Characterizing Formaldehyde Emissions from Home … Contract 14-303 ENERGY TECHNOLOGIES AREA ENERGY...

ENERGY TECHNOLOGIES AREA ENERGY ANALYSIS AND ENVIRONMENTAL IMPACTS D IV ISION

Characterizing Formaldehyde

Emissions from Home Central

Heating and Air Conditioning Filters

Hugo Destaillats, Marion L. Russell, William J. Fisk

Lawrence Berkeley National Laboratory

Indoor Environment Group

1

CARB Contract 14-303

E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N

Acknowledgement

Qunfang (Zoe) Zhang and Peggy Jenkins (CARB)

Toshifumi Hotchi, Brett Singer (LBNL)

Technical Advisors: Wenhao Chen, Thomas Justice, Thomas Kuehn, Drew Williams and Harinder Singh

The statements and conclusions in this report are those of the Contractor (LBNL) and not necessarily those of

the California Air Resources Board.

The mention of commercial products, their source, or their use in connection with material reported herein is not to be construed

as actual or implied endorsement of such products.

2


INTRODUCTION


We spend >90% time indoors

Indoor air: different chemical mixture than outdoor air

Higher indoor VOC concentrations (~10 to 1000 times)

Close proximity with sources in enclosed environment, leading to a higher intake than in outdoor air

Multiple pollutant sources

Indoor pollutant sources and concentrations

4

Occupant activities (smoking, cooking, cleaning)

Occupants (bioeffluents, personal care products)

Outdoor air

Building materials and furnishings


Formaldehyde is a key indoor contaminant

Carcinogen (WHO-IARC, US-EPA, CA-Proposition 65)

Irritation of eyes, respiratory system

Ubiquitous in buildings (residential > commercial)

Levels often exceed reference exposure levels (RELs)

Easy to measure – large amount of data available

Difficult to remove with most air cleaning technologies

Formaldehyde concentration (µg m-3)

0 20 40 60 80 100 120 140

100

80

60

40

20

0

Cu

mu

lati

ve f

req

uen

cy (

%)

Indoor (n=105)Outdoor (n=39)

Median indoor conc.36 µg m-3 (29 ppb)

Adapted from: Offermann, 2009 CARB/CEC Report

>95% of indoor samples above OEHHA chronic REL 9 µg m-3 (7 ppb)

25% of indoor samples above OEHHA acute REL

55 µg m-3 (43 ppb)

C

O

H H

5


What are the main indoor formaldehyde sources?

Multiple indoor sources

High emitters: materials containing urea-formaldehyde polymers

(wood products) fiberglass insulation and ceiling tiles

California regulation (ATCM 93120, 2008) established emission standards for composite wood products: hardwood plywood (HWPW), particleboard (PB), and medium density fiberboard (MDF)

France (2012): mandatory labeling of building products, based on pollutant emissions

Fiberglass HVAC filters also contain urea-formaldehyde binders

6


Hydrolytic depolymerization of urea-formaldehyde resin

7

O

N H

N

O

NH O

N H

N

HO

R1

O

HN

H

R2

H2O

O

N H

N

O

NH O

N H

N

HO

R1 HO

HN

H

R2 OH

O

N H

NH

HO

R1

+ CH2O

O

NH O

N H

N

H2N

H

R2

+ CH2O

60 oC96% RH3 months

Brown, 1990 Polymer Degradation & Stability

Degradation of UF foam insulation


Recent evidence: filters used in commercial buildings

Two unoccupied offices (Zones 1 and 2), serviced by identical HVAC units

Alternating synthetic and fiberglass filters

RH: 50% or 80% (humidifier)

Formaldehyde concentrations were higher when fiberglass filters were used, and at high relative humidity

Are fiberglass residential filtersa substantial source of formaldehyde?

8

Sidheswaran et al, 2013 Environ. Sci. Technol.

HVAC #1

Supply

Zone 2Zone 1

HVAC #2

ReturnReturn

■ Synthetic filter■ Fiberglass filter


MATERIALS AND METHODS


Selection of filters used in this study

Five experts from industry, academia and government joined Project Advisory Committee (PAC)

Input from PAC: In general, low cost MERV 7 or lower filters are resin-bonded, and use urea-

formaldehyde (UF) resin.

