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outdoor relationship of ammonia concentrations in selected office buildings
The Science of the Total Enuironment, 61 (1987) 73 77 Elsevier Science Publishers B.V., Amsterdam ~ Printed
INDOOR/OUTDOOR CONCENTRATIONS
ANICA Institute (Received
$IsOVIc,
KRESIMIR
for Medical April
RELATIONSHIP IN SELECTED
22nd.
Research
VEGA and
and
May
llth,
Netherlands
OF AMMONIA OFFICE BUILDINGS
NATASA
Occupational
1986; accepted
73 in The
KALINIC Health,
41001
Zagreb,
POB
291 (Yugoslavia)
1986)
ABSTRACT Ammonia concentrations in air were measured simultaneously outdoors and in six offices of five modern buildings in summer and in winter. The concentrations outdoors were generally low, but significantly higher in summer than in winter. The concentrations indoors exceeded several times those outdoors, but showed no systematic seasonal differences. Concentrations of > lOOpgm-” measured in the most recently constructed buildings indicate that more attention should be paid to the possible indoor sources of ammonia. INTRODUCTION
People in moderate climates spend considerably more time indoors than outdoors, but only recently have measurements of human exposure to air pollutants been more frequently performed indoors [l] rather than outdoors. In an attempt to use earlier data obtained for outdoor measurements for assessing previous exposure indoors, simultaneous measurements indoors and outdoors were performed in order to determine conversion factors. It has been shown that an indoor/outdoor relationship can only be established for those pollutants which are not released indoors, and that the ratio depends on the concentration, infiltration rates and reactivity of the pollutants [2]. Ammonia is an air pollutant and a very important component of the nitrogen cycle. Concentrations outdoors are usually low [3], except in the vicinity of industrial sources, farm houses and agricultural applications. Indoors, ammonia may originate from cleaning agents, metabolic processes, smoking or from external sources. Although ammonia is on the list of chemical irritants which may cause bronchial asthma [4], its presence in indoor environments has been neglected, as it is not considered to be a non-occupational hazard, and therefore is not included in guidelines for indoor air quality. The purpose of our investigation was to undertake a preliminary assessment of ammonia concentrations in a limited number of modern offices, s,ituated in different parts of Zagreb, with different heating and ventilation systems, and t.o establish their relation to the outdoor concentrations.
0048.9697/87/$03.50
1~~‘1987 Elsevier
Science
Publishers
B.V
74 EXPERIMENTAL
Sampling
programme
Simultaneous samples were collected outdoors and within six offices of five buildings over a period of l&12 days at each sampling site, both in the winter and summer of 1983. The buildings were located as follows (the year the building first started to be used is in parentheses): A-l,2 (1973) business quarter adjacent to industrial area (room A-2 has recently been renovated); B (1982) industrial area; C (1983) the city centre; D (1982) business quarter adjacent to industrial area; E (1983) residential area. Buildings A, B, C and D are large office buildings with forced ventilation systems, while building E is smaller and has no forced air ventilation. In building D the windows were sealed, while in other buildings with forced ventilation, some of the windows of each room could be opened. Space heating was provided in building A by air conditioning, in buildings B and C 30% by air conditioning and 70% by a hot water system, while in buildings D and E only by a gas-fired hot water system. Sampling
procedure
Samples were collected on a 5 cm2 area of Whatman No. 1 filter papers at a flow rate of 1.8 dm3 mini’ and with the exposure area impregnated with a solution of oxalic acid in ethanol [5]. The total volume of air sampled over 24 h was recorded by a gasmeter. Analysis
