SURVEY OF CHEMICALS EMISSION FACTORS FROM BUILDING MATERIALS FOR INTERIORS

Transcription

1 SURVEY OF CHEMICALS EMISSION FACTORS FROM BUILDING MATERIALS FOR INTERIORS Hitomi Yoshida Japan Testing Center for Construction Materials, Japan Abstract Indoor air pollution in buildings is caused by desorption of chemical contaminants from construction materials, such as building boards etc. The healthy indoor environments is closely related to the desorption of chemical contaminants. Desorption of chemical contaminants from building materials is estimated as an emission factor of chemical substances. The JIS relevance articles used for the present building material (mainly used as interior material) were set as the main target of this measurement. Measurement was performed according to JIS A 191 (Determination of the emission of volatile organic compounds and aldehydes for building products --- Small chamber method). Measurement samples are 19 items and 55 kinds. As a result of measuring many kinds of the building materials, we were able to mention the tendency of detected chemical substance and the point which should be inquired from now on. If TVOC is treated as another, formaldehyde is the chemical substance detected by the highest frequency, and toluene is the next. 1. Introduction In order to protect a occupant's health, it is necessary to prevent indoor air pollution. Reduction of the emission factor of a contaminant from building materials for interiors is significant issue that needs to be addressed for occupants. Thus, the emission factor of chemical substance for each material should be measured in order to ensure healthy indoor environments. For this purpose, since the broad data about building materials for interiors was needed, measurements covering many kinds of materials were performed. 2. Principle-----JIS A 191 (Determination of the emission of volatile organic compounds and aldehydes for building products --- Small chamber method) JIS A 191 (Determination of the emission of volatile organic compounds and aldehydes for building products --- Small chamber method) 1) was enacted in January, 3. It has specified small chamber method. Small chamber method is the methods for measuring the carbonyl compounds and VOC emitted from samples. Purified and humidified air is ventilated to

2 stainless steel or glass chamber, and test specimens are installed in the chamber. By analyzing the exhaust air of chamber exit, the chemical substance emitted from test specimen is measured. 3. Small-Scale Chamber ADPAC In this measurements, L size small chamber ADPAC was used. ADPAC (ADvanced Pollution and Air quality Chamber) is small chamber system based on the JIS standard. Main chamber is a product made from stainless steel, and air tightness of chamber is maintained by using teflon packing. When sample installation in chamber, in order to only the sample surface is exposed, seal boxes are usually used. Seal box is a product made from stainless steel with teflon packing. Exposed area of one seal box is about.22m 2 /m 3, and surface area is set to.44m 2 /m 3 by using two seal boxes. It means that loading factor 2.2m 2 /m 3. Figures 1 and 2 show ADPAC system and seal boxes. Figure 1: ADPAC System L Figure 2: Seal Boxes 4. Experimental Procedure 4.1 Sampling The -liter small chamber was installed in a climate chamber with 28 C in temperature. Ventilation in small chamber is performed with the air which passed air cleaning unit and was adjusted to 5% of relative humidity. Exhaust air Sampler (DNPH or Tenax) Sampling Pump Sm allc ham ber (T est specimen installed inside) Mixture Device Clean air Air cleaning unit Indoor air Climate Chamber (28 ) Air Control Unit Pump(for ventilation) Humidifier Silica gel Activated carbon Figure 3: Schematic Diagram of Small Chamber ADPAC System In order to obtain an analysis sample, the air in small chamber was sampled using sampler. It is 1, 3 and 7 days after that the sampling of an analysis sample was performed, after installing the test specimen. Also, in order to check blank value, the analysis sample was sampled before

3 installing the test specimen in small chamber. The sampling of an analysis sample is a total of 4 times. Figure 3 shows the outline of ADPAC System ( liters), the operating condition is shown in Table 1. Another sampler and the analysis method are used for chemical substance measured. Sampling condition for analysis is shown in Table 2. Table 1: Operating conditions of chamber Temperature 28±1 C Humidity 5±5% Air change rate.5 time/h Loading factor* 2.2m 2 /m 3 Internal volume liters * : Loading factor may be changed by the sample (adhesive etc.). Table 2: Sampling conditions Subject to be measured Formaldehyde, acetaldehyde Sampler Sep-Pak DNPH-Silica (Waters Co. made) Flow rate (lit./min) Sampling volume* (lit.) VOC (7 substances) Tenax TA TVOC (SUPELCO Co., made) * : According to samples, sampling volume is adjusted suitably. 4.2 Analysis of Carbonyl Compounds Carbonyl compounds of low boiling point, such as formaldehyde and acetaldehyde etc.were analyzed by HPLC (High Performance Liquid Chromatograph). Carbonyl compounds in air are trapped samplers filled with DNPH(2,4-Dinitrophenylhydrazine). During sampling, carbonyl compounds react with DNPH (derivatization reaction), they change stable hydrazone derivatives. The derivatiation reaction is shown Figure 4. The derivatives are later eluted by acetonitrile and analyzed by HPLC. The analysis condition is shown Table 3. R R C O + NH 2 HN NO 2 [H + ] R C N HN R NO 2 + H 2 O Carbonyl C om pound NO 2 2,4-D initrophenylhydrazine (D N P H ) NO 2 DNPH Derivative (a hydrazone) Figure 4: Derivatization Reaction

