A NEW INDOOR AIR QUALITY ASSESSMENT SYSTEM AND ITS SOFTWARE TOOL

Transcription

1 A NEW INDOOR AIR QUALITY ASSESSMENT SYSTEM AND ITS SOFTWARE TOOL J Yuan 1*, JH Han, XD Xie and ZY Qi ABSTRACT This article describes the features and operation of a new indoor air quality assessment system and its software tool named SRIBS-IAQ. The assessment system and its software tool were used in a case study to establish its practicality and performance. This assessment system is unique in the sense that it employs an optimization model called the grey model. We establish a set of Air Quality Objectives (AQOs) among which were five compulsive : HCHO TVOC C6H6 NH3 and radon, The others are optional:o3 CO 2 CO NO2 PM10 microbe. It also includes the assessment of comprehensive environmental impacts such as combined toxicity of HCHO and TVOC and the database of Shanghai local meteorology, building materials and construction properties. Based on the different functional building, residence and office, this new indoor air quality assessment system use some scientific models to evaluate the main influence factors and its impact on human health, comfort and productivity in indoor environment, it also to predict the concentration and exposure rules in certain times. And then, in order to reflect the result directly, we use a positive score for this evaluation system. The application of a weighting system of the score was also afforded. Some scientific and reasonable control and improve measurements are put forwarded.index TERMS Indoor air quality Assessment system; Software tool; Grey model; Improve measurements INTRODUCTION On average, we spend more than 70% of our time at homes, in offices and other indoor environment. Good indoor air quality safeguards our health and contributes to our comfort and well-being. It can also improve productivity at the workplace. On the other hand, poor indoor air quality may lead to discomfort, ill health and, in workplace, absenteeism and low productivity. Over the past several decades, our exposure to indoor air pollutants has increased due to factors such as tightly sealed buildings, reduced ventilation rates to save energy, use of synthetic materials and chemically formulated personal care products, pesticides, and other household items. So it s urgent for us to decrease the impact of the indoor air quality on occupants health. While, the indoor air quality is complex and made up of many factors. It is necessary to take various aspects of those factors into consideration. There is a worldwide trend to develop a system that can provide comprehensive assessments of indoor air quality. The government of china is toward this trend. Its suited software tool was put up with, too (Zhang 2002). Description of the methodological structure of IAQ-SRIBS Based on the different functional building, residence and office, integrated assessment systems use some scientific models to evaluate the main influence factors and its impact on human health, comfort and productivity in indoor environment, it also to predict the concentration and exposure rules in certain times.and then,some scientific and reasonable measurement are put forwarded. This section will describe the main methodological based on which IAQ-SRIBS has been developed. Assessment methods have therefore to describe the means for taking these different issues into account and integrating them in an overall approach. The following Fig.1 is hierarchical presentation of the assessment system. 1)Indicators The main factors that affect IAQ are divided into three kinds of pollutants, the Chemical index, since the different functional room, the different its main pollutants. We establish a set of indoor chemical objectives among which were five compulsive: HCHO TVOC C 6 H 6 NH 3 radon. the optional index is :O 3 CO 2 CO NO2 PM10. Secondly, Physical pollutant is established, they are temperature relative humidity(rh) air velocity. Thirdly, biological pollutant: microbe. 2)Evaluation criteria The Ministry of Construction and the China State Quality Supervision Inspection Quarantine Administration * Corresponding author yuanjing0915@sohu.com 2865

