Asbestos-Containing Materials and Airborne Asbestos Levels in Industrial Buildings in Korea

Recently in Korea, the treatment of asbestos-containing materials (ACM) in building has emerged as one of the most important environmental health issues. This study was conducted to identify the distribution and characteristics of ACM and airborne asbestos concentrations in industrial buildings in Korea. A total of 1285 presumed asbestos-containing material (PACM) samples were collected from 80 workplaces across the nation, and 40% of the PACMs contained more than 1% of asbestos. Overall, 94% of the surveyed workplaces contained ACM. The distribution of ACM did not show a significant difference by region, employment size, or industry. The total ACM area in the buildings surveyed was 436,710 m2. Ceiling tile ACM accounted for 61% (267,093 m2) of the total ACM area, followed by roof ACM (32%), surfacing ACM (6.1%), and thermal system insulation (TSI). In terms of asbestos type, 98% of total ACM was chrysotile, while crocidolite was not detected. A comparison of building material types showed that the material with the highest priority for regular management is ceiling tile, followed by roof, TSI, and surfacing material. The average airborne concentration of asbestos sampled without disturbing in-place ACM was 0.0028 fibers/cc by PCM, with all measurements below the standard of recommendation for indoor air quality in Korea (0.01 fibers/cc).

The distribution of ACM did not show a significant difference by region, employment size, or industry. The total ACM area in the buildings surveyed was 436,710 mZ. Ceiling tile ACM accounted for 61% (267,093 m2) of the total ACM area, fo11owed by roof ACM (32%), surfacing ACM (6.1%), and thermal system insulation (TSD. In terrns of asbestos type, 98% of total ACM was chrysotile, while crocido]ite was not detected. A comparison of building material types showed that the material Introduction Asbestos is the name given to a group of six different fibrous minerals (amosite, chrysotile, crocidolite, tremolite, actinolite, and anthophyllite) that occur naturally in the environment [1].
Asbestos fibers do not dissolve in water or evaporate and are resistant to heat, fire, chemical and biological degradation. Because of these properties, asbestos has been used in a wide range of manufactured goods, including roofing shingles, slate, ceiling and floor tiles, coatings, and friction materials such as brake and transmission parts. Exposure to asbestos can be harinfu1 to human health if asbestos fibers are inhaled into the lungs after being released into the air when asbestos is disturbed or in poor condition. Numerous epidemiological studies have shown that exposure to asbestos may cause asbestosis, lung cancer and mesothelioma of the pleura or the peritoneum [2 '7]. Asbestos has been declared a proven human carcinogen by the U.S. Environmental Protection Agency (EPA) and by the Intemational Agency fOr Research on Cancer (IARC) [8,9] [12].
Most developed countries have banned the use of asbestos products [13][14][15]. wnile use of asbestos materials in developed nations has been decreasing because of the harmfu1 health effects of asbestos, use of those in developing countries is increasing [16]. In 2003, Asian countries accounted fbr nearly 50% of global asbestos consumption [17].
In Korea, asbestos was first recorded as having been mined in the mid-l930s. Asbestos mining stopped completely in the mid-1980s because domestic production could not compete with cheap imports. All asbestos used in Korea was imported since that time [18]. year for the sample, area of distribution, physical characteristics (friability), and damage severity were also investigated.
In this study, the definition of friability was based on the U.S. EPA' s National Emission Standards for Hazardous Air Pollutants (NESHAP), Friable asbestos material means any material containing more than 1% asbestos as determined using polarized light microscopy (PLM), that, when dry, can be crumbled, pulverized, or reduced to powder by hand pressure [25]. S CHol et at If suspect materials were damaged in 10% or more of their surface, they were rated as being in poor condition.
If less than 10% of the surface was damaged it was rated fair, and good condition materials had little or no visible damage or deterioration.