of samples
After samples had been collected the impregnated filters were immersed in 50 cm3 of H,O, solution. To a 9 cm3 aliquot of the extract 1 cm3 of Nessler reagent was added and the absorbance was measured at 440nm. RESULTS
AND
DISCUSSION
The results of measurements are presented in Table 1 for summer and in Table 2 for winter as number of measurements, arithmetic means (X) and range of NH, concentrations measured outdoors (Out) and indoors (In) as well as the In/Out ratios and Spearman correlation coefficients (r) between indoor and outdoor concentrations. The relationship between average winter and summer concentrations outdoors and indoors is shown in Table 3. Ammonia concentrations indoors were systematically several times higher than those outdoors at all sites, both in summer and in winter (Fig. l), which indicates that the source must have been indoors. In some cases, however, there was a significant correlation between indoor and outdoor ammonia concentrations (at sites B, C and D in summer and at site E in winter), which is difficult
IO
TABLE
1
Indoor/outdoor Site
A-l
relationship
10 10
8
12
C D E
12
TABLE
2
10 10
Indoor/outdoor Site
Range
15.5 16.9 18.9 18.7 13.5
8.5 22.0 4.7-27.0
4.2 14.4
B
11 13
n E,
12
8.7
10
9.3
TABLE
3
Seasonal Site
variations
C
D E
Range
x
Range
41.9
26.3-53.0
2.1
2.0~ 5.8
0.31
> 0.05
58.5 58.5
38.G75.7 44.4- 75.4
3.7 3.5
2.34.3
0.04
$0.05
2.1-9.5
0.79
60.2
5.4 6.7
2.s24.9 4.6 20.0
0.86 0.44
< 0.01 < 0.01 < 0.01
3.7
l.M.6
0.55
> 0.05
49.2
of ammonia
15.5 16.9 18.9 18.7 13.5
134.7
83.8~169.1 29.670.8
concentrations Indoors
0.9
X
17.9
0.~9.0 5.3-48.7 2.3 20.7 2.c21.2
in average
ammonia
Range
(agm
“) ~
ratio
x
Range
32.8-48.2 23.764.4
7.1 9.3
44.3 167.0
30.M7.2 128 281
10.5 11.6 4.9 6.1
42.3 56.9
25.7 53.3 42.C77.4
concentrations
r
P
winter
In/Out
38.5 50.2
Outdoors Summer
A-l A-2 B
ratio
7.7-20.9
10
c
In/Out
103.0 131.2
Range
5.4
summer
Z
Outdoors
10
~
3.S25.6 4.2-30.5
relationship
No. of data
(pgrn-“)
Indoors
i
i A-l A-2
concentrations
Outdoors
No. of data
A-2
of ammonia
r
2.2 -51.9 2.2-53.5
P
-. 0.113 0.2'73
go.05 $0.05
6.7-47.4 4.1-27.6
0.5.36 0.304
> 0.05 > 0.05
2.3-20.2 2.LL21.4
0.085 0.756
90.05 < 0.05
(pgmm3) Indoors
Winter
SW
5.4
2.87
Summer
Winter
SIW
41.9
38.5 50.2
1.09 1.17
44.3
1.32 0.62
58.5
4.2
4.02
14.4
1.31
103
58.5
8.7
2.15
131
9.3
1.45
49.2
167 42.3
56.9
3.10 0.86
to explain unless in summer, owing to opening of the windows, both indoor and outdoor ammonia concentrations were influenced by the same source. The best fit was found at the site with highest indoor concentrations (D). In winter only one site (C) had high concentrations both indoors (> 100pgmm3) and outdoors (up to 49pgmm3). Building C was recently completed when measurements were made and the room surveyed had not yet been in use. The highest CO and
76
@
INDOOR
0
0U1000R
WINTER
t 5 ” g ”
150
a z I” :
100
Al
*2
B
C
0
E
SITE
Fig. 1. Relationship Zagreb.
between
indoor
and outdoor
ammonia
concentrations
by season
at six sites
in
HCHO concentrations were also recorded in this room, suggesting that either cigarette smoke or car exhausts were possibly entering the ventilation system. At other indoor sites NH, concentrations varied between 38.5 and 56.9 pgm ‘, and at sites A-l, A-2, B and E similar levels were also found in summer. Outdoor concentrations were significantly higher in summer than in winter, which is in agreement with the findings of Okita and Kanamori [6] who, in Tokyo air, found a linear correlation between ammonia concentrations and temperature. This suggests that atmospheric ammonia is produced mainly by biological activity. Georgii [7] and Hantzsch and Lahmann [8], in contrast, reported marked maxima of ammonia concentrations in Frankfurt and Berlin air in winter owing to domestic heating. Our preliminary investigations show that indoor ammonia concentrations can reach undesirable levels and that more attention should be paid in future to possible sources.
