For indoor air quality at a newly built apartment before move-in, we monitored formaldehyde and VOCs and assessed human exposure and probabilistic health risk. We selected 801 newly built apartments all over the country. The results of the research on the condition show the mean concentrations of formaldehyde 294 ㎍/㎥, 210(median) 1497㎍/㎥(maximum), benzene 6㎍/㎥, (4 and 92㎍/㎥), toluene 1003㎍/㎥(773 and 5013 ㎍/㎥), ethylbenzene 120㎍/㎥, (62 and 1192㎍/㎥), xylene 287㎍/㎥(138 and 2723㎍/㎥) and styrene 64㎍/㎥, (42 and 531㎍/㎥). Formaldehyde from carcinogen and toluene and xylene from non-carcinogen were assessed the risk for human health. The excess cancer risk of formaldehyde for human beings between carcinogens is per 1.36 of average 1000 persons. This implies that it is over a level per 1.00 of 1000 persons demanding active risk reduction. Hence, we strongly need the active reduction plan and accurate source assumption. Among a variety of factors affecting indoor air quality for householders, closing construction or density of indoor air processing additional interior construction and indoor area, indoor air quality with a variety of districts show significant. The excess cancer risk for human beings of formaldehyde between carcinogens is per 1.36 of average 1000 persons. Non-carcinogen toxicity rate for human-beings with toluene and xylene among non-carcinogens is over HQ 1 from Seoul to local area.

This research was performed with the subject of 111 offices in a chemical plant of Korea. Airborne concentration level of carbon dioxide, carbon monoxide, formaldehyde and total suspended particulates in the office rooms were measured along with temperature and relative humidity. Simultaneously, general characteristics and subjective health symptoms of 500 office workers were investigated through a questionnaire consisting of the five point weighting method : 0 = not at all, 1 = a little bit, 2 = moderately, 3 = quite a bit and 4 = extremely. Results showed that the mean values for temperature and relative humidity in investigated office rooms were 22.2℃ and 34.3%, respectively. The concentrations of formaldehyde, PM10, carbon dioxide and carbon monoxide were 0.17 ppb, 28.8 ㎍/㎥, 0.95 ppm and 424 ppm, respectively. 56.4% of all the workers investigated replied with a sense of fatigue or weariness (mean=2.23), drowsiness or languidness (mean=2.22), sneezing (mean=2.11) and ophthalmia oreye fatigue (mean=2.07). Female workers, non-smokers, non-drinkers, workers who do shift more than nine hours a day, and workers in poor health experienced more subjective symptoms than other workers (p<0.05). Subjective symptoms of office workers were significantly associated with the following items of office characteristics: the purchase date of office equipment, the change of office furniture, the use of paint, smoking in the office, ventilation condition, the use of an individual air-conditioner, the use of a fax machine, the degree of office repair, the proportion of workers per office, the degree of satisfaction in office environment, and the operation hours of the air-conditioner. Also, subjective symptoms were positively correlated with indoor environmental factors such as relative humidity, carbon dioxide level, level of PM10, and formaldehyde (p<0.05). In conclusion, office characteristics and air quality in a chemical plant affected subjective health symptoms of office workers. Thus, in order to improve the health of workers, to enhance work efficiency, and to establish a better office environment, air quality control in office rooms by optimal ventilation, adequately occupied number of workers in one office, and maintenance of office equipment should be fulfilled thoroughly. keywords：Air quality, Subjective health symptom, Formaldehyde, PM10, Carbon monoxide, Carbon dioxide

The deodorization performances of ammonia, acetic acid and acetaldehyde were tested for each of all forty five air cleaners sold in the online shops and department stores. The removal performances of toluene and formaldehyde were also investigated and the results were compared to the deodorization performances for the air cleaners. Filter-type and complex type air cleaners which used activated carbon filters showed superior in odor removal performances to those of ionizer type and wet type air cleaners. Toluene and formaldehyde were readily removed for the most of filter-type and complex type air cleaners. Ionizer air cleaners had little removal ability for the toluene and formaldehyde.

This study was performed to estimate the emission rate of volatile organic compounds (VOCs) and to evaluate the risk level affected by indoor air pollutants (IAPs) in 27 new apartments (prior to residence) in Seoul City from December 2004 to March 2005. The indoor air pollutants investigated in this study include formaldehyde, several aromatic VOCs (benzene, toluene, styrene, xylene, and ethylbenzene). All measurements were made based on the standard method of Ministry of Environment in Korea. The indoor concentration levels for benzene, xylene, toluene, ethylbenzene, styrene, and formaldehyde have significant increase trend 5 hours after closing windows and doors. Levels of air pollutants did not exhibit significant difference between living rooms and bedrooms. The air exchange rates by the concentration decay method using SF6 were 0.37 for low floor, 0.32 for middle floor, and 0.75 for high floor. The emission rate showed the highest level in the middle floor and second one in the low floor, when estimated by the IAQ model for benzene, toluene, ethylbenzene, xylene, styrene, and formaldehyde. Considering the above result, it is suggested that the estimation of emission rate be considered when the new apartment is designed and constructed with respect to construction materials to emit low VOCs. Moreover, the related regulation should be established for IAQ management.

