Contaminant build-up in houses

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Contaminant build-up in houses

Manley, P. J.; Helmeste, R. H.; Tamura, G. T.

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Ser I

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CONTAMINANT BUILD-UP IN HOUSES

by P.J. Manley, R.H. Helmeste, and G.T. Tamura

ANALYZED

Presented at

The Implementation and Effectiveness of Air l nfiltration Standards in Buildings

5th AIC Conference, October 1

-

4

1984, Reno, Nevada, USA Paper 19, p. 19.1

-

19.12

6

DBR Paper No. 1277

Division of BuHding Research

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I

ABSTRACT

The relation between air infiltration rate and indoor air

contaminant concentrations has been investigated in a number of

air-conditioned Toronto houses with low rates of natural

ventilation whose average values were lower in summer than in

winter.

The average indoor formaldehyde, radon and radon

daughter concentrations conversely, were found to be higher in

summer than in winter.

R ~ S U M ~

La relation entre le d6bit dlinfiltration de llair et les

concentrations de polluants 21

11int6rieur dlun certain nombre

de maisons climatisdes de Toronto a fait llobjet dlune 6tude.

Ces maisons pr6sentaient de faibles taux de ventilation

naturelle dont les valeurs moyennes Qtaient plus Qlev6es en

hiver qu'en 6t6. Les concentrations moyennes de formald6hyde,

de radon et des gaz de la famille du radon

3 11int6rieur des

maisons 6taient plus dlev6es durant 116t6

que durant llhiver.

- -

__

- _- _- - -- 3 cp'lc"

1 I

1111

I I I I I ~ ~ I [ ~ ~

O

~!(r

0 4 8

n 111111

1111

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THE

IMPLEMENTATION

AND

EFFECTIVENESS

OF A I R

INFILTRATION STANDARDS IN BUILDINGS

5 t h

AIC

Conference,

October 1-4 1984,

Reno,

Nevada, USA

PAPER

19

CONTAMINANT BUILD-UP I N HOUSES

P.J. MANL,EY,l R.H. H E L M E S T E , ~ AND G.T. TAMURA~

lP.J. Manley i s a S e n i o r P r o j e c t Manager w i t h t h e c o n s u l t i n g f i r m of MacLaren E n g i n e e r s I n c . , T o r o n t o , Canada.

2 ~ . ~ . Helmeste i s an O c c u p a t i o n a l H e a l t h S p e c i a l i s t w i t h MacZaren P l a n s e a r c h I n c . , T o r o n t o , Canada.

3 ~ . ~ . Tamura i s a S e n i o r Research O f f i c e r , Energy and S e r v i c e s S e c t i o n , D i v i s i o n of B u i l d i n g R e s e a r c h , N a t i o n a l R e s e a r c h C o u n c i l of Canada, Ottawa, Canada.

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The r e l a t i o n between a i r i n f i l t r a t i o n r a t e and i n d o o r

c o n c e n t r a t i o n s of radon g a s , r a d o n d a u g h t e r s , a n d formaldehyde h a s been i n v e s t i g a t e d f o r b o t h summer and w i n t e r c o n d i t i o n s i n a

number of T o r o n t o h o u s e s w i t h low r a t e s of n a t u r a l v e n t i l a t i o n .

A i r i n f i l t r a t i o n r a t e s o b t a i n e d by t h e f a n d e p r e s s u r i z a t i o n method

and t h e s u l f u r h e x a f l u o r i d e t r a c e r g a s d i l u t i o n method a r e

compared. Formaldehyde l e v e l s were monitored u s i n g b o t h t h e

r e v i s e d NIOSH i m p i n g e r sampling method a n d badge d o s i m e t e r s . L e v e l s of radon g a s and d a u g h t e r s were d e t e r m i n e d by a g r a b

s a m p l i n g t e c h n i q u e and by f i l m d o s i m e t e r a s w e l l f o r r a d o n

d a u g h t e r s .

Average a i r change r a t e s i n a i r - c o n d i t i o n e d h o u s e s were lower o v e r

t h e summer months (0.12

-

0.40 a c h ) t h a n o v e r t h e w i n t e r p e r i o d

(0.21

-

0.66 a c h ) . The a v e r a g e summer i n d o o r formaldehyde

c o n c e n t r a t i o n f o r a i r - c o n d i t i o n e d h o u s e s was 0.076 ppm a s compared

w i t h an a v e r a g e of 0.038 ppm i n w i n t e r . The a v e r a g e r a d o n and

radon d a u g h t e r c o n c e n t r a t i o n s f o r a i r - c o n d i t i o n e d h o u s e s were h i g h e r by 44% and 32%, r e s p e c t i v e l y , d u r i n g t h e summer months t h a n d u r i n g t h e w i n t e r months.

