Indoor Air Quality Characteristics Research Articles

Spatial and temporal variation of cooking-emitted particles in distinct zones using scanning mobility particle sizer and a network of low-cost sensors

Exposure to ambient and household fine-particulate matter is identified as a substantial contributor to premature mortality in India, according to the Global Burden of Disease Studies. This study examines the impacts of typical Indian cooking practices on indoor air quality characteristics by monitoring the evolution of fine and ultrafine particle (UFP) concentration in the dining facility of a residential educational institute in India. The monitoring area was spread across the kitchen (zone 1) and the dining hall (zone 2). A combination of validated low-cost PM sensors (LCS), DustTrak8433, and Scanning Mobility Particle Sizer (SMPS) was utilized for real-time data acquisition while using Liquefied Petroleum Gas (LPG) as the cooking fuel. PM2.5 and UFP concentrations were monitored at 1.3 m and 1.8 m from the floor to assess the vertical variation of pollutants during cooking activities, including breakfast, lunch, and dinner, and processes such as preheating, reheating, stir-frying, and deep-frying. It was found that the prolonged cooking durations involved in high-heat cooking methods like stir-frying and deep-frying resulted in a rise in coarser UFP (300–550 nm) and PM2.5, causing a higher exposure to PM and UFP concentration. PM2.5 levels are higher at upper heights during typical cooking processes because of temperature-driven convection currents and hygroscopic growth of particles due to high humidity levels. Air exchange rates (AER) considerably varied by using chimneys and were low during the controlled (closed doors) compared to mixed ventilation (opened doors) conditions. The maximum AER was obtained during lunch (4.3–9.9 h−1) compared to breakfast (-7.8–6.8 h−1) and dinner (0.55–7.9 h−1). The decrement rate of PM2.5 inside zone 1 was highest during lunch (126 µgm−3 h−1), coinciding with the highest AER during mixed ventilation. It is recommended that improving ventilation and better design of the kitchen can reduce the exposure of PM and UFP in commercial and rural area kitchens.

The comparative analysis of the indoor air pollutants in occupied apartments at residential area and industrial area in dubai, united arab emirates

Most of the research on indoor air pollutants in the United Arab Emirates focus on the state before moving in. There are no studies on the evaluation and characteristics of Indoor Air Quality in living conditions. This study aims to obtain primary data by measuring the concentration of indoor hazardous chemical substances in apartment housings with different area characteristics and to identify the external and internal pollutants that affect them. As a methodology, a comparative analysis was conducted between residential (Business Bay) and industrial areas (Ras Al Khor) to investigate the indoor air pollutants level with the comparison of the outdoor environment, elapsed time after construction, finished materials, temperature, relative humidity, renovation, purchase of furniture and electric appliances, built-in closets, and air cleaning methods. The result showed that Benzene (C6H6), Toluene (C7H8), Ethylbenzene (C8H10), Xylene (C8H10), and Styrene (C8H8) were at a stable level. However, in the case of formaldehyde (HCHO), points exceeding or close to the WHO IAQ standard were found, suggesting that long-term attention is required. The differences between residential and industrial areas were marginal in terms of the size of the house, temperature and humidity, and the building materials. It was proven that the emission of indoor air pollutants from building materials lessened under 18 months after construction.

Optimization of in-Vehicle Carbon Dioxide Level in a 5-Seat Car

The air quality in a car’s cabin can be five times worse than that of residential and non-residential buildings, resulting in a variety of health issues, such as headache, sore throat, and nausea, which are all symptoms of in-vehicle air pollution. The monitoring of carbon dioxide, which is one of the principal pollutants in car cabins, is required before regulating it. The current research is focused on the recording of carbon dioxide levels for different levels of human load, air speed, and temperature. A statistical analysis and plots were obtained for recorded responses to determine air quality parameters for a minimum value of carbon dioxide level in a five-seat car cabin. Three algorithms (generalized reduced gradient (GRG), response surface methodology (RSM), and Genetic Algorithm (GA)) were successfully used in a 5-seat car to optimize the in-vehicle carbon dioxide level. The GRG method provided the minimum carbon dioxide level of 471.531 ppm for a one-human load at an air speed of 2 m/s and a temperature of 24 °C. For varying human loads of 2,3,4, and 5, the GRG and GA methods provided carbon dioxide levels of 508.785 ppm, 580.722 ppm, 659.839 ppm and 769.016 ppm, respectively. Comparing all three techniques, the RSM provided carbon dioxide levels of 471.876 ppm, 508.865 ppm, 580.79 ppm, 659.905 ppm, and 769.362 ppm for human loads of 1, 2, 3, 4, and 5, respectively. This study will provide a platform for the researchers working on indoor air quality characteristics to apply soft computing techniques effectively for the evaluation of comfortable healthy environments and for the benefit of the passengers in car cabins.