Formaldehyde emissions can be affected by the curing conditions of the UF resin

High-end fiberglass filter media, mostly for commercial buildings, uses phenol-formaldehyde binders

Unlikely formaldehyde sources: HEPA filters; cardboard/chipboard frame and glues; tackifier used as coating to increase particle arrestance

Criteria for filter selection: Inclusion of at least one fiberglass filter from each of the three North American

manufacturers.

Inclusion of synthetic filters from at least two manufacturers with a significant presence in the US market

Inclusion of additional fiberglass filter samples, retrieved directly from the production line of several manufacturers.

10


Filters purchased from online retailers

11

No. Manufacturer MediaMERV Rating

Description of filtration media

1 A FG na fiberglass media with light adhesive2 A FG MERV 4 fiberglass media with adhesive3 A FG MERV 4 fiberglass media with adhesive

4 B FG MERV 4fiberglass and polyester fibers

with gel adhesive5 B SYN MERV 11 synthetic filter media, pleated6 B SYN MERV 4 polyester fibers7 B SYN MERV 8 synthetic pleated filter media

8 C FG MERV 4fiberglass media,

continuous filament spun glass

9 C FG nafiberglass media,

continuous filament spun glass

10 D SYN nasynthetic media, electrostatic,

allergen reduction filter, pleated

11 D SYN MERV 8synthetic media, electrostatic,

allergen reduction filter, pleated

FG: Fiberglass SYN: synthetic


Fiberglass filters retrieved from production line

12

SampleManufacturer of

Commentsfilter media

a A AThicker fiberglass media than those typically

used for residential buildings.

b A AThicker fiberglass media than those typically

used for residential buildings.c C X Relatively recent productiond C X Relatively recent productione A A Sample is at least 5 years oldf C Z Relatively recent productiong C Z Relatively recent productionh C Z Relatively recent production

i Unknown Unknown Imported from China


Experimental setup used in bench-scale tests

13

Tested filters

Upstream sampling port

Downstream sampling port

Vent

Logging system

Heating plate

Upstream air internal inlet

Teflon tubingDownstream air internal outlet

MFC

MFC

House air

HEPA filter

Activated carbon filter

Water bubbler

T, RH sensors

200–L chamber


Bench-scale test chamber

14

Air flows from

bottom to top

Air outlet Air inletSampling

ports


Experimental setup used in room-sized chamber tests

15

Humidifier #3

Upstream sampling port

Chamber exhaust

Logging system

Outdoor air

Activated carbon + chemisorbent bed

T, RH, CO2

sensors

20–m3 chamber

Custom-made filter

holder

Downstream sampling port

Humidifier #1

Humidifier #2

RH controller

Fan

Recirculation loop

Variable speed fan

Iris damper

Flexible ductwork (ending opposite side of chamber)


Exterior view of room-sized chamber

16

20-m3 chamber

upstream

Sampling ports

Variable-speed fan

Custom-built filter holder

Iris damper

downstream


Interior view of room-sized chamber

17

From external loop

Three home humidifiers

Fan

To external loop

Humidity Controller

door

From external loop

Three home humidifiers

Fan

To external loop

Humidity Controller

door


Formaldehyde sampling and analysis

Method EPA TO-11A (1999)

Sampling

collection using dinitrophenyl hydrazine (DNPH)-coated silica samplers (Waters)

simultaneous upstream/downstream sampling

flow: 1 L min-1 ± 1% over 1 hour for V = 6 L

Analysis

Samplers were extracted with 2 mL acetonitrile

Analyzed by HPLC with UV detection at 360 nm

Calibration curve using authentic standards of the corresponding DNPH hydrazone derivative

Limit of detection < 0.1 μg m-3

18

[H+] - H2O

+


RESULTS


0 0

182

99

165

84

166

92

0

40

80

120

160

200

24 h 48 h

ΔC

(p

pb

) chamber blankFG - sample cFG - sample dFG - sample g

0 0

122 119

5139

2821

42 38

3.7 2.84.0 3.00

20

40

60

80

100

120

140

24 h 48 h

ΔC

(p

pb

)

chamber blank

FG - sample 3 (A)

FG - sample 9 (C)

FG - sample 4 (B)

FG - sample 1 (A)

SYN - sample 11 (D)

SYN - sample 5 (B)

Formaldehyde concentration in bench-scale chamber

20

blank blank

blank blank

Fiberglass and synthetic

filters purchased

from retailers

Fiberglass filters from production

line

RH = 62 – 64 %

RH = 62 – 64 %


Relative change from 24-h to 48-h sample (63% RH)