INTRODUCTION

Prolonged e x p o s u r e t o low c o n c e n t r a t i o n s of i n d o o r a i r

c o n t a m i n a n t s c a n under c e r t a i n c i r c u m s t a n c e s b e a s e r i o u s t h r e a t

t o t h e h e a l t h of b u i l d i n g o c c u p a n t s . I n r e c e n t y e a r s c o n s i d e r a b l e

a t t e n t i o n h a s been f o c u s s e d on formaldehyde g a s e m i s s i o n s from u r e a formaldehyde foam i n s u l a t i o n a n d , i n a r e a s of h i g h n a t u r a l r a d i o a c t i v i t y , o n p a r t i c u l a t e a i r b o r n e r a d i o a c t i v i t y ( r a d o n

d a u g h t e r s ) r e s u l t i n g from r a d i o a c t i v e decay of r a d o n g a s . With

t h e i n c r e a s i n g demand f o r improvement i n a i r t i g h t n e s s o f t h e b u i l d i n g e n v e l o p e a s an e n e r g y c o n s e r v a t i o n measure, t h e p o t e n t i a l f o r s u c h c o n t a m i n a n t s t o b e p r e s e n t a t a n u n a c c e p t a b l e l e v e l , e v e n i n t h e a b s e n c e of s i g n i f i c a n t s o u r c e s , h a s i n c r e a s e d .

Formaldehyde g a s , f o r example, c a n b e t r a c e d t o s o u r c e s s u c h a s s y n t h e t i c f a b r i c s , wood p r o d u c t s , and p r o d u c t s of combustion. Radon g a s , a decay p r o d u c t of n a t u r a l l y - o c c u r r i n g n u c l i d e r a d i u n r 226, can be found t o some e x t e n t i n most s o i l s t h r o u g h o u t t h e

world. Radon emanates from e a r t h - d e r i v e d b u i l d i n g m a t e r i a l s a n d

can e n t e r a b u i l d i n g by t r a n s p o r t from s u r r o u n d i n g s o i l t h r o u g h c r a c k s and o p e n i n g s i n f o u n d a t i o n s .

T h i s paper p r e s e n t s a summary of t h e r e s u l t s of a m o n i t o r i n g

program d e s i g n e d t o examine t h e r e l a t i o n between i n f i l t r a t i o n r a t e and i n d o o r c o n c e n t r a t i o n s of r a d o n , radon d a u g h t e r s and

formaldehyde i n h o u s e s h a v i n g r e l a t i v e l y low r a t e s of n a t u r a l

v e n t i l a t i o n . It a l s o compares a i r i n f i l t r a t i o n d a t a o b t a i n e d by

t h e f a n d e p r e s s u r i z a t i o n and t r a c e r g a s d i l u t i o n methods. Twelve

h o u s e s i n M e t r o p o l i t a n Toronto were t e s t e d weekly d u r i n g t h e

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were

t e s t e d a l s o d u r i n g t h e summer f r o m J u l y t o September 1982; e i g h t of t h e t e n used t h e i r c e n t r a l a i r - c o n d i t i o n i n g systems e x t e n s i v e l y .

2. DESCRIPTION OF TEST HOUSES

E l e c t r i c a l l y h e a t e d h o u s e s w i t h f o r c e d warm-air s y s t e m s were

s e l e c t e d f o r t h e t e s t program b e c a u s e t h e i r a i r exchange i s n o t

augmented by a f u r n a c e chimney. Two-storey, s i n g l e - f a m i l y

d w e l l i n g s w i t h basements a n d n o u r e a formaldehyde foam i n s u l a t i o n

were s t u d i e d ; t h e i r volumes, i n c l u d i n g basements, r a n g e d from 555

t o 948 m3. A l l w e r e frame c o n s t r u c t i o n w i t h b r i c k s i d i n g , t e n y e a r s o l d o r l e s s , w i t h c e n t r a l a i r - c o n d i t i o n i n g and f i r e p l a c e s . S e l e c t i o n of t h e t w e l v e t e s t h o u s e s from a p o o l of e i g h t e e n was based on low n a t u r a l v e n t i l a t i o n r a t e , c h a r a c t e r i z e d by t h e o v e r a l l a i r l e a k a g e p r o p e r t i e s a s s e s s e d by t h e f a n d e p r e s s u r i z a t i o n method (CGSB I n t e r i m S t a n d a r d 149-GP-10, "Determination of A i r T i g h t n e s s of B u i l d i n g s by t h e Fan D e p r e s s u r i z a t i o n Method"). It g i v e s t h e t i g h t n e s s o f a b u i l d i n g

e n c l o s u r e by e x h a u s t i n g a i r from t h e s t r u c t u r e and measuring t h e a i r f l o w r a t e a n d c o r r e s p o n d i n g p r e s s u r e d i f f e r e n c e a c r o s s t h e

e n c l o s u r e . A p o r t a b l e commercial e x h a u s t f a n u n i t developed by

Orr and F i g l e y l was u s e d .