Bulk sampling and analysis
Bulk sampling and analysis was conducted according to the US Asbestos Hazard Emergency Response Act (AHERA) [26].
Although the AHERA recommends increasing the number of samples from homogeneous materia]s correspondingly with the area of distribution, three samples were taken fbr one HSG in this study irrespective of the distribution area, due to cost and time limits. During the building inspection, bulk samples were collected from exposed or accessible presumed asbestos-containing materials (PACMs), and ceiling tiles, roof materials, and TSI were analyzed fbr asbestos.
Samples were sent for analysis to the US-based laboratory and Koreabased laboratory that are being quality controlled under the National Institute for Occupa- Samples detected with more than 196 fOr any one of these 6 types by visual estimation were classified as ACM. Analysis of three samples collected from each homogeneous material took a negative approach (positive stop). When asbestos was detected in the first sample, the remaining samples were not analyzed and this homogeneous material was reported as ACM. In case al1 three samples were found to be negative, the homogeneous material was declared as non-ACM.

Air sampling and anatysis
Air sampling was conducted to determine the airborne fiber concentrations in occupied buildings. Sampling was conducted in areas where ACM was present in fbur different conditions by friability (friable vs non-friable) and damage severity (good vs poor or fair).
The air sampling equipment adhered to the requirements of the NIOSH Method 7400 [28] and AHERA [26]. The air samples were taken by drawing air through mixed cellulose ester filters in sampling cassettes with a 5 cm conductiye cowl.
Normally, sampling pumps were operated at a flow rate of 2-3 tlmin. Each sample volume was kept within the range of 700-2,OOO l with a target of about 1,500 l. The air samples were analyzed using phase contrast microscopy (PCM) according to the NIOSH Method 7400. All fibers meeting the length and aspect ratio criteria (length > 5 pm and length-to-width ratio > 3 tol) were counted in more than 100 fields.  When the darnage of ACM was evaluated, 85.8% of total ACM was in fair condition, 14.2% in good condition and none in poor condition.
indoor asbestos concentrations    The survey showed that 94% of workplaces had ACM (Table 1). Such a distribution rate is higher than the survey result (68%) of buildings in New Yotk City by the US EPA in 1988 [24]. This is due to the fact that more than 90% of the asbestos was used for construction as building materials in Korea. In addition, the import of asbestos-containing products rapidly increased after 1997, and most of the imported products were building materials [19].
The ACM distribution in workplaces did not show a large difference by region; nevertheless, surfacing ACM and TSI showed a significantly low distribution in workplaces in Seoul, Incheon and Jeolla province. This is interpreted as reflecting the difference in employment size in the surveyed workplaces by region. The distribution of smal1-sized workplaces with less than 50 workers, as surveyed in this research, was 2296 and 50% in Seoul, Incheon and Jeolla province, respectively.
It was considered that in such small-sized workplaces with less than 50 workers, HVAC systems and soundproofing tend to be poorly equipped and there are few decorations in the buildings, resulting in a low level of surfacing ACM and TSI ACM.
In terms of the distribution of ACM by business, only ceiling tiles showed a significantly low distribution in the service industry. This could be attributable to the fact that remodeling operations are frequently imptemented for decoration purposes.
In terms of ACM by the type of building material, ceiling tile showed the highest distribu-  [30,31].
Therefbre, buildings built before 2005 have high potential to have ACM.
The asbestos industry in Korea was transferred from Japan, but there are big differences between the two countries in the amounts and peak time of asbestos use, as well as the type of asbestos used predominantly in the two countries: chrysotile in Korea and chrysotile with amosite and crocidolite in Japan [32].
Our results also showed that 97.7% of total ACM was chrysotile, while crocidolite was not detected. Asbestos spraying was rarely used in housing or construction in Korea [32].
In order to identify the priority for ACM management in building materials in workplaces, four characteristics were considered. The first is the ACM distribution by each building material in the workplace, the second is the proportion of each material in the total ACM area in each workplace, the third is the proponion of friable types among ACM by each material, and the last one is the proponion ofACM in local damaged condition by each material.
In view of these four factors, the material with the highest priority for routine management was ceiling tiles, followed by roofs, TSI, and surfacing materials. It cannot be definitely said that the use of asbestos in a building increases the risk of asbes-