21

Fiberglass and synthetic

filters purchased

from retailers

Fiberglass filters from production

line

2.5

24 24

9

2326

0

5

10

15

20

25

30

Dec

reas

ed b

etw

een

2

4h

an

d 4

8h

sam

ple

(%

)

FG - sample 3 (A)

FG - sample 9 (C)

FG - sample 4 (B)

FG - sample 1 (A)

SYN - sample 11 (D)

SYN - sample 5 (B)

4649

45

0

10

20

30

40

50

60

Dec

reas

ed b

etw

een

2

4h

an

d 4

8h

sam

ple

(%

)

FG - sample c

FG - sample d

FG - sample g


122

98

1633

119

84

30

0

20

40

60

80

100

120

140

64% (Jul '15) 64% (Jan '16) 16% (Jan '16) 34% (Jan '16)

ΔC

(pp

b)

Average Relative Humidity

Filter 3 (A)

24 h

48 h

51

14

4.2

39

13

3.6

0

10

20

30

40

50

60

63% (Ago '15) 62% (Feb '16) 33% (Feb '16)

ΔC

(p

pb

)


Filter 9 (C)

24 h

48 h

Effects of filter aging and relative humidity

22

Some FG filters emitted lower formaldehyde after 6 month storage

All FG filters emitted significantly less formaldehyde when RH was reduced from 62-64% to 32-34%

20 – 30 % loss

65 – 75 % loss2830

8.2

21

26

5.3

0

5

10

15

20

25

30

35

62% (Aug '15) 64% (Mar '16) 32% (Mar '16)

ΔC

(pp

b)


Filter 4 (B)

24 h

48 h

64% (Jul ‘15) 64% (Jan ‘16) 16% (Jan ’16) 34% (Jan ‘16)


62% (Aug ‘15) 64% (Mar ‘16) 32% (Mar ‘16)


65 % lower

63% (Aug ‘15) 62% (Feb ‘16) 32% (Feb ‘16)


70 % lower70 – 80 % lower


98

46

34

84

47 44

0

10

20

30

40

50

60

70

80

90

100

Full filter Media only Frame only

ΔC

(p

pb

)

Filter 3 (A)

24 h

48 h

Filter media vs. frame: both were comparable sources

23

47 – 56 % 35 – 53 %

34 – 38 % 35 – 40 % 79 – 85 % 58 – 60 %

Roughly equal amounts of formaldehyde were emitted from the media and the frame

When compared with full filter, approximate mass balance was reached

30

10.2 12

26

9.9 9.0

0

5

10

15

20

25

30

35


ΔC

(pp

b)

Filter 4 (B)

24 h

48 h

14

11

8.4

1311

7.6

0

2

4

6

8

10

12

14

16


ΔC

(p

pb

)

Filter 9 (C)

24 h

48 h

Full filter Media only Frame only Full filter Media only Frame only



Formaldehyde concentration in room-sized chamber

24

Striped bars: 400 cfm

(face velocity 0.5 m s-1)

Solid bars:

1000 cfm

(face velocity 1.3 m s-1)

4.03.6 3.5 3.6

4.03.4

4.1

4.8

6.76.3

6.67.1

3.3

4.0

5.0

3.7

0

1

2

3

4

5

6

7

8

Co

nce

ntr

atio

n (

pp

b)

36 - 46 % RH

FG - sample 3 (A) FG - sample 4 (B) FG - sample 9 (C)

chamber background

SYN - sample 11 (D)

24 2623 23

1316

2023 24

30

51 52

6.8 5.5 6.8 6.8

0

10

20

30

40

50

60

Co

nce

ntr

atio

n (

pp

b)

68 - 72 % RH

chamber background

FG - sample 3 (A) FG - sample 4 (B) FG - sample 9 (C) SYN - sample 11 (D)

24


Additional measurements were needed for two FG filters

25

1316

2023

18

30

0

5

10

15

20

25

30

35

Co

nce

ntr

atio

n (

pp

b)

FG - sample 4 (B), 69 - 72 % RH

original data additional results

chamber background

2430

51 52

26

46

70

62

51 50

0

10

20

30

40

50

60

70

80

Co

nce

ntr

atio

n (

pp

b)