3. MONITORING AND ANALYTICAL TECHNIQUES

Weekly a i r sampling c o n s i s t e d of t a k i n g g r a b samples f o r

r a d o n / r a d o n d a u g h t e r s a n d formaldehyde a n a l y s i s a n d c o n c u r r e n t measurements of a i r exchange r a t e u s i n g t h e t r a c e r g a s d i l u t i o n

method. Thermohygrographs were i n s t a l l e d i n t h e 1 i v i n g room t o

measure i n d o o r t e m p e r a t u r e and r e l a t i v e humidity. Outdoor

e n v i r o n m e n t a l c o n d i t i o n s , i n c l u d i n g t e m p e r a t u r e , r e l a t i v e

humidity, wind speed and d i r e c t i o n , and a t m o s p h e r i c p r e s s u r e were

r e c o r d e d a t t h e t i m e of sampling. Door a n d window o p e n i n g s a n d

occupant a c t i v i t i e s (vacuuming, smoking, e t c . ) were n o t e d f o r e a c h s a m p l i n g p e r i o d . 3.1 A i r I n f i l t r a t i o n I n t h e t r a c e r g a s d i l u t i o n method t h e i n f i l t r a t i o n r a t e can b e d e t e r m i n e d from t h e e x p o n e n t i a l d e c a y r a t e of t h e t r a c e r g a s c o n c e n t r a t i o n w i t h r e s p e c t t o t i m e . I f t h e n a t u r a l l o g a r i t h m o f t h e c o n c e n t r a t i o n i s p l o t t e d a g a i n s t t i m e , t h e measurements s h o u l d f a l l on a s t r a i g h t l i n e p r o v i d e d t h e a i r change r a t e r e m a i n s c o n s t a n t . A s c a t t e r of p o i n t s i s e x p e c t e d a n d a s t r a i g h t l i n e b e s t f i t can be c a l c u l a t e d u s i n g t h e l e a s t s q u a r e s method.

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The a i r change r a t e i s g i v e n by where C1 = c o n c e n t r a t i o n of t r a c e r g a s a t time t l

C2

= c o n c e n t r a t i o n of t r a c e r g a s a t t i m e t S = a i r change r a t e p e r u n i t t i m e . I n e a c h of t h e t e s t houses 50 c c of SF6 ( a s a t r a c e r g a s ) was i n j e c t e d u p s t r e a m of t h e f a n i n t o t h e r e t u r r r a i r plenum of t h e

f o r c e d - a i r h e a t i n g system. Samples were drawn a t t h e same

l o c a t i o n f o r s u b s e q u e n t a n a l y s i s o f SF6 c o n c e n t r a t i o n 30, 45, 60

and 75 min a f t e r i n j e c t i o n . During t h e sampling p e r i o d t h e

f u r n a c e f a n was s w i t c h e d t o manual mode i n o r d e r t o a c h i e v e thorough and c o n t i n u o u s mixing of a i r w i t h i n t h e s t r u c t u r e .

Connecting d o o r s , c l o s e t d o o r s , r e g i s t e r s , e t c .

,

were opened t o

a l l o w f r e e c i r c u l a t i o n of a i r . Windows, e x t e r i o r d o o r s and

f i r e p l a c e dampers were c l o s e d .

T r a c e r g a s i n j e c t i o n and sample e x t r a c t i o n from t h e r e t u r n - a i r

pleneum was a c h i e v e d u s i n g a hypodermic s y r i n g e . The t r a n s f e r of

SF6 from a g a s c y l i n d e r t o t h e 50-cc s y r i n g e was accomplished

o u t s i d e and downwind of t h e t e s t house. A c l e a n 50-c s y r i n g e a n d

n e e d l e were u s e d t o draw sample a i r from t h e r e t u r n - a i r plenum f o r i n j e c t i o n i n t o a 20-mL e v a c u a t e d g l a s s t u b e f o r temporary s t o r a g e and s u b s e q u e n t a n a l y s i s i n t h e l a b o r a t o r y w i t h a n e l e c t r o n - c a p t u r e dectector/chromatograph.