Vehicle drivers are subject to be exposed to high concentrations of airborne pollutants emitted from vehicles on roads. To investigate the indoor air quality of vehicles on roads, black carbon (BC) was measured inside a passenger car commuting between the residential area in southern Seoul and the Korea Institute of Science and Technology (KIST) in northern Seoul using a portable aethalometer. When the vehicular windows were closed, the ventilation mode was set to fresh air mode (or circulation mode) for a total of thirteen runs made during May 2005. When the windows were open, the analysis was made with the system turned off (for twelve runs in October 2005). The BC concentration depended on such parameters as spatial location, time of day, and ventilation mode. The average BC concentration measured on non-express ways was higher than those measured on express ways, inside KIST, and nearby the residential area for most runs. On circulation mode, the average BC concentration was 5.9±1.7 ㎍/㎥ in the afternoon or evening, which was similar to a 24-hr average BC concentration for ambient air at 200 m apart from a road in Seoul. In the case of fresh air mode, the average BC concentrations measured in the morning rush hour, in the afternoon or evening, and after midnight were 22.8±3.4, 15.9±7.7, 3.7 ㎍/㎥, respectively. The average BC concentrations measured with the vehicular window open were 31.9±9.2, 19.4±5.9 ㎍/㎥, respectively in the morning rush hour and in the afternoon or evening. These measured values were higher than those measured with the windows closed. The average BC concentrations inside a passenger car with a fresh mode operation or open-window driving were significantly higher than a 24-hr average BC concentration measured at 200 m apart from a road in Seoul.

This study was performed to investigate indoor air quality and to characterize the concentration of particulate matters followed by human activities in preschool classrooms. Concentrations of PM10, PM2.5, and PM1 were measured every 5-minute intervals by means of a dust monitor adopting the principle of light scattering. Two mini-volume air samplers were used further to measure the I/O concentration ratio of PM10 and to calibrate the dust monitor since the photometric method often exaggerates the mass of fine particles. The calibration factor in the study environment was determined as 0.64. In the preschool classrooms, the ranges of average indoor PM10, PM2.5, and PM1 concentrations were 51.5~117.6, 21.5~98.4, and 16.2~84.5 ㎍/ ㎥, respectively, while that of I/O concentration ratio was 0.8~1.3. Based on correlation analysis among various environmental parameters, PM1 was slightly correlated with humidity (r=0.416, p<0.01). However, outdoor PM10 was strongly related with indoor PM2.5 (r=0.95, p<0.01), with PM1 (r=0.94, p<0.01), and with PM10 (r=0.84, p<0.01). The trend of PM2.5 and PM1 concentrations appeared to be very similar unlike the case of PM10. Since the elevated coarse particle concentration (2.5㎛<dp<10㎛) and the average PM2.5/PM10 ratio were highly dependent on classroom activities, the parameter of PM2.5/PM10 ratio was intensively studied with 7 different indoor activities in the preschool classrooms.

Uncertainty evaluation was performed for the measurement of Volatile Organic Compounds(VOC) in indoor air. The analytical procedure and result were validated by evaluating every uncertainty source related to the measurement method. An easy approach for uncertainty evaluation for indoor VOC measurement was tested using relative standard uncertainty method which is simple in the evaluation of a measurement uncertainty in case of indoor VOC measurement. The measurement uncertainties of toluene, ethylbenzene, m+p-xylene, styrene and o-xylene in indoor air are obtained as less than or close to 10%, and those results were validated by using Gum-workbench uncertainty evaluation program. Based on the evaluation, uncertainties were found to come largely from two major sources, uncertainty related to the concentration of standard Tenax tube which was used for calibration in measurement, and the to air sampling process. This study could be used as a good example in evaluating uncertainties in the measurement of indoor-air VOC at buildings including a newly-built apartment.

The purpose of this study is to optimize an emission test method for building materials and to understand the characteristics of total volatile organic compounds (TVOC) and carbonyl compounds emission from building materials, especially solid-phase building materials, using a small chamber test method. As a result of the evaluation for small chamber system, temperature and humidity was maintained constantly at 24.5℃, 50.2%. The background concentration of total volatile organic compounds and formaldehyde were also controlled below 20 ㎍/㎥ and 0.5 ㎍/㎥, respectively. Air leakage of emission test chamber and the duplicate precision between two emission test chambers were satisfied. As a result of evaluation for sampling and analysis system (such as the breakthrough test), repeatability of response factor, and retention time in GC/MS and HPLC, desorption efficiency, method detection limits were excellent. The concentration of total volatile organic compounds emitted from wallpapers (made of PVC) was higher at 25℃ than at 23℃. Also, the concentration of formaldehyde emitted from floorings made from non-PVC (wood-based) was higher at 25℃ than at 23℃. On the other hand, there was not a significant difference between the concentrations of total volatile organic compounds emission from wallpaper (made of PVC) which was stored for 2 weeks at 25℃ and 4℃ with tight sealing. In conclusion, emission characteristics of TVOC and formaldehyde from solid-phase building materials would be expected to apply to the plan for the management of indoor air quality.