Development of CO2 Concentration Prediction Tool for Improving Office Indoor Air Quality Considering Economic Cost

Ventilation is becoming increasingly important to improve indoor air quality and prevent the spread of COVID-19. This study analyzed the indoor air quality of office spaces, where occupants remain for extended periods, among multi-use facilities with an increasing need for ventilation system application. A “tool for office space CO2 prediction and indoor air quality improvement recommendation” was developed. The research method was divided into four steps. Step 1: Analysis of indoor air quality characteristics in office spaces was carried out with a questionnaire survey and indoor air quality experiment. Based on the CO2 concentration, which was found to be a problem in the indoor air quality experiment in the office space, Step 2: CO2 concentration prediction tool for office spaces, which requires inputs of regional and spatial factors and architectural and equipment elements, was developed. In Step 3: Development and verification of prediction tool considering economic feasibility, the cost of energy recovery ventilation systems based on the invoices of the energy recovery ventilation manufacturers was analyzed. In Step 4: Energy recovery ventilation proposal and indoor CO2 forecast, Office Space B, which can accommodate up to 15 people, was derived as an example of the proposed tool. As a result of the prediction, the optimal air volume of the energy recovery ventilation was determined according to the “office CO2 prediction and indoor air quality improvement recommendations”. This study introduced simple tools, which can be used by non-experts, that are capable of showing changes in indoor air quality, CO2 concentration and cost according to activities.

Indoor air quality investigation of a badminton hall in humid season through objective and subjective approaches

This study investigated the indoor air quality (IAQ) during humid season in an old badminton hall, to explore the IAQ characteristics of natural ventilated sports buildings for public use. The indoor air parameters (temperature, relative humidity and air velocity) and indoor air pollutants (CO2, TVOC, PM2.5 and PM10) were measured. A subjective approach was carried out through questionnaire survey. 185 valid questionnaires were recovered, and 68.7% of the participants had exercised. Results show that the indoor air qualities obtained through objective and subjective approaches were obviously different. Indoor PM, TVOC and CO2 concentrations were normal, but 37.3% of the participants complained about the building materials' smell and 73.5% of the participants reported obvious sweaty odor. Physical activity might reduce a person's sensitivity to the environment. The participants generally felt warm and hot because of the high relative humidity. Post-exercise participants felt significantly hotter than those who did not exercise, and were generally more receptive to IAQ. The method of Fanger was employed to narrow the gap between subjective and objective approaches with a modified parameter, and to furtherly estimate the ventilation. The present study demonstrates the necessity to combine two approaches together to assess the IAQ in sports buildings.

Development of mathematical model to study the effect of indoor air quality parameters and optimization using response surface methodology

This paper explores opportunities to know about the optimal setting and influencing parameters of Indoor Air Quality characteristics (IAQ) of the air-conditioned car by response surface methodology (RSM). The trials were designed by the design of experiments and performed to cram the result of input parameters i.e human load, fresh air supply, and air velocity, on the Indoor Air Quality parameters i.e Temperature, Relative humidity, Oxygen and carbon dioxide inside the car air-conditioned space. This work traveled around on finding the mathematical model to show a relationship and interactions of IAQ parameters. Also, this work focused on finding the optimum setting controlling parameters by RSM. It recommend that car AC setting position of fresh air supply knob, and Air velocity (blower speed knob) for different human loads. This study be evidence for that the Response Surface methodology (RSM) techniques were suitable for optimizing the IAQ parameters with the minimum number of trials.