4 Table 3: Analysis conditions for formaldehyde and acetaldehyde (HPLC) Apparatus Shimadzu High-Performance Liquid Chromatography LC-VP System (Shimadzu made) Wavelength for detection 3nm Column ZORBAX Bonus-RP (φ4.6 x 15mm) Movile phase Water : Acetonitrile = 52 : 48 Column flowrate Column temperature C 1.5 ml/min 4.3 Analysis of VOC VOC is adsorbed by Tenax, and analyzed by thermal desorption unit and GC/MS (Gas Chromatograph and Mass Spectrometer). Tenax tube is heated by thermal desorption unit, and VOC are desorbed from Tenax. After desorption, VOC is analyzed by GC/MS. The analysis condition is shown in Tables 4 and 5. In the chromatogram obtained from GC/MS, the peak areas between hexane and hexadecane without peak that has an area less than 1ng of toluene are integrated. And from the sum of peak area, TVOC are calculated by using conversion factor for toluene. Table 4: Analysis conditions for VOC (Thermal desorption unit) Conditions for sampler Conditions for trap tube Desorption temperature 25 C Trap temperature 1 C Desorption flowrate 3mL/min. Desorption temperature 25 C Desorption time 5 min. Desorption time 1 min. Inlet split flowrate 5mL/min. Outlet split flowrate 1mL/min. (Note) ATD (Parkin Elmer Co., made) was used for the thermal desorption unit. Table 5: Analysis conditions for VOC (GC/MS) Gaschromatograph SHIMADZU GC-17A GAS CHROMATOGRAPH (Shimadzu made) Column RTX-1 m,.25mmid, 1.4μm df Temperature C (3 min) - (1 C/min) - 2 C (15 min) Mass spectrometer SHIMADZU GAS CHROMATOGRAPH MASS SPECTROMETER GC-MS QP 55A (Shimadzu made) Mode Scan Mass range Emission Factor Emission factor is the quantity of the chemical substance per unit time emitted from the sample. In these measurements, emission factor per unit area was used. A unit is shown by µg/m 2 h. In the case, emission factor per unit length, emission factor per unit volume and emission factor per unit are also defined. From the measured values (concentration of chemical compounds in the chamber) obtained in 4.2, the emission factor was calculated using following formula. EF = n L C t C tb, t

5 where, EF:emission factor (µg/m 2 h) n:air change rate (time/h) L:loading factor (m 2 /m 3 ) C t :concentration of chemical substance in the small chamber at time elapsed t (µg/m 3 ) C tb,t :concentration of travel blank at time elapsed t (µg/m 3 ) 5. Measurements Measurements were performed according to the above-mentioned method, JIS A 191. Subjects to be determined were 1 substances such as formaldehyde, acetaldehyde, 7 kinds of volatile organic compounds (VOC); toluene, xylene, p-dichlorobenzene, ethylbenzene, styrene, tetradecane, nonanal, and TVOC (total volatile organic compounds). 5.1 Test Samples The sample was mainly chosen from the JIS article. Measurement samples are 19 items and 55 kinds. The list of kinds etc. is shown in Table 6. The boards for building materials for interiors, insulations, and adhesives applicable to A and K of Japanese Industrial Standards were chosen as the sample. Almost all samples were on the market. Samples were sealed within one week after manufacturing, and sent to our laboratory. 6. Results Samples were classified into 9 groups according to mainly series. Figure 5 shows maximum and minimum values of emission factors of 7th day were showed for every series. 6.1 Wood Series Fiberboard and particle board fall into this group. In Figure 5, this group is showed as W. S.. In this group, formaldehyde, acetaldhyde and TVOC were detected. And, in the TVOC value, terpenes (α-pinene etc.) showed the high rate. Emission factors of formaldehyde and acetaldehyde decreased a little. 6.2 Cement Series Cement bonded wood-wool and flake boards and fiber reinforced cement boards fall into this group. In Figure 5, this group is showed as C. S.. In this group, acetaldehyde, toluene, TVOC and so on were detected. And there were some samples of cement bonded wood-wool and flake boards whose emission factors of acetaldehyde increased. 6.3 Gypsum series Gypsum boards and floorscreed(gypsum type) fall into this group. In Figure 5, this group is showed as G. S.. In this group, formaldehyde and a small amount of TVOC were detected.