2 (SQSIQA) have promulgated and enacted the code for indoor environmental pollution control of civil building engineering (GB ). According to this standard and another standard named GB/T and other countries advanced standards, about fifteen pollutants were divided into three levels. Table 1 is the details. Indoor air quality comprehensive assessment system Indefinite Clustering Method Chemical Objective choice Physical Devided into three level biological Standard function Evaluation model Weight Clustering vector Subject function Questionnaires HCHO and TVOC combined toxicity Pollutant index Physical index chemical index HCHO enthalpy IAQ improvement meeasurement Figure 1. integrated assessment systems chart indicators Table 1. list of fifteen pollutants Evaluation criteria degree First level Second Third level level CO (mg/m 3 ) CO 2 (ppm) SO 2 (mg/m 3 ) NO 2 (mg/m 3 ) Chemical index HCHO(mg/m 3 ) PM10(mg/m 3 ) Radon(Bq/ m 3 ) TVOC(mg/m 3 ) O 3 (mg/m 3 ) NH 3 (mg/m 3 )

3 C 6 H 6 (mg/m 3 ) biological index microbe (CFU/ m 3 ) temperature ( ) physical index RH(%) 30~40 40~50 50~70 air velocity (m/s) 0.15~0.2 <0.2 <0.3 3)assessment module Grey Interrelated Evaluation Methods It is impossible to build models for all uncertain factors with grey system method. Therefore, grey relation analysis is involved in selecting most important factors such as the objects for study. The following is the brief description of the analytical method. Supposing n is the number of the data sequences measured for indoor air evaluation and the reference number of each datum measured in a sequence is m. The data sequences for the whole data base may be described as follows (Wang 1999): r 11 L r 1n R m n = M M = (r ij) rm1 rmn L About fifteen pollutants were chosen as being a representative set from which to evaluate IAQ: HCHO TVOC C6H6 NH3 and radon, The others are optional:o 3 CO 2 CO NO 2 PM 10 microbe. The values for the reference data sequence may be described as follows: R o (k)={ R o (1), R o (2),, R o (n)} (k=1,2,,n) And the data sequences which describe the measured levels of the indoor air pollutants are similarly described as: R i (k)={ R i (1), R i (2),, R i (n)} (i=1,2,,m) In the present study m=5~15. Non-Dimensional Processing Method The concentrations of the pollutants as measured are expressed in terms of several different physical units. Their dimensionless numerical values differ by several orders of magnitude. This is unacceptable for this mathematical method since the differences would unequally weight the contributions of the various pollutants. Therefore, a calculation to remove the effect of dimension has to be done. The method used is to adjust the data sequence indices to the same quantitative magnitude as follows: U j (k)= R i (k)/b j,(j=0,1,...,m;k=1,2,...,n), where Bj is the maximum order of magnitude for any measurement, which should abide by the following conditions: 0 u hj 1; c h= 1 u hj = 1 According to the same mathematical method, we got the standards data sequences as S ih, 2867

4 h=1,2,,c;i=1,2,,n; S n c s11 L s1n = M M = sc1 scn L (s ih) Finally, we calculate the Interrelated Degrees from the following equation(1). As the interrelated degrees W ih directly reflects a strong or weak relationship between the measured and the reference sequence, all W ih may be arranged numerically and so illustrate how close is the correspondence between the measured sequences and the reference sequence. The larger the value of W ih for a series of measurements is compared to the reference value, the worse is the IAQ. 4)Weightings w = m ih uhj (1) sih j= 1 We draw up an inventory of the dose response for acute and chronic inhalation exposure from the US-EPA and WHO databases (Luc Mosqueron), a score between 2 and 4, reflected the evaluation result on the weight of evidence that the substance is a human carcinogen, was attributed to each pollutant. Three chemicals reach the very high score category: formaldehyde, CO, TVOC, benzene. The original weighting is listed in sequencing. Table 2. Ranking of the 9 pollutants weightings analyzed in the EPA ranking method A B C D E Fi Wi A1 A2 A3 B1 B2 C1 C2 D1 D2 D3 E1 E2 1 CO CO NH O HCHO PM TVOC Rn microbe A,B,C,D,E is carcinogenicity index, potential chronic effect. 5)Score of the indicators In order to figure out easily the Evaluation result. Scores are given based on the scoring criteria (Chiang 2002) for each assessment item. These criteria applied to assessments are determined taking into consideration of the level of technical and social standards at the time of assessment. We use three evaluate scores, basis Health score: 0~100, comfort Score: 0~50, Additional Score: 0~14. Total Score: 0~164. Table 3, 4 shows the relationship between the evaluated score and the magnitude. The manner of score evaluation was represented a four scale, divided from the chemical and physical magnitude, and used a set of references as the benchmarks for determining the scores of 40, 60, 80 and 100.Here, the references corresponded to the score 60 were referred to the criteria of the standard adopted widely for human health, recommended values and building codes. 2868