A proactive energy-efficient optimal ventilation system using artificial intelligent techniques under outdoor air quality conditions

Passengers are directly or indirectly exposed to fine dust in indoor air of underground subway stations, which greatly affects the comfort and health of the passengers. However, conventional ventilation systems are manually operated, resulting in high energy consumption, and it is hard to consider the dynamic characteristics of indoor air quality due to the complex relationships between the environment of the subway station and climate change-driven outdoor air quality. Therefore, an energy-efficient ventilation optimization system based on deep learning and artificial intelligence (AI)-iterative dynamic programming was developed in this study for proactive environmental and economic maintenance of the underground ventilation system for a subway’s indoor air quality. The deep learning model predicted the next 24 h of the subway’s environmental status, and the AI-iterative dynamic programming searched a piecewise operational policy of ventilation flow rate for the same operational duration. Energy efficiency was improved by 8.68% while maintaining healthy indoor air quality for the passengers. The proactive optimal ventilation system for the platform of a target subway station presented a decrease of 96 tons of CO2 per year to help address climate change and operating expenditure savings of up to $4217 dollars per year.

A study on the indoor air quality characteristics of schools using public facilities measurement methods

A study on the indoor air quality characteristics of schools using public facilities measurement methods

Indoor air quality analysis of residential buildings in northeast China based on field measurements and longtime monitoring

Outdoor air contamination was frequently observed and focused in northeast China in winter when severe cold days are common and understanding dynamic characteristics of indoor air quality in this area is essential for occupants' ventilation strategies. Herein, using spectrophotometric method, GC-MS (Gas Chromatography-Mass Spectrometer) method, TSI DustTrak particle tester and Telaire 7001 CO2 tester, we investigated the concentration change of formaldehyde (HCHO), volatile organic compounds (VOCs), PM2.5 and CO2 of 21 houses for 4 seasons under 2 conditions (airtight and natural ventilation). Moreover, 6 houses were selected to install convenient sensors for longtime monitoring. Outdoor temperature, concentration of PM2.5, residents' opening window behavior, indoor infiltration rate, temperature, relative humidity and the furniture surface area were also recorded for comparison and correlation analysis. According to the detected results, worst indoor conditions were revealed that average concentrations of HCHO (autumn), TVOC (summer), PM2.5 (winter) and CO2 (winter) were 0.094 mg/m3, 0.924 mg/m3, 0.073 mg/m3, and 883 ppm, respectively. Indoor concentration of PM2.5, TVOC and CO2 exceeded the standard limit and they changed with seasonal characteristics. The observed 4 factors have different effects on indoor air quality. Based on this research, it is recommended that outdoor condition be considered while opening and closing window in winter and ventilation be strengthened in summer.

Cooling Performance and Indoor Air Quality Characteristics of an Earth Air Tunnel Cooled Building

Most of the modern air-conditioned buildings have a low fresh air supply to reduce energy consumption. This results in a poor indoor air quality (IAQ) and a 30–200% higher sick building syndrome than that of a naturally ventilated building. Alternatively, energy-efficient and eco-friendly earth air tunnel system (EATS) provides a good IAQ because of the sufficient fresh air supply. This paper presents the cooling performance and IAQ characteristics of a sparsely occupied building supported with an EATS. The building was monitored for the concentration of fine and coarse particulate matter (PM), carbon dioxide (CO2) and carbon monoxide (CO), temperature distribution and relative humidity (RH) in September and October 2012. The average PM10, PM2.5 and PM1 concentrations were 6.77, 6.11 and 3.17 μg/m3 respectively when the EATS was operated. These are marginally higher compared to that when the EATS was not operated. The average indoor CO2 level, air temperature and RH were 418 ppm, 26.5 °C and 58.2% respectively when the EATS was operated. The diurnal indoor CO2 trend relates well with photosynthetic and anthropogenic activities in and around the building. The CO2 and PM concentrations correlate well with indoor air temperature and RH with a time lag.

Modelling of particulate matters distribution inside the multilevel urban classrooms in tropical climate for exposure assessment