71 ACKNOWLEDGEMENTS
The authors wish to thank Mr Z. Frkovib, 11. Lipovac for technical assistance.
Mrs K. Pondeljak,
A. Filipec and
REFERENCES B. Berglund, T. Lindvall and J. Sundell (Eds), Proceedings of the Third International Conference on Indoor Air Quality and Climate, Swedish Council for Building Research, Stockholm, Sweden, 1984. J.E. Yocom, Indoor-outdoor air quality relationships. A critical review, J. Air Pollut. Control Assoc., 32 (1982) 506520. U.S. National Research Council, Subcommittee for Ammonia, “Ammonia”, University Park Press, Baltimore, 1979. G. Kunkel, R. Rudolph and R. Muckelmann, Innenraumluft und allergische Erkrankungen, in K. Aurand, B. Seifert and J. Wegner (Eds), Luftqualitat in Innenraumen. Schriftenreihe des Vereins fur Wasser-, Boden- und Lufthygiene, No. 53, Gustav Fischer Verlag. Stuttgart, 1982, pp 7L89. A. Sisovii: and M. FugaL, Application of impregnated filters to determination of smoke and ammonia, Environ. Monit. Assess., in press. T. Okita and S. Kanamori, Determination of trace concentration of ammonia in the atmosphere using pyridine~pyrazolon reagent, Atmos. Environ., 5 (1971) 621627. H.W. Georgii, Oxides of nitrogen and ammonia in the atmosphere, J. Geophys. Res., 68 (1963) 3963-3970; cit. 395 in “Ammonia” (ref. [3]). S. Hantzsch and E. Lahmann, Ammoniak Bestimmungen in Grossstadttluft, Schriftenriehe des Vereins fur Wasser-, Boden- und Lufthygiene, No. 33 (1970) 3539.
INDOOR/OUTDOOR CONCENTRATIONS
ANICA Institute (Received
$IsOVIc,
KRESIMIR
for Medical April
RELATIONSHIP IN SELECTED
22nd.
Research
VEGA and
and
May
llth,
Netherlands
OF AMMONIA OFFICE BUILDINGS
NATASA
Occupational
1986; accepted
73 in The
KALINIC Health,
41001
Zagreb,
POB
291 (Yugoslavia)
1986)
ABSTRACT Ammonia concentrations in air were measured simultaneously outdoors and in six offices of five modern buildings in summer and in winter. The concentrations outdoors were generally low, but significantly higher in summer than in winter. The concentrations indoors exceeded several times those outdoors, but showed no systematic seasonal differences. Concentrations of > lOOpgm-” measured in the most recently constructed buildings indicate that more attention should be paid to the possible indoor sources of ammonia. INTRODUCTION
People in moderate climates spend considerably more time indoors than outdoors, but only recently have measurements of human exposure to air pollutants been more frequently performed indoors [l] rather than outdoors. In an attempt to use earlier data obtained for outdoor measurements for assessing previous exposure indoors, simultaneous measurements indoors and outdoors were performed in order to determine conversion factors. It has been shown that an indoor/outdoor relationship can only be established for those pollutants which are not released indoors, and that the ratio depends on the concentration, infiltration rates and reactivity of the pollutants [2]. Ammonia is an air pollutant and a very important component of the nitrogen cycle. Concentrations outdoors are usually low [3], except in the vicinity of industrial sources, farm houses and agricultural applications. Indoors, ammonia may originate from cleaning agents, metabolic processes, smoking or from external sources. Although ammonia is on the list of chemical irritants which may cause bronchial asthma [4], its presence in indoor environments has been neglected, as it is not considered to be a non-occupational hazard, and therefore is not included in guidelines for indoor air quality. The purpose of our investigation was to undertake a preliminary assessment of ammonia concentrations in a limited number of modern offices, s,ituated in different parts of Zagreb, with different heating and ventilation systems, and t.o establish their relation to the outdoor concentrations.