6 Table 6: Samples Name JIS No. Kinds Remarks Adhesives for resilient floorcoverings and woody floorings JIS A Remark 1 Adhesives for wall and ceiling boards JIS A Remark 1 One of the two is LD.5m 2 /m 3 Adhesives for wallpaper and wallcoverings for decorative finish JIS A Remark 2 Cellulose fiber JIS A Remark 3 Cement bonded wood-wool and flake boards JIS A 54 4 Remark 4 Fiberboard JIS A Fiber reinforced cement boards JIS A Floorcovering-PVC JIS A Floorscreeds Remark 5 Glass wool JIS A Remark 4 Gypsum boards JIS A Hard urethane foam JIS A Remark 4 Particle board JIS A Phenol foam JIS A Remark 4(One of the two) Plastic films vapour barrier for residential use JIS A Remark 4 Rock wool JIS A Remark 4 Rock wool sheathing boards JIS A Sealants for sealing and glazing in buildings JIS A Remark 6 Wallpaper JIS A Remark 1: It measured according to JIS scheme(at the time of measurement). Adhesive was painted on stainless steel board (3g/m 2, *mm), and was cured in room of 23 5%, min. LD is.4m 2 /m 3. Remark 2: Adhesives were painted on glass board (13g/m 2, 165*165mm), and were cured in %, 24hrs. Seal boxes were used, LD is 2.2m 2 /m 3. Remark 3: Custom-designed seal box used. It filled with sample(standard construction density, 55kg/m 3 ). Loading factor(ld) is 2.2m 2 /m 3. Remark 4: Seal boxes weren t used. Whole surface of samples were exposed. Remark 5: The test specimen was produced according to specifications, and was cured in room of %, 24hrs. Seal boxes weren t used. Whole surface of sample was exposed. LD is 2.2m 2 /m 3. Remark 6: LD is.425m 2 /m 3. The 5 molds of slump test were used as seal boxes. 6.4 Insulations Cellulose fiber, glass wool, hard urethane foam, phenol foam, rock wool and rock wool sheathing boards fall into this group. In Figure 5, this group is showed as I. In this group,, formaldehyde ajnd a small amount of TVOC were detected. 6.5 Floorcovering-PVC Floorcovering-PVC fall into this group. In Figure 5, this group is showed as F. In this group, toluene, tetradecane, large amount of TVOC were detected. And, in the TVOC value, dodecane and undecane showed the high rate.

7 6.6 Wallpapers Wallpaper fall into this group. In Figure5, this group is showed as W. Vinyl wallpaper showed high emission factors of TVOC. Similarly floorcovering, in this TVOC value, dodecane and undecane showed the high rate. 6.7 Adhesives 3 adhesives fall into this group. In Figure 5, this group is showed as A. One of adhesives for resilient floorcoverings and woody floorings emitted very large amount of tetradecane and TVOC. In this time, chemical substance was not detected during the measurement from one of adhesives for wallpaper and wallcoverings for decorative finish. It is only this one that nothing was detected all chemical substances. Table 7 Detected Cases (55 samples) Whole term Chemical substance Detected cases Detected cases (µg/m 2 h) Emission Factor of 7th day (µg/m 2 h) Formaldehyde Fiberboard Acetaldehyde Toluene Sample that showed maximum value Cement bonded woodwool and flake boards Fiber reinforced cement boards Xylene Floorcovering-PVC p-dichlorobenzene Ethylbenzene Floorcovering-PVC Styrene Fiber reinforced cement boards Tetradecane Adhesives for resilient floorcoverings and woody floorings Nonanal Particle board TVOC Adhesives for resilient floorcoverings and woody floorings If TVOC is treated as another, acetaldehyde is the chemical substance detected by the highest frequency, and toluene is the next. Acetaldehyde was mainly detected from woody sample and cement sample. Toluene was detected from the sample of many varieties. And, p- dichlorobenzene was not detected in all samples which the results were obtained. The TVOC value of three samples was under detectation limit. The three samples were one of adhesives for wallpaper and wallcoverings for decorative finish and two phenol foams.

8 Formaldehyde Ethylbenzene Acetaldehyde 143 Stylene Toluene Tetradecane 6 Xylene Nonanal p-dichlorobenzene 5 3 TVOC 23 Figure 5: Measurements Results

9 6.8 Others Plastic film vapour barrier for residential use and sealants for sealing and glazing in buildings were not showed in Figure 5. Because the former was low value, and the latter were samples whose measurements became impossible (Since too much a lot of VOC were emitted from sealants, HPLC and GC/MS could not analyzed). 6.9 Detected chemical substance The measurement chemical substance and the number of detection cases are shown in Table 7. There was a value at least one sampling, the numbers of detected cases of whole term was counted. With about 3 percent of the sample, the emission factors decreased under to detection limit during the measurement. 7. Afterword In this paper, measurement results of investigation research etc. are summarized. References [1] JIS A 191 (Determination of the emission of volatile organic compounds and aldehydes for building products --- Small chamber method)

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