The characteristics of indoor air quality (IAQ) parameters such as PM mass (PM10, PM2.5, PM1) and particle number concentrations (PNC), carbon monoxide (CO), carbon dioxide (CO2), temperature (T) and relative humidity (RH) in multilevel urban classrooms of a school in tropical climate were studied. The PNC in the range 0.35–22.5 μm was monitored for 2 days in each classroom during the working hours using environment dust monitor and converted to mass concentrations. The 8hr-mean concentrations of PM10, PM2.5, PM1 mass, CO, CO2, T, and RH inside ground floor (GF) classroom were found to be 942.84 ± 248.49, 61.59 ± 17.19 and 16.13 ± 3.65 μg/m3, 458.86 ± 58.60 ppm, 34.80 ± 0.81 °C, 55.06 ± 4.10%, 0.93 ± 0.43 ppm, respectively. The PM10 mass concentrations were found to decrease by 8.35 and 46.67%, respectively in first and second floor classrooms. Similarly, PM1 and PM2.5 values were increased by 4.60 and 12.99%, respectively in first floor and decreased by 32.35 and 16.61%, respectively in second floor classrooms. The PNC for particles of size 0.3–1 μm were 58.04, 71.24 and 55.47 particles/cm3 for ground floor, first and second floor classrooms, respectively. The PNC of coarse particles were found to decrease with increase in floor heights. The thermal comfort parameters namely; CO2, T, and RH were more or less showing same trend in all the three classrooms. The distribution of PM10, PM2.5 and PM1 mass data in ground and first floor classrooms fitted with lognormal 3-parameter (3-P) distribution while the second floor PM mass data best fitted to the log-logistic 3-parameter (3-P) distribution.

INDOOR MICROBIAL CONTAMINATION AND ITS RELATION TO PHYSICAL INDOOR AIR QUALITY CHARACTERISTICS AT SELECTED LIBRARIES IN PAHANG

Library contains huge collection of books that can undergo biodeterioration process after period of time. Due to this biological reaction, the existence of airborne particulate matters and microbes in the air of the library can be disturbed and elevated, thus can cause health implications to occupants. Therefore, it is an urge to assess and understand the correlation between physical indoor air quality (IAQ) characteristics, airborne pollutants and microbial contaminants in different library settings and locations. This study was carried out at three different libraries, which are Library A (Gambang as suburban area), Library B (Kuantan as urban area) and Library C (Pekan as rural area). The physical IAQ characteristics and particulate matter (PM) monitoring were assessed by using IAQ Meter and DustMate respectively. Surface Air System IAQ (SAS IAQ) was used to collect the airborne microbes. The microbial contamination was further assessed and identified in the laboratory by using API 20E and API 20 Strep while SPSS was used to analyze the relationship of physical IAQ characteristics, airborne pollutants and airborne microbes contaminants. The scientific method protocol and standard reference limits were compared based on Industrial Code of Practise on Indoor Air Quality, 2010 (ICOP, 2010) regulated by the Department of Occupational Safety and Health (DOSH). Respirable PM in Library A and CFU counts in Library A and C exceeded the standard limit with the value of 0.30 mg/m3, 2744 CFU/m3 and 1833 CFU/m3 respectively. Significant differences (p <0.05) between the selected libraries were observed among relative humidity (p=0.001), inhalable PM (p=0.001), thoracic PM (p=0.001), respirable PM (p=0.01), CO2 reading (p=0.001) and CFU counts (p=0.01). This study demonstrated Library C has poor air quality as the reading for CO2 and CFU counts are very high compared with the other two libraries. The bacterial identification findings indicated that Gram positive bacteria were abundant compared to Gram negative bacteria. Aerococcus viridans is the most dominant type of bacteria isolated in all the libraries.

INDOOR MICROBIAL CONTAMINATION THROUGH WATER MIST AEROSOL AT PUBLIC RESTAURANTS

In Malaysia and many other Asian countries, countless number of restaurants are made of open or semi-open air buildings. These restaurants are commonly located beside roads, factories, and construction sites. The foods are often exposed to the air, increasing their tendency to be contaminated due to poor indoor and outdoor air quality. There are very few studies characterising and comparing the levels of indoor air pollutants in restaurants. Other than that, scarce data are available on dining establishments especially in the presence and absence of water mist application system. Due to these reasons, no best practices or guidelines can be developed. Hence, this present study aimed (1) to assess and compare the physical indoor air quality (IAQ) characteristics and airborne pollutants between different types of restaurant settings; (2) to identify microbes isolated in the presence and absence of water mist system; (3) to analyse bacterial counting within and between the different restaurant settings; and (4) to determine the relationship between physical IAQ characteristics and airborne microbial contaminants. Instruments known as Dustmate and VelociCalc® Multi-Function Ventilation Meter 9565 were used to measure the physical IAQ characteristics and airborne particulate matters. On the other hand, Surface Air System Indoor Air Quality (SAS IAQ) was use to seize the microbial contaminants. All the data obtained were compared with the standard reference known as the Industrial Code of Practice on Indoor Air Quality (2010) constructed by the Department of Occupational Safety and Health (DOSH). This study later indicated that the level of indoor PM10 concentrations was influenced by changes of physical IAQ parameters at the two restaurants investigated. As the PM10 increased, the colony forming unit (CFU) counting also increased. Although microbial contaminations were found during both periods of exposure (i.e., in the presence and absence of water mist) at both restaurants, significant relationship between the parameters measured cannot be determined. The bacterial species obtained during the presence and absence of water mist application system for both of the restaurants were also identified. Gemella morbillorum was found as the most dominant species, followed by other species such as Aerococcus viridans, Globicatella sanguinis, Leuconostoc spp., and Proteus penneri.