FG - sample 9 (C), 69 - 72 % RH

original data additional results

chamber background


Formaldehyde emission rates at moderate RH

FG: 60 – 300 µg h-1 m-2

SYN: 60 – 180 µg h-1 m-2

26

90 75 87 920

50

100

150

200

E F(µ

g h

-1m

-2)

FG - sample 3 (A)

400 cfm 1000 cfm

86 62 114 1560

50

100

150

200

E F(µ

g h

-1m

-2)

FG - sample 4 (B)

400 cfm 1000 cfm

213 191 266 2960

100

200

300

400

E F(µ

g h

-1m

-2)

FG - sample 9 (C)

400 cfm 1000 cfm

60 98 185 1020

50

100

150

200

250

E F(µ

g h

-1m

-2)

SYN - sample 11 (D)

400 cfm 1000 cfm

EF =ΔC x Vchamber x λchamber

Afilter

Room-sized chamber

Vchamber = chamber volumeλchamber = chamber air exchange rateAfilter = area of filter


Formaldehyde emission rates at high RH

FG: 500 – 4000 µg h-1 m-2

SYN: 100 – 220 µg h-1 m-2

27

993 1054 1153 11520

500

1000

1500

E F(µ

g h

-1m

-2)

FG - sample 3 (A)

400 cfm 1000 cfm

456 587 958 1099 862 15240

500

1000

1500

2000

E F(µ

g h

-1m

-2)

FG - sample 4 (B)

400 cfm 1000 cfm

990 1264 2915 2976 1346 2528 3914 3449 2891 28240

1000

2000

3000

4000

5000

E F(µ

g h

-1m

-2)

FG - sample 9 (C)

400 cfm 1000 cfm

165 102 223 2210

50

100

150

200

250

300

E F(µ

g h

-1m

-2)

SYN - sample 11 (D)

400 cfm 1000 cfm


DISCUSSION


How do our results compare with others?

29

0.1

1

10

100

1000

10000

100000

BUF CUF PP DL FG BPF P LowRH

HighRH

LowRH

HighRH

FG -LowRH

FG -HighRH

SYN -HighRH

FG -LowRH

FG -HighRH

SYN -HighRH

Form

ald

ehyd

e em

issi

on

rat

e (µ

g m

-2h

-1)

Kelly et al, 1999 - ES&TSidheswaran

et al, 2013 - ES&T

Low face velocity

High face velocity

This work

Low face velocity

(bench scale)

High face velocity

(room scale)

Various building materialstested at 50 % RH

FG HVAC filters for commercial buildings

HVAC filters for residential buildings

Bar

e U

F w

oo

d p

rod

s.

Fab

rics

Co

ated

UF

wo

od

pro

ds.

Lam

inat

es

Bar

e P

F p

rod

s.

Pap

er

FG p

rod

s.


Impact of FG filters was predicted in three scenarios

HOME ARB 1 ARB 2 ARB 3

74 m2 (800 ft2) apartment

140 m2 (1500 ft2) house

325 m2 (3500 ft2)2-story house

Indoor space volume (m3)

182 343 796

Filter(s) used 12“ x 24” 18” x 24” 24” x 24”12” x 24”24” x 24”

Two24” x 24”

Three24” x 24”

Total filter surface area (m2)

0.18 0.27 0.36 0.54 0.72 1.08

Φ (x 10-3) 2.4 3.6 2.6 3.9 2.4 3.6

area floor home

area surfacefilter ΔC =

EF x Afilter

Vhome x λhome

Vhome = indoor space volumeλhome = home air exchange rate

30


Contribution to indoor formaldehyde (24/7 operation)

31

RH = 40% ; λ= 0.2 h-1

ARB 1

Lower Φ

RH = 70% ; λ= 0.2 h-1 RH = 70% ; λ= 0.5 h-1

ARB 1

Higher Φ

ARB 2

Higher Φ

RH = 40% ; λ= 0.2 h-1 RH = 70% ; λ= 0.2 h-1 RH = 70% ; λ= 0.5 h-1

RH = 40% ; λ= 0.2 h-1 RH = 70% ; λ= 0.2 h-1 RH = 70% ; λ= 0.5 h-1


Some building designs require HVAC continuous operation for mechanical ventilation/particle filtration

In all other (most) cases, HVAC systems follow duty cycles

Model to calculate the fraction of time during which HVAC system operates adaptedfrom Logue et al (2012).