0048.9697/87/$03.50
1~~‘1987 Elsevier
Science
Publishers
B.V
74 EXPERIMENTAL
Sampling
programme
Simultaneous samples were collected outdoors and within six offices of five buildings over a period of l&12 days at each sampling site, both in the winter and summer of 1983. The buildings were located as follows (the year the building first started to be used is in parentheses): A-l,2 (1973) business quarter adjacent to industrial area (room A-2 has recently been renovated); B (1982) industrial area; C (1983) the city centre; D (1982) business quarter adjacent to industrial area; E (1983) residential area. Buildings A, B, C and D are large office buildings with forced ventilation systems, while building E is smaller and has no forced air ventilation. In building D the windows were sealed, while in other buildings with forced ventilation, some of the windows of each room could be opened. Space heating was provided in building A by air conditioning, in buildings B and C 30% by air conditioning and 70% by a hot water system, while in buildings D and E only by a gas-fired hot water system. Sampling
procedure
Samples were collected on a 5 cm2 area of Whatman No. 1 filter papers at a flow rate of 1.8 dm3 mini’ and with the exposure area impregnated with a solution of oxalic acid in ethanol [5]. The total volume of air sampled over 24 h was recorded by a gasmeter. Analysis
of samples
After samples had been collected the impregnated filters were immersed in 50 cm3 of H,O, solution. To a 9 cm3 aliquot of the extract 1 cm3 of Nessler reagent was added and the absorbance was measured at 440nm. RESULTS
AND
DISCUSSION
The results of measurements are presented in Table 1 for summer and in Table 2 for winter as number of measurements, arithmetic means (X) and range of NH, concentrations measured outdoors (Out) and indoors (In) as well as the In/Out ratios and Spearman correlation coefficients (r) between indoor and outdoor concentrations. The relationship between average winter and summer concentrations outdoors and indoors is shown in Table 3. Ammonia concentrations indoors were systematically several times higher than those outdoors at all sites, both in summer and in winter (Fig. l), which indicates that the source must have been indoors. In some cases, however, there was a significant correlation between indoor and outdoor ammonia concentrations (at sites B, C and D in summer and at site E in winter), which is difficult
IO
TABLE
1
Indoor/outdoor Site
A-l
relationship
10 10
8
12
C D E
12
TABLE
2
10 10
Indoor/outdoor Site
Range
15.5 16.9 18.9 18.7 13.5
8.5 22.0 4.7-27.0
4.2 14.4
B
11 13
n E,
12
8.7
10
9.3
TABLE
3
Seasonal Site
variations
C
D E
Range
x
Range
41.9
26.3-53.0
2.1
2.0~ 5.8
0.31
> 0.05
58.5 58.5
38.G75.7 44.4- 75.4
3.7 3.5
2.34.3
0.04
$0.05
2.1-9.5
0.79
60.2
5.4 6.7
2.s24.9 4.6 20.0
0.86 0.44
< 0.01 < 0.01 < 0.01
3.7
l.M.6
0.55
> 0.05
49.2
of ammonia
15.5 16.9 18.9 18.7 13.5
134.7
83.8~169.1 29.670.8
concentrations Indoors
0.9
X
17.9
0.~9.0 5.3-48.7 2.3 20.7 2.c21.2
in average
ammonia
Range
(agm
“) ~
ratio
x
Range
32.8-48.2 23.764.4
7.1 9.3
44.3 167.0
30.M7.2 128 281
10.5 11.6 4.9 6.1
42.3 56.9
25.7 53.3 42.C77.4
concentrations
r
P
winter
In/Out
38.5 50.2
Outdoors Summer
A-l A-2 B
ratio
7.7-20.9
10
c
In/Out
103.0 131.2
Range
5.4
summer
Z
Outdoors
10
~
3.S25.6 4.2-30.5
relationship
No. of data
(pgrn-“)
Indoors
i
i A-l A-2
concentrations