INDOOR MICROBIAL CONTAMINATION AND ITS RELATION TO PHYSICAL INDOOR AIR QUALITY (IAQ) CHARACTERISTICS AT DIFFERENT LABORATORY CONDITIONS

Laboratory usually refers to a room or building equipped with chemicals and biological agents for scientific experimentation and research. Due to its own indoor hazards and its cause of health implications, it is an urge to assess and to understand the physical indoor air quality (IAQ) characteristics in the laboratory and the variables affecting the degree of exposure to occupants. The main objectives of this study was aimed to assess and to compare the physical IAQ characteristics and airborne pollutants including particulate matters (PM) and gaseous pollutants between laboratories, to identify microbial contaminants via bacterial counts as well as scientific bacterial-kits species identification and to correlate the relationship of physical IAQ characteristics, airborne pollutants and microbial contaminants between different laboratory settings within the same building which are Natural Product (NP) laboratory, Plant Tissue Culture (PTC) laboratory, and Microbiology laboratory. The physical IAQ characteristics and airborne PM was measured using VelociCalc multi-function ventilation meter 9565 and DustMate environmental dust detector respectively. Surface Air System Indoor Air Quality (SAS IAQ) was used to capture the microbial contaminants and after that bacterial counting and identification were done. The scientific method protocol and standard reference limits were compared based on Industrial Code of Practice on Indoor Air Quality (ICOP) (2010) regulated by the Department of Occupational Safety and Health (DOSH). The temperature of PTC laboratory, velocity of NP laboratory and Microbiology laboratory, the respirable particulate matter (PM) of all three laboratories and Colony Forming Unit (CFU) count of PTC and NP laboratory exceeded the standard limit regulated by DOSH. This study demonstrated that Gemella morbillorum is the common bacterial species available in the environment with poor IAQ and there is a significant relationship between physical characteristics, airborne pollutants and microbial contaminants between the different types of laboratory settings. In conclusion, priority should be given to NP laboratory as it is exposed to poor IAQ conditions and immediate action should be taken to eliminate the problems.

Characteristics of indoor air quality at urban elementary schools in Seoul, Korea: Assessment of effect of surrounding environments

The indoor environment of schools where children stay for long periods of time is a matter of primary concern due to the vulnerability and sensibility of children to air pollutant exposure. The aims of this study were to characterize the indoor air quality of elementary schools in Seoul, Korea, to compare the indoor levels according to the surrounding environments and year of remodeling. The air pollutants, including particle matter (PM10), nitrogen dioxide (NO2), carbon monoxide (CO), carbon dioxide (CO2), total bacteria count (TBC), total volatile organic compounds (TVOC) and formaldehyde (HCHO), were sampled during autumn from classrooms and laboratories at 116 elementary schools employing natural ventilation. The schools were selected based on their surrounding environments: surrounded by buildings (SB), roadways (RW), and mountains (MT). The indoor air quality measured at elementary schools in Seoul, Korea showed generally low levels of pollutants due to low occupancy and adequate ventilation and the indoor levels of PM10 and TBC in schools near roadways were significantly lower than other surrounding environments due to dispersion of pollutants, without obstruction by buildings and mountains. TVOC and HCHO concentrations of schools remodeled within a year were significantly higher. Therefore, suitable management for school building characteristics is needed.