3.2 Formaldehyde

Formaldehyde l e v e l s were monitored f o l l o w i n g t h e r e v i s e d NIOSH ( N a t i o n a l I n s t i t u t e f o r O c c u p a t i o n a l S a f e t y a n d H e a l t h ) i m p i n g e r

sampling method developed by R.R. Miksch a t t h e U n i v e r s i t y of

C a l i f o r n i a , and u s i n g a 1-h sampling p e r i o d . Samples were t a k e n

i n t h e l i v i n g room o r d i n i n g room of e a c h h o u s e , w i t h t h e sampling

t r a i n l o c a t e d a p p r o x i m a t e l y 1 m above f l o o r l e v e l . A c a l i b r a t e d

c o n s t a n t - f l o w pump was used t o draw a i r a t 1 L/min t h r o u g h a

midget impinger c o n t a i n i n g sodium b i s u l f i t e a b s o r b i n g s o l u t i o n f o r s u b s e q u e n t a n a l y s i s i n a s p e c t r o p h o t o m e t e r .

For comparison, formaldehyde badge d o s i m e t e r s c o n t a i n i n g sodium b i s u l f i t e s o l u t i o n were u s e d t o c o l l e c t s a m p l e s o v e r a s e v e r r d a y

p e r i o d . Badges were suspended a p p r o x i m a t e l y 1 m above t h e f l o o r

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Radon /Itadon D a u g h t e r s

Simultaneous r a d o n l r a d o n d a u g h t e r s a m p l e s were c o l l e c t e d from t h e

basement a r e a of e a c h h o u s e u s i n g a g r a b s a m p l i n g t e c h n i q u e . A l l

measurements were t a k e n a p p r o x i m a t e l y 1 m above t h e f l o o r . For

r a d o n g a s sampling, s e v e r a l c h a n g e s of basement room a i r were

drawn t h r o u g h a z i n c s u l p h i d e - c o a t e d flow-through s c i n t i l l a t i o n c e l l a f t e r p a s s i n g a g l a s s f i b r e f i l t e r t o e x c l u d e d a u g h t e r

p a r t i c l e s . The radon g a s c o l l e c t e d i n s i d e t h e c e l l was a l l o w e d t o

d e c a y f o r a p p r o x i m a t e l y 4 h ( s e v e n h a l f - l i v e s o f s h o r t - l i v e d

d a u g h t e r c h a i n ) , a t which t i m e t h e d a u g h t e r s were v i r t u a l l y a t

e q u i l i b r i u m w i t h t h e p a r e n t radon. The c e l l was t h e n p l a c e d

i n s i d e a l i g h t - t i g h t c a s t l e c o n t a i n i n g a p h o t o m u l t i p l i e r t u b e c o n n e c t e d t o a s c a l e r / c o u n t e r . The a l p h a p a r t i c l e s r e s u l t i n g f r o m r a d i o a c t i v e decay i n t e r a c t w i t h t h e z i n c s u l p h i d e c o a t i n g of t h e c e l l t o produce t h e s c i n t i l l a t i o n s o b s e r v e d by t h e c o u n t i n g system. C a l i b r a t i o n of e a c h c e l l c o u n t e r s y s t e m a g a i n s t a known r a d o n s o u r c e y i e l d s a c o u n t p e r m i n u t e t o p i c 0 c u r i e p e r l i t r e (pCi/L) c o n v e r s i o n a f t e r s u b t r a c t i n g t h e p r e d e t e r m i n e d background c o u n t f o r t h e c e l l .

Radon d a u g h t e r c o n c e n t r a t i o n s were d e t e r m i n e d by means of t h e

m o d i f i e d Kusnetz method. A high-volume a i r pump w i t h a c a p a c i t y

of 30 L/min was u s e d t o draw a i r t h r o u g h a g l a s s f i b r e f i l t e r f o r

1 0 min. The p a r t i c u l a t e r a d o n d a u g h t e r s c o l l e c t e d o n t h e f i l t e r

were t h e n c o u n t e d w i t h a p o r t a b l e a l p h a c o u n t e r i n c o r p o r a t i n g a p h o t o n u l t i p l i e r t u b e d e t e c t o r .

For comparison w i t h g r a b s a m p l i n g d a t a , t h r e e radon d o s i m e t e r s were exposed i n e a c h h o u s e (two i n t h e basement, o n e o n t h e main

f l o o r ) o v e r a four-month s a m p l i n g p e r i o d . Alpha p a r t i c l e s from

t h e d e c a y of r a d o n g a s and d a u g h t e r s bombarding a n a l p h e s e n s i t i v e p l a s t i c f i l m d e t e c t o r (mounted on a c a r d ) l e a v e r a d i a t i o n t r a c k s . A n a l y s i s of t h e d o s i m e t e r s was c a r r i e d o u t by t h e m a n u f a c t u r e r . 4 . _{DATA ANALYSIS} 4.1 A i r I n f i l t r a t i o n F i g u r e 1 shows t h e a v e r a g e a i r change of e a c h h o u s e f o r b o t h w i n t e r and summer months, o b t a i n e d by t h e t r a c e r g a s d i l u t i o n method and t h e a i r change r a t e f o r e a c h h o u s e ; t h i s r a n g e d from