Based on linear correlationof time fraction andΔT between outdoor air and thermostat setting:

Heating: 18 oC (65 F)

Cooling: 26 oC (78 F)

32

Establishing the HVAC duty cycle for different climates

new homes

old homes

average


Eight representative CA climate zones were evaluated

33

San Francisco(CZ 3)

Los Angeles (CZ 6)

Stockton(CZ 12)

Riverside(CZ 10)

Fresno(CZ 13)

Browley(CZ 15)

Bishop(CZ 16)

Eureka(CZ 1)

Warmest summers

Coldest winters


Climate zone 16: Bishop

34

DUTYCYCLE

Heating (January)

Cooling (July)

Min T 67% -

Average T 37% 4%

Max T 10% 66%

Source: PG&E Guide to California Climate Zones - 2017 https://www.pge.com/myhome/edusafety/workshopstraining/pec/toolbox/arch/climate/index.shtml


Predicted time fraction for HVAC operation

35

CA climate

zoneCity

Heating season Cooling season

MonthTemp. (oC)

Hourly time fractional Month

Temp. (oC)Hourly time

fractional

min mean min mean mean max mean max

1 Eureka JAN 5.0 8.9 41% 26% SEP 13.3 16.7 8%*

3 SF JAN 6.1 8.9 37% 26% SEP 17.8 22.8 8%

6 LA JAN 7.8 12.8 30% 10% AUG 20.5 24.4 15%

10 Riverside JAN 4.4 11.7 44% 15% JUL 20.0 34.4 55%

12 Stockton JAN 2.8 7.2 50% 32% JUL 24.4 35.0 15% 57%

13 Fresno JAN 2.8 7.8 50% 30% JUL 27.2 36.7 26% 63%

15 Browley JAN 3.9 12.8 50% 14% JUL 32.8 42.2 39% 77%

16 Bishop JAN - 6.7 3.3 67% 37% JUL 24.4 36.7 4% 66%

* due to heating during the summer


Outdoor air is unlikely to generate high indoor RH

Winter: very high outdoor RH (at low T) correspond to moderate contributions to indoor RH (only 15 – 40 % RH)

Summer: moisture in outdoor air condenses at the AC unit; liquid water is drained out of the system

Indoor moisture sources play a very important role

36

Sources of indoor moisture

Activity EH2O (L day-1)

5-min shower (x4) 1.0Cooking on gas range 2.4Dishwashing 0.5Floor mopping 3.0House plants 0.4Respiration / perspiration 5.0TOTAL 12.3

HomeAir exchange

rate (h-1)RH (%)

@ 65 F @ 78 F

ARB 10.2 80 500.5 32 20

ARB 20.2 45 250.5 18 10

ARB 30.2 20 100.5 8 4

Contribution of residential moisture sources

estimated for a family of four members

(adapted from Trechsel et al, 1994)

Indoor relative humidity from residential moisture

sources, neglecting contributions from outdoor

air and moisture removal by different sinks


High outdoor RH does not translate into high indoor RH

37

Fresno, Stockton

Riverside

Bishop

Browley

Los Angeles, San Francisco

70% RH 40% RH

Eureka

Psychrometric chart

January


Family of four

ARB 1 home; λ = 0.2 h-1; winter thermostat setting (18 oC, 65 F)

Duty cycle corresponding to January in each climate zone

Considering only indoor moisture sources, no sinks

Values correspond to emission rates from all tested FG filters

38

Predicted indoor formaldehyde concentrations (i/ii)

9.3

1.1

8.1

0.94

7.6

0.88

6.4

0.75

6.4

0.75

3.7

0.43

3.6

0.41

2.6

0.30

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

Bishop (37%) Stockton (32%) Fresno (30%) Eureka (26%) San Francisco(26%)

Riverside (15%) Browley (14%) Los Angeles(10%)

Δ[F

orm

ald

eh

yde

] (

pp

b)

Prop 65 NSRL

OEHHA Chronic REL

Worst-case scenario OEHHA Chronic REL

Prop 65 NSRL


39

Predicted indoor formaldehyde concentrations (ii/ii)

0.70

0.15

0.62

0.13

0.57

0.12

0.49

0.10

0.49

0.10

0.28

0.06

0.27

0.06

0.19

0.04

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

Bishop (37%) Stockton (32%) Fresno (30%) Eureka (26%) San Francisco(26%)

