1), Quee Daily indoor and outdoor nitrogen dioxide (NO2) concentration for 30 days were measured in 28 houses with questionnaire of housing characteristics in Brisbane, Australia. Using mass balance equation and regression analysis, penetration factors and source strength factors were calculated. T he penetration factors of 27 houses except one house were between zero and 1, though penetration factor should be between zero and 1 by means of mass balance equation. Relationship between indoor and outdoor concentrations in each 27 house was calculated using regression analysis. According to the obtained linear regression equation, the slope means penetration factor and the intercept means source strength factor. Calculated mean and standard deviation of coefficients of determination (R2) in electric and gas range houses were 0.70 0.13 and 0.57 0.21, respectively. T he source strength factors were more than zero in 27 houses. Mean and standard deviation of slopes in electric and gas range houses were 0.65 0.18 and 0.56 0.12, respectively. Mean and standard deviation of intercepts in electric and gas range houses were 1.49 1.25 and 5.77 3.55, respectively. Air exchange rate and source strength were calculated from penetration factor and source strength factor, respectively. Geometric mean and standard deviation of calculated air exchange rates in 27 houses were 1.1/hr 1.5. Presence of gas range was the most significant factor contributing to indoor NO2 level in house characteristics (p= 0.003). In gas range houses, source strengths ranged from 4.1 to 33.1cm3/hr m3 with a mean 12.7cm3/hr m3 and a standard deviation 9.8. T he source strengths of gas range houses were significantly different from those of electric range houses by t- test (p< 0.001). Key Words : Indoor air quality, Nitrogen dioxide, Mass balance, Air exchange rate, Source strength
I. 90% (indoor air quality) (Levy et al., 1998).,.., (SBS: sick building syndrome) (Wood, 1991).,,,,.,,,. (infiltration), (natural ventilation) (mechanical ventilation) (Esmen, 1985).,.,.,.. (NO2) (Moschanddreas Relwani, 1987).,, (Relwani, 1986).,,. (Spicer, 1989). NO2 SO2. (Yamanka, 1984). NO2,., (kerosene),. NO2 (air exchange rate) (Sexton et al., 1983). NO2 NO2 (WHO, 1987). NO2 (Bauer et al., 1986; Mohensin, 1987). (Brisbane) 30 NO2.. 30 NO2.. 1. NO2,
NO2 1999 4 6 30.. 2. NO2 (passive sampler). (diffusion) (infiltration) NO2. (5 4 1cm) (15g). triethanolamine NO2 (Yanagisawa Nishmura, 1982). (mass transfer coefficient) 0.10cm/sec (Lee et al., 1992), NO2 photospectrometer (Beckman DU 640). (badge case, spacer) Queensland University of Technology. 30 (protocol) (data- logger), 30. 1. (duplicate measurement)., 3m 2m. 1m,,. 3. (mass balance). (Nazaroff Cass, 1986).,,,.,. dc i dt, = IC o + S - IC i - R V Ci= indoor concentration (ppm), Co= outdoor concentration (ppm), I= air exchange rate (1/hr), S= source strength (cm3/hr m3), R= removal rate (cm3/hr), V= volume of the space (m3). (1) (1) (R) (K, hr-1) (VCi). R = K V C i (2) (2) (1), (1). dc i dt = IC o + S - IC i - K C i (3) ( dc i /dt=0 ), (4).
C i = C o I I + K + S I + K (4). (4) (5). C i = ( I I + K ) C o+ S ( I + K ) (5) I/(I+K) A, S/(I+K) B, (5) (6). C i = A C o + B (6) (6) (A) (B). (5), (A) I K 0 0 1. (B) S 0 0.,, (6). 30 Ci Co (6). 1. 30. Queensland University of T echnology. NO2 30 2 28 (T able 1). 3.4, 3.4. ( 10 ) (plaster: 11 ). 12, Pilot light (Spengler et al., 1994). 30 64%,. 93%. 2. (duplicate measurement) T able 1. House characteristics in 28 houses House type (single detached house) Number of bedroom (=1 or 2) Attached garage Smoker Gas range Gas water heater Window open Number of house with the house characteristic 21 7 17 2 16 8 26 Number of house without the house characteristic 7 21 11 26 12 20 2
.. NO2 8.5%. 7.1% 11.3%. 3. 28 NO2 30 12.6ppb, 8.2. 0.2 60.2ppb. NO2 30 15.5ppb, 8.5. 0.1 58.8. 0.85, 0.41 (T able 2). NO2,,, (Spengler et al., 1994). NO2 (T able 3). NO2 17.0ppb, NO2 9.6ppb. NO2 0.7 0.3 0.9 0.3. 4., NO2. (6). 28 1 0 1., 28 0., T able 2. Mean and standard deviation of NO2 concentrations, and ratio of indoor to outdoor concentration for 30 days in total 28 houses Mean (ppb) Standard deviation Minimum Maximum Indoor 12.66 8.26 0.26 60.26 Outdoor 15.56 8.56 0.16 58.86 Indoor/outdoor ratio 0.85 0.41 0.15 64.06 T able 3. House characteristic associated with indoor NO2 concentration Mean indoor NO2 with characteristics (ppb) Mean indoor NO2 without characteristics (ppb) p- value Gas range 17.0 7.4 9.6 4.5 0.003 Attached garage 16.1 8.9 10.6 4.3 0.038 Gas water heater 16.8 8.0 11.1 5.9 0.047
. 0.65 0.18 0.56 0.12. 1.49 1.25 5.77 3.55. (A: ) (B: ) Fig. 1., 0 1 1 27 30 NO2. (R2) 0.70 0.13 0.57 0.21. Fig. 2. Figure 1. Relationship between penetration factor and source strength factor. Figure 2. Relationship between coefficient of determination and source strength.
5. 27 (5) (6). (5) K 0.8/hr (Wikes et al., 1996; Wade III et al., 1975; Ryan et al., 1983; T raynor et al., 1982). (5) 27 30 1.1/hr 1.5. 27 Lognormal (Wilson et al., 1996). 30 NO2 6.9cm3/hr m3 8.1., NO2 12.7cm3/hr m3, 9.8. 2.8cm3/hr m3, 2.6 (T able 4). NO2 (p< 0.001).. (Brisbane) 30 NO2 (Boston) (Ryan et al., 1988). (autoregression)., NO2. (Levy et al., 1998), 93%. NO2. NO2., NO2. Sexton (1983) NO2 NO2 60% 40%. NO2 65% 56%.,. (Fig. 2). Fig. 2,.,.. T able 4. Calculated source strengths for 30 days in each electric and gas range house Mean (cm3/hr m3) Standard deviation Minimum Maximum Electronic (16 houses) 2.8 2.6 0.3 9.6 Gas (11 houses) 12.7 9.8 4.1 33.1
(5) K( ). K, I K @Risk (Monte Carlo) (Smith, 1994)., I 0.5ACH 3ACH, K 0.8/h 3/h., K (5) I.,, NO2 0.8/hr. NO2,.. (5), 0 1 0. 1 27., NO2,.. V. 28 30 NO2.,,,.,.,, NO2.. 1. (duplicate measurement). NO2 8.5%. 7.1% 11.3% 2. 28 NO2 30 12.6ppb, 8.2. 0.2 60.2ppb. NO2 30 15.5ppb, 8.5. 0.1 58.8ppb. 0.85, 0.41 3. NO2 (p=0.003). NO2 17.0ppb, 9.6ppb. 4. (R2).,. 5.,. 0 1, 0. 27 0 1. 28 0.,
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