3.9 t o 7.9 a i r c h a n g e s p e r h o u r ( a c h ) , o b t a i n e d by t h e f a n

d e p r e s s u r i z a t i o n method a t a p r e s s u r e d i f f e r e n c e a c r o s s t h e

b u i l d i n g e n v e l o p e of 50 Pa. From a' b e s t f i t l i n e drawn t h r o u g h

t h e p o i n t s , t h e r a t i o of a i r i n f i l t r a t i o n r a t e s measured by t h e t r a c e r g a s method and f a n d e p r e s s u r i z a t i o n method was 1 / 1 4 f o r w i n t e r and 1/20 f o r summer.

F i g u r e 2 shows t h e a v e r a g e i n f i l t r a t i o n r a t e of e a c h h o u s e ,

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0

u

2 a b R I N F I L T R A T I O N A T 5 0 P a , A I R C H A N G E S l h ( F A N D E P R E S S U R I Z A T I O N M E T H O D ] I I _I _I

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W l N T E R --+-

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.//.

.1 - 11. 5

.

8 - I I I 1 I F i g u r e 1 Comparison of a i r i n f i l t r a t i o n r a t e s d e t e r m i n e d by t h e t r a c e r g a s d i l u t i o n and t h e f a n d e p r e s s u r i z a t i o n methods H O U S E N U M B E R F i g u r e 2 Average a i r i n f i l t r a t i o n r a t e s ( t r a c e r g a s d i l u t i o n method) ( w i t h r a n g e of two s t a n d a r d d e v i a t i o n s )

(10)

t e s t i n g . I n f i l t r a t i o n r a t e s f o r a i r - c o n d i t i o n e d h o u s e s o v e r t h e

summer months (0.12

-

0.40 a c h ) were lower t h a n t h o s e o v e r t h e

w i n t e r p e r i o d (0.2 1

-

0.66 a c h )

.

I n two h o u s e s i n which a i r

c o n d i t i o n e r s were n o t u s e d and windows were open t h e a i r change

r a t e s were much h i g h e r (1.75 a c h f o r House No. 7 , and 2 . 7 8 a c h f o r

House No. 4). The a p p a r e n t r e l a t i v e l y h i g h a i r change r a t e i n

House No. 10 i n summer may b e r e l a t e d t o a i r c i r c u l a t i o n , inasmuch

a s o n l y one of two f u r n a c e f a n s i s u s e d f o r c i r c u l a t i o n of c o o l i n g

a i r i n summer. The g r a d u a l d i f f u s i o n o f S F 6 i n t o u n c i r c u l a t e d

a r e a s would g i v e t h e e f f e c t of more r a p i d decay of t r a c e r g a s c o n c e n t r a t i o n , r e s u l t i n g i n a n i n c o r r e c t l y h i g h a p p a r e n t a i r exchange r a t e .

F i g u r e 3 p r e s e n t s a v e r a g e a i r c h a n g e s , wind s p e e d s , a n d

h e a t i n g / c o o l i n g d e g r e e d a y s f o r e i g h t a i r - c o n d i t i o n e d h o u s e s i n t h e summer months and f o r t w e l v e h o u s e s i n t h e p r e v i o u s w i n t e r .

A i r change r a t e s were s i g n i f i c a n t l y l e s s i n t h e summer months t h a n

i n t h e w i n t e r months when t h e r e a r e g r e a t e r i n d o o r l o u t d o o r t e m p e r a t u r e d i f f e r e n t i a l s .

SAMPLING PERIOD SAMPLING PERIO! 2 NOV 1981 TO 12 JULY 1982 TO 12 MARCH 1982 16 SEPT 1982

-

Pr I \

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\, A I R CHANGE RATE

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b 4

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I 6 - OEGREF-DAYS 0 4 - 2

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NOV DEC JAN FEB MARCH 1U1 Y AUG SEPT

F i g u r e 3 Average p e r i o d a i r i n f i l t r a t i o n r a t e , wind s p e e d and

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It i s e x p e c t e d t h a t d u r i n g t h e summer when t h e t e m p e r a t u r e d i f f e r e n t i a l s a r e low t h e a i r change r a t e w i l l be due mainly t o

wind. T h e r e a p p e a r s t o b e a p o s i t i v e c o r r e l a t i o n between a i r

change r a t e and wind s p e e d f o r s e v e r a l of t h e e i g h t a i r -

c o n d i t i o n e d h o u s e s . I n c r e a s e d i n d o o r r e l a t i v e h u m i d i t y c a u s e s i n c r e a s e d a i r t i g h t n e s s d u r i n g t h e summer months and may a l s o b e a f a c t o r i n t h e d e c r e a s e d a i r change r a t e 4 ; w i n t e r a v e r a g e s of

r e l a t i v e h u m i d i t y ranged from 34 t o 47%, and summer a v e r a g e s r a n g e d f r o m 56 t o 65%.