FUZZY RULE BASED PREDICTION OF IAQ CHARACTERISTICS IN AIR CONDITIONED CAR

Air conditioning is widely applied for the improvement of standard of living in human life. This present investigation focused on the prediction of indoor air quality characteristics of air conditioned car using fuzzy logic algorithm. The conditioned space was selected and the experiments were planned as per design of experiments to study the effect of human load, fresh air supply and air velocity on the human comfort conditions. The mathematical models were developed to predict the comfort conditions, namely temperature, CO2 level and relative humidity over a specified range of input conditions. Carbon dioxide exhalation rate differs person to person based on their body weight and burning rate of calories, etc. Fuzzy logic predicted the intermediate response of IAQ parameters for varying input conditions in this present investigation. The proposed multi response fuzzy model predicted better results comparing with nonlinear regression models. The absolute error percentage of fuzzy model for carbon dioxide level, temperature and relative humidity is 2.05%, 3.81 % & 2.24 % respectively.

Indoor Air Quality in Urban and Rural Preschools in Upper Silesia, Poland: Particulate Matter and Carbon Dioxide.

Indoor air quality (IAQ) in preschools is an important public health challenge. Particular attention should be paid to younger children, because they are more vulnerable to air pollution than higher grade children and because they spend more time indoors. Among air pollutants, particulate matter (PM) is of the greatest interest mainly due to its acute and chronic effects on children’s health. In addition, carbon dioxide (CO2) levels indicate ventilation conditions. In this paper, we present the concentrations of PM (PM1, PM2.5, PM10 and total—TSP) and CO2 monitored in four naturally ventilated nursery schools located in the area of Gliwice, Poland. The nursery schools were selected to characterize areas with different degrees of urbanization and traffic densities during the winter season. The results indicate the problem of elevated concentrations of PM inside the examined classrooms, as well as that of high levels of CO2 exceeding 1000 ppm in relation to outdoor air. The characteristics of IAQ were significantly different, both in terms of classroom occupation (younger or older children) and of localization (urban or rural). To evaluate the children’s exposure to poor IAQ, indicators based on air quality guidelines were proposed to rank classrooms according to their hazard on the health of children.

Optimization of Indoor Air Quality Characteristics in an Air-Conditioned Car Using Multi-objective Genetic Algorithm

The current investigation is focused on the analysis of indoor air quality characteristics of an air-conditioned car using multi-objective genetic algorithm (MOGA) approach. The conditioned space was selected, and the experiments were planned as per design of experiments to study the effect of human load, fresh air supply and air velocity on the human comfort conditions. The nonlinear regression models were developed to predict the comfort conditions, namely temperature, CO2 level and relative humidity over a specified range of input conditions. The optimum values of indoor air quality responses like Carbon dioxide level below 1,000 ppm, temperature less than 26°C and relative humidity below that of 60% were predicted for input conditions using MOGA in this present investigation.

어린이집 실내공기 중 주요 오염물질의 특성 및 환기에 관한 연구

Abstract As the number of nursery facilities and infants who stay there is continuously increasing, IAQ(Indoor Air Quality)of nursery facilities should be managed strictly and thoroughly because infants are more susceptible to infectionsdue to their low resistivity. In this study the characteristics of IAQ and ventilation associated factors were investigaedfor suggesting a desirable condition for IAQ management. Environmental factors were not much related to IAQcharacteristics rather than internal factors such as structures of the room. And the positive effect of ventilation onIAQ was obvious and seemed to hinge on factors related to window area especially window/wall ratio. Results ofthis study indicate that the structure with broader window area of a room and frequnet ventilation can be an effectiveway for keeping IAQ of nursery facilities clean and safe. Key words : Indoor air quality, Ventilation, Nursery facilities *Corresponding author.Tel : +82-(0)42-870-3374, Email : whitebear@korea.kr

Optimization of IAQ characteristics of an air-conditioned car using GRA and RSM

Considering that air conditioning is widely applied for improving human standard of living, this present investigation is focused on the optimization of indoor air quality characteristics of air-conditioned cars using the Gray relational analysis (GRA) and the response surface methodology (RSM). The air-conditioned space is selected and the experiments are planned as per experimental design to study the effects of human load, fresh air supply, and air velocity on human comfort conditions. Mathematical models are developed to predict the comfort conditions, namely temperature, CO2 level, and relative humidity over a specified range of input conditions. The optimum values of comfort conditions for varying input conditions are found by assigning weightages to individual responses using GRA and RSM.