Outdoors
No. of data
A-2
of ammonia
r
2.2 -51.9 2.2-53.5
P
-. 0.113 0.2'73
go.05 $0.05
6.7-47.4 4.1-27.6
0.5.36 0.304
> 0.05 > 0.05
2.3-20.2 2.LL21.4
0.085 0.756
90.05 < 0.05
(pgmm3) Indoors
Winter
SW
5.4
2.87
Summer
Winter
SIW
41.9
38.5 50.2
1.09 1.17
44.3
1.32 0.62
58.5
4.2
4.02
14.4
1.31
103
58.5
8.7
2.15
131
9.3
1.45
49.2
167 42.3
56.9
3.10 0.86
to explain unless in summer, owing to opening of the windows, both indoor and outdoor ammonia concentrations were influenced by the same source. The best fit was found at the site with highest indoor concentrations (D). In winter only one site (C) had high concentrations both indoors (> 100pgmm3) and outdoors (up to 49pgmm3). Building C was recently completed when measurements were made and the room surveyed had not yet been in use. The highest CO and
76
@
INDOOR
0
0U1000R
WINTER
t 5 ” g ”
150
a z I” :
100
Al
*2
B
C
0
E
SITE
Fig. 1. Relationship Zagreb.
between
indoor
and outdoor
ammonia
concentrations
by season
at six sites
in
HCHO concentrations were also recorded in this room, suggesting that either cigarette smoke or car exhausts were possibly entering the ventilation system. At other indoor sites NH, concentrations varied between 38.5 and 56.9 pgm ‘, and at sites A-l, A-2, B and E similar levels were also found in summer. Outdoor concentrations were significantly higher in summer than in winter, which is in agreement with the findings of Okita and Kanamori [6] who, in Tokyo air, found a linear correlation between ammonia concentrations and temperature. This suggests that atmospheric ammonia is produced mainly by biological activity. Georgii [7] and Hantzsch and Lahmann [8], in contrast, reported marked maxima of ammonia concentrations in Frankfurt and Berlin air in winter owing to domestic heating. Our preliminary investigations show that indoor ammonia concentrations can reach undesirable levels and that more attention should be paid in future to possible sources.
71 ACKNOWLEDGEMENTS
The authors wish to thank Mr Z. Frkovib, 11. Lipovac for technical assistance.
Mrs K. Pondeljak,
A. Filipec and
REFERENCES B. Berglund, T. Lindvall and J. Sundell (Eds), Proceedings of the Third International Conference on Indoor Air Quality and Climate, Swedish Council for Building Research, Stockholm, Sweden, 1984. J.E. Yocom, Indoor-outdoor air quality relationships. A critical review, J. Air Pollut. Control Assoc., 32 (1982) 506520. U.S. National Research Council, Subcommittee for Ammonia, “Ammonia”, University Park Press, Baltimore, 1979. G. Kunkel, R. Rudolph and R. Muckelmann, Innenraumluft und allergische Erkrankungen, in K. Aurand, B. Seifert and J. Wegner (Eds), Luftqualitat in Innenraumen. Schriftenreihe des Vereins fur Wasser-, Boden- und Lufthygiene, No. 53, Gustav Fischer Verlag. Stuttgart, 1982, pp 7L89. A. Sisovii: and M. FugaL, Application of impregnated filters to determination of smoke and ammonia, Environ. Monit. Assess., in press. T. Okita and S. Kanamori, Determination of trace concentration of ammonia in the atmosphere using pyridine~pyrazolon reagent, Atmos. Environ., 5 (1971) 621627. H.W. Georgii, Oxides of nitrogen and ammonia in the atmosphere, J. Geophys. Res., 68 (1963) 3963-3970; cit. 395 in “Ammonia” (ref. [3]). S. Hantzsch and E. Lahmann, Ammoniak Bestimmungen in Grossstadttluft, Schriftenriehe des Vereins fur Wasser-, Boden- und Lufthygiene, No. 33 (1970) 3539.