4.2 Formaldehyde

The mean i n d o o r formaldehyde c o n c e n t r a t i o n s o b t a i n e d from 1-h

NIOSH measurements i n e a c h of t h e h o u s e s a r e shown on F i g u r e

4.

I n g e n e r a l , t h e r e was good agreement between t h e weekly d o s i m e t e r ( 7 d a y e x p o s u r e ) and 1-h NIOSH r e s u l t s o v e r t h e w i n t e r s a m p l i n g

p e r i o d , a s shown g r a p h i c a l l y i n F i g u r e 5. Agreement was poor when

t h e y were compared on a weekly b a s i s f o r e a c h house. The h i g h e r

i n d o o r formaldehyde l e v e l s i n a i r - c o n d i t i o n e d h o u s e s a p p e a r t o b e

r e l a t e d t o a l o w e r a i r change r a t e d u r i n g t h e summer months. The

a v e r a g e i n d o o r c o n c e n t r a t i o n f o r t h e a i r - c o n d i t i o n e d h o u s e s was

0.076 ppm, which i s t w i c e t h e w i n t e r a v e r a g e o f 0.038 ppm. The

l e v e l s of formaldehyde c o n c e n t r a t i o n i n d o o r s a p p e a r t o be

a f f e c t e d , a s w e l l , by t h o s e o u t d o o r s . Measurements d u r i n g t h e

summer t e s t s i n d i c a t e d t h a t o u t d o o r l e v e l s n e a r a highway and a

major r o a d ( d i s t a n c e of 25 t o 120 m) v a r i e d f r o m 0.014 t o

0.022 ppm, and n e a r minor r o a d s from 0.006 t o 0.008 ppm. Outdoor

l e v e l s a r e a f f e c t e d by t r a f f i c d e n s i t y s i n c e a u t o m o b i l e e x h a u s t c o n t a i n s s i g n i f i c a n t c o n c e n t r a t i o n s of formaldehyde and o t h e r a l d e h y d e s . A t p r e s e n t t h e a c c e p t e d i n d o o r l e v e l of formaldehyde i s 0.10 ppm (ASHRAE S t a n d a r d 62-81, V e n t i l a t i o n f o r A c c e p t a b l e I n d o o r Air Q u a l i t y ) . I n t h r e e of t h e t e s t h o u s e s t h i s l e v e l was exceeded i n

70% of t h e i n d o o r measurements made d u r i n g t h e summer months.

Over t h e w i n t e r months t h e same t h r e e h o u s e s a l s o had t h e h i g h e s t formaldehyde c o n c e n t r a t i o n s , h u t t h e maximum a c c e p t a b l e

c o n c e n t r a t i o n was exceeded i n less t h a n 10% of t h e measurements.

4.3 RadonIRadon D a u g h t e r s

F i g u r e 6 shows a v e r a g e d radon c o n c e n t r a t i o n s and F i g u r e 7 a v e r a g e d r a d o n d a u g h t e r c o n c e n t r a t i o n s f o r t h e two measurement p e r i o d s . Average radon c o n c e n t r a t i o n s o v e r t h e w i n t e r p e r i o d r a n g e d f r o m 0.3 t o 2.2 p C i / ~ ; o v e r t h e summer p e r i o d t h e y r a n g e d from 0.37 t o

2.26 pCi/L. Average radon d a u g h t e r c o n c e n t r a t i o n s o v e r t h e w i n t e r

p e r i o d r a n g e d f r o m 0.0007 t o 0.0065 working l e v e l

(WL);

c o r r e s p o n d i n g summer d a t a ranged from 0.0011 t o 0.007

WL.