Riverside (15%) Browley (14%) Los Angeles(10%)

Δ[F

orm

ald

ehyd

e] (

pp

b)

Family of four

ARB 2 home; λ = 0.2 h-1; winter thermostat setting (18 oC, 65 F)

Duty cycle corresponding to January in each climate zone

Considering only indoor moisture sources, no sinks

Values correspond to emission rates from all tested FG filters

Typical scenario


CONCLUSIONS

AND PERSPECTIVES


Residential FG filters emit formaldehyde in contact with humidified air (>> synthetic filters) Consistent w/ previous results in commercial buildings

Emissions were observed from media AND frame

In most cases, FG filters can increase indoor formaldehyde concentrations by only a few ppb

Emissions can impact IAQ more severely in a subset of conditions (high occupancy, low air exchange rate, smaller spaces, extreme weather, varying by location) Exceeding OEHHA Chronic REL in three areas simulated

Source-control strategies may include: Replacing urea-formaldehyde polymers used as binders for FG

Replacing FG filters by other low-emitting filters

Both solutions may be limited by cost barriers

Summary of findings

41


A limited set of experimental conditions was evaluated (number and types of filters, face velocity, etc)

Only two indoor RH settings were considered: moderate (35 -45%) and high (62 -72%).

Eight climate zones were considered, comprising most of the State’s population. Effects could be more severe in other parts of the USA with more extreme climates.

Tests were carried out over short periods of time (initial conditions) using clean laboratory air. What about longer exposure periods?

Study was carried out using only unexposed filters… what about used filters? What is the effect of “filter cake”?

Limitations of the study

42


Hints from a previous study…

“Filter cake” can contribute to additional formaldehyde emissions, by:

Serving as a moisture reservoir in direct contact with the fiberglass media, and/or

Becoming another formaldehyde source

43

Formaldehyde concentration measured downstream of FG filter @ 50% RH.

• LBNL: 3 month of use in an LBNL building (outdoor particles mostly influenced by vegetation)

• POAK: 3 months of use at the Port of Oakland (outdoor particle mostly diesel emissions, freeway traffic).

Destaillats et al, 2011 – Atmos. Environ.


Literature citedDestaillats, H., W. Chen, M. G. Apte, N. Li, M. Spears, J. Almosni, G. Brunner, J. Zhang and W. J. Fisk. 2011. "Secondary pollutants from ozone reactions with ventilation filters and degradation of filter media additives." Atmos. Environ. 45: 3561-3568.

Kelly, T. J., D. L. Smith and J. Satola. 1999. "Emission rates of formaldehyde from materials and consumer products found in California homes." Environ. Sci. Technol. 33: 81-88.

Logue, J.M., W.J.N. Turner, I.S. Walker, B.C. Singer. 2012. "Evaluation of an incremental ventilation energy model for estimating impacts of air sealing and mechanical ventilation". LBNL Report 5796E. https://indoor.lbl.gov/publications/evaluation-incremental-ventilation

Offermann, F. J. 2009. "Ventilation and Indoor Air Quality in New Homes. ." California Air Resources Board and California Energy Commission, PIER Energy‐Related Environmental Research Program. Collaborative Report. CEC‐500‐2009‐085. http://www.arb.ca.gov/research/apr/past/04-310.pdf.

Sidheswaran, M., W. Chen, A. Chang, R. Miller, S. Cohn, D. Sullivan, W. J. Fisk, K. Kumagai and H. Destaillats. 2013. "Formaldehyde emissions from ventilation filters under different relative humidity conditions." Environ. Sci. Technol. 47: 5336-5343.

Trechsel, H.R., Editor. 1994. "Moisture Control in Buildings". ASTM Manual Series: MNL 18, American Society for Testing and Materials, Philadelphia, PA

US EPA. 1999. "Compendium Method TO-11ADetermination of Formaldehyde in Ambient Air Using Adsorbent Cartridge Followed by HPLC [Active Sampling Methodology]". Office of Research and Development, U.S. Environmental Protection Agency (U.S. EPA): Cincinnati, OH, 1999.

44

Thanks!

Date post:	15-May-2018
Category:	Documents
Upload:	lykien
View:	215 times
Download:	2 times

Characterizing Formaldehyde Emissions from Home … Contract 14-303 ENERGY TECHNOLOGIES AREA ENERGY...

Documents