Adsorbent Cartridge Followed by High Performance Liquid Chromatography (HPLC) [Active Sampling Methodology]. Cincinnati, OH: Center for Environmental Research Information, Office of Research and Development.

U.S. Occupational Safety & Health Administration. (2002). Method ID-188: Ammonia in Workplace Atmospheres - Solid Sorbent. Sandy, UT: Methods Development Team, Industrial Hygiene Chemistry Division.

W. Brad M. Stanley

Associate Member ASHRAE

Bryan K. Ligman

Member ASHRAE

Brad Stanley is the Gas-Phase Global Technical Support Leader AAF and currently serves as Vice Chair for ASHRAE TC2.3. Bryan Ligman is the IAQ Technical Market Manager for AAF Americas and a Council-certified Indoor Environmental Consultant (CIEC).
COPYRIGHT 2012 American Society of Heating, Refrigerating, and Air-Conditioning Engineers, Inc.
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Author:Stanley, W. Brad M.; Ligman, Bryan K.
Publication:ASHRAE Transactions
Article Type:Report
Geographic Code:1USA
Date:Jul 1, 2012
Words:2000
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