Comparison o f summer a n d w i n t e r d a t a f o r t h e e i g h t a i r - c o n d i t i o n e d

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H O U S E N U M B E R

Figur.e 4 . Average 1-h NIOSH formaldehyde concentrations ( i n t e r i o r ) ( w i t h range of two standard d e v i a t i o n s )

E

l

SAMPLING PERIOD CL

n ₂_{NOV 1981 TO 12 MARCH 1982}

W

n (SEASON AVERAGE FOR EACH TEST HOUSE)

1 - H O U R N I O S H . F O R M A L D E H Y D E . P P m

Figure 5 Comparison 6f average 1-h NIOSH and 7-day dosimeter formaldehyde measurements

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H O U S E N U M B E R

F i g u r e 6 Average d a i l y radon c o n c e n t r a t i o n ( w i t h r a n g e of two s t a n d a r d d e v i a t i o n s ) 0 . 0 1 2 1 1 1 1 1 1 1 1 1 1 1 ~ SAhlPLlNG PERIOD 1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 H O U S E N U M B E R F i g u r e 7 Average d a i l y radon d a u g h t e r c o n c e n t r a t i o n s ( w i t h r a n g e of two s t a n d a r d d e v i a t i o n s )

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G R A B S A M P L E . R A D O N D A U G H T E R S , W L

0 . 0 1 0 0 . 0 0 8 0 . 0 0 6 0 . 0 0 4 0 . 0 0 2 0

1 ' I T 1 I ' 4

SAMPLING PERIOD

3 2 NOV 1981 TO 12 MARCH 1982

(SEASON AVERAGE FOR

d

-... EACH TEST HOUSE) - 0 . 0 0 2 v;

.-

Dz U n vl n 0 n 4 0 Dz Y W I-

-

_{0 . 0 0 8}

:

-

vl

-

0 . 0 1 0 I t 1 1 1 1 1 1 1 1 1 1 1 1 0 1 2 3 G R A B S A M P L E , R A D O N G A S , p C i l L RADON RADON DAUGHTERS AVERAGE E Q U I L I B R I U M FACTOR

-

0.31

F i g u r e 8 Comparison of g r a b sample and f i l m d o s i m e t e r measurements of r a d o n a n d r a d o n d a u g h t e r c o n c e n t r a t i o n s

P

c o n c e n t r a t i o n s were g r e a t e r f o r t h e summer months t h a n f o r t h e w i n t e r months by 44 and

32%,

r e s p e c t i v e l y . The a c c e p t a b l e l i m i t f o r r a d o n d a u g h t e r s i s 0.01

WL

(ASHRAE

S t a n d a r d 62-81). The r a d o n l r a d o n d a u g h t e r d a t a showed e x p e c t e d v a r i a t i o n s i n i n d i v i d u a l s a m p l e s t a k e n a t t h e same h o u s e on d i f f e r e n t s a m p l i n g d a y s . It can be e x p l a i n e d , a t l e a s t i n p a r t , by t h e e f f e c t s of v a r i o u s m e t e o r o l o g i c a l f a c t o r s shown i n o t h e r s t u d i e s t o b e s t a t i s t i c a l l y s i g n i f i c a n t i n a f f e c t i n g t h e e m i s s i o n r a t e of radon g a s from s o i l . These i n c l u d e b a r o m e t r i c p r e s s u r e , a i r and s o i l t e m p e r a t u r e ,

r e l a t i v e h u m i d i t y , and wind speed.

The a v e r a g e e q u i l i b r i u m f a c t o r ( t h e r a t i o of measured r a d o n

d a u g h t e r s t o t h e p o t e n t i a l r a d o n d a u g h t e r c o n c e n t r a t i o n t h a t c o u l d o c c u r when i n complete e q u i l i b r i u m w i t h t h e p a r e n t r a d o n ) d i d n o t

change s i g n i f i c a n t l y from w i n t e r (0.33) t o summer (0.30) i n t h e e i g h t a i r - c o n d i t i o n e d houses. F i g u r e 8 p r o v i d e s a comparison of a v e r a g e r a d o n and r a d o n d a u g h t e r measurements f o r e a c h h o u s e , u s i n g a g r a b sampling t e c h n i q u e w i t h d a t a o b t a i n e d from t h e f i l m d o s i m e t e r s exposed o v e r t h e w i n t e r s a m p l i n g p e r i o d . Agreement between t h e two s e t s of d a t a can be c o n s i d e r e d f a i r l y good. F i g u r e 9 s u g g e s t s t h a t c o n c e n t r a t i o n s o f b o t h formaldehyde. a n d radon g a s t e n d t o d e c r e a s e a s t h e a i r change r a t e i n c r e a s e s a n d v i c e v e r s a .

(15)

I

WINTER DATA SUMMER DATA

I

- 0 FORMALDEHYDE - A RADON \

'<

,/

- O\. RADON \ l o

-

o->:, w

-

-:z, .A"- -0 / \,-- / - - ,o FORMALDEHYDE

-

- L o

NOV OEC JAN FEB MARCH JULY AUG SEPT NOTE: HOUSES 4 AND 7 WERE EXCLUDED FROM AVERAGES

FOR JULY, AUGUST AND SEPTEMBER BECAUSE OF "OPEN" SAMPLING CONDITIONS EXPERIENCED

F i g u r e 9 Average m o n t h l y ' a i r i n f i l t r a t i o n r a t e and formaldehyde

and r a d o n c o n c e n t r a t i o n s

5.