5 Table 3. scale of the evaluated score corresponded to value Health level Comfort level Healthy level Eligibility level Unhealthy level Health Score Table 4. different levels of indoor air enthalpy and dissatisfactions enthalpy(kj/kg) dissatisfactions (%) Comfort Score Introduction of software tool To operate the system, a microsoft delphi-based indoor air quality (IAQ) simulation software package has been developed and has completed. It includes the assessment of comprehensive environmental impacts and the database of Shanghai local meteorology, building materials and construction properties, as shown in Fig.2. This mode control strategies combines the use of round-predict and improve measurements, as shown in Fig.3. The tool is planned for use in assessing buildings of any type or size. Assessments should be carried out at three design stages: the basic design stage, the design development stage and the construction completion stage. It is developing evaluation methods and tools to help specifiers (contracting authorities, project managers, local and regional authorities) and manufacturers in this field. Figure 2. The mainly Assessment Sheet Set up the basic database of meteorological and the building materials Building Predictive assessment Comprehensive Assessment system imput Inspect data Control and improve measurement No Software result Yes/No? Yes stop Figure 3. The process of software tool assessment 2869

6 In the software tool, we also consider building s local cite, the climate and meteorological, basic characteristic description of the building (build age, building scale, building direction, materials of construction, the numbers of the room or office, ventilation system and maintenance, hygienic facility, heating and cooling system, outside environmental condition around the building) and high and the use of environmental design principles. The Assessment Result Sheet mainly displays the result of the assessment of a building using IAQ-SRIBS software tool, as shown in Fig.4. Figure 4. The meteorological Database and the building materials s database and result sheet If the assessment result isn t obey the standard, we will do some improving measurement and assess again until its got a high score, as shown in Fig.5. Figure 5. The Assessment calculations and improve method Sheet CONCLUSION This paper outlines an assessment system and its tool under development that uses data generated by the above assessment system. This assessment system and its tool is designed to provide a fast check of the building s air quality level. The assessment and its tool would be comprehensive and user-friendly for all the users in the preliminary design stages and detailed design and project phases. It has been thoroughly validated with experimental data and successfully compared to international tools. Although this new assessment system and its software tool has it's infancy and it has been slow to find it's way into the mass market, it is becoming an increasingly important tool in the area of comprehensive indoor air quality assessment. 2870

7 ACKNOWLEDGEMENTS This work was supported by the Shanghai Construction and Management Council Grant No. HT M5. REFERENCES Chiang,CM. A study on the comprehensive indicator of indoor environment assessment for occupants health in Taiwan, building and environment37(2002) GB , Code for Indoor Environmental Pollution Control of Civil Building Engineering GB/T , Indoor air quality standard Lee WL. and Chou CK. (2002) on the study of the credit-weighting scale in a building environmental assessment scheme, building and environment37 Luc Mosqueron, Ranking indoor pollutants according to their potential health effect, for action priorities and costs optimization in the french permanent survey on indoor air quality, Health Effect & SBS symptoms 139 Prior J. (1993) Building research establishment environmental assessment method (BREEAM) version 1: New office. Building Research Establishment report SEPAC and Ministry of Health (2002) Indoor Air Quality Standard U.S.GBC LEED Rating Systems 2.0 Wang HQ. Grey Interrelated Evaluation of Indoor Air Quality in Buildings,Indoor + Built Environment 1999,8, Zhang GQ. Research and development of indoor air quality in china. Proceedings: Indoor Air 2002, 1014~