SUMMARY

The p o s s i b l e c o r r e l a t i o n between a i r i n f i l t r a t i o n r a t e and i n d o o r c o n c e n t r a t i o n s of r a d o n , r a d o n d a u g h t e r s , a n d formaldehyde i n h o u s e s h a v i n g r e l a t i v e l y low r a t e s of n a t u r a l v e n t i l a t i o n h a s been examined.

1. A i r change r a t e s measured by t h e f a n d e p r e s s u r i z a t i o n method

v a r i e d f r o m 3.9 t o 7.9 a i r c h a n g e s p e r h o u r a t a p r e s s u r e

d i f f e r e n c e of 50 Pa. Averaged i n f i l t r a t i o n r a t e s o b t a i n e d by

t r a c e r g a s measurements o v e r t h e summer s t u d y p e r i o d ( f o r a i r

c o n d i t i o n e d h o u s e s ) ranged from 0.12 t o 0.40 a i r changes p e r

h o u r ; o v e r t h e w i n t e r months t h e r a t e s were h i g h e r a t 0.21 t o

0.66 a i r changes p e r hour. These measurements r e p r e s e n t 1 / 2 0

and 1 / 1 4 , r e s p e c t i v e l y , o f t h e a i r change r a t e s a s measured by t h e f a n d e p r e s s u r i z a t i o n method a t a p r e s s u r e d i f f e r e n c e of 5 0 Pa. 2. The a v e r a g e d i n d o o r c o n c e n t r a t i o n of formaldehyde f o r a l l a i r - c o n d i t i o n e d h o u s e s , a s measured by t h e 1-h N I O S H method, was 0.076 ppm ( r a n g i n g from 0.019 t o 0.136 ppm) d u r i n g t h e summer months, a n d 0,038 ppm ( r a n g i n g f r o m 0.015 t o 0.059 ppm) f o r t h e w i n t e r months,

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3. The a v e r a g e d r a d o n g a s c o n c e n t r a t i o n s f o r a l l a i r c o n d i t i o n e d h o u s e s d u r i n g t h e summer months r a n g e d from 0.37 t o

2.26 pCi/L; f o r t h e w i n t e r months t h e y r a n g e d f r o m 0.30 t o

2.2 pCi/L. The a v e r a g e d radon d a u g h t e r c o n c e n t r a t i o n s f o r a l l

a i r - c o n d i t i o n e d h o u s e s d u r i n g t h e summer months r a n g e d from

0.0011 t o 0.007

WL;

f o r t h e w i n t e r months t h e y ranged from

0.0007 t o 0.0065

WL.

4. Measurements i n d i c a t e t h q t c o n c e n t r a t i o n s of formaldehyde,

r a d o n , and r a d o n d a u g h t e r s a r e a f f e c t e d by i n f i l t r a t i o n r a t e .

6. REFERENCES

1. ORR, H.W. and FIGLEY, D.A., "An e x h a u s t f a n a p p a r a t u s f o r

a s s e s s i n g t h e a i r l e a k a g e c h a r a c t e r i s t i c s of h o u s e s , " N a t i o n a l Research Council of Canada, D i v i s i o n of B u i l d i n g Research,

BR Note 156, 1980.

2. TAMURA, G.T.,

ASHRAE

J o u r n a l ,

25,

No. 1 0 , 1983, pp. 40-43.

3. KUSNETZ, H.L., American I n d u s t r i a l Hygiene A s s o c i a t i o n

Q u a r t e r l y ,

-

17, 1956, p. 85.

4.

YOCOM, J.E., J o u r n a l of t h e A i r P o l l u t i o n C o n t r o l A s s o c i a t i o n ,

32 No. 5 , 1982, pp. 500-520.

-9

7. ACKNOWLEDGEMENTS

The a u t h o r s would l i k e t o acknowledge t h e c o n t r i b u t i o n of t h e

f o l l o w i n g k e y p r o j e c t team members: J. D e Jong, W. Cormack and

R. Whitehead of MacLaren E n g i n e e r s , and

R.

Evans of t h e N a t i o n a l

R e s e a r c h C o u n c i l o f Canada. The c o o p e r a t i o n a n d a s s i s t a n c e of

North York Hydro and t h e i n d i v i d u a l homeowners who p a r t i c i p a t e d i n t h e s t u d y a r e much a p p r e c i a t e d .