Malaysian Climate Research Articles

Sleep quality and thermal comfort assessment in the hot and humid climate of Malaysia

ABSTRACT This study examines the relationship between thermal comfort and sleep quality among 417 Malaysian adults via an online survey conducted from November 2019 to April 2020. Participants provided demographic information, thermal comfort, and sleep quality data. The research explores how factors such as air conditioning and pre-sleep behaviours influence individuals’ perceptions of thermal comfort and sleep quality. Findings reveal that thermal sensations change during sleep, with respondents reporting a 50% decrease in warmer sensations upon waking compared to before sleep, and a nearly threefold increase in preference for warmer conditions. Sleep quality responses indicate high levels of calmness and satisfaction, with minimal awakenings at an average of 0.9. Air conditioning, available to 60% of respondents, showed limited improvement in perceived sleep quality, with more air-conditioned individuals reporting night awakenings (68%) compared to those without (53%). Pre-sleep behaviours, such as consuming drinks, were associated with lower thermal sensation upon waking, suggesting a potential cooling effect, while taking a shower before sleep correlated with increased overall comfort, potentially enhancing the sleep experience.

Electrical Performance and Degradation Analysis of Field-Aged PV Modules in Tropical Climates: A Comparative Experimental Study

Performance degradation is a prevalent phenomenon in solar photovoltaic systems globally, with varying aging profiles and effects depending on environmental and climatic conditions. This paper presents an extensive investigation of the electrical performance, aging mechanisms, and degradation analysis of field-aged PV modules under the tropical climate of Malaysia. Utilizing a combination of visual inspection, I-V curve measurement, and thermal imaging techniques, this research provides a comprehensive assessment of the electrical and thermal properties of field-aged PV modules from two locations in Malaysia over extended periods (8 years at UMPSA and 10 years at Pasir Mas). The multi-faceted approach of the study allows for a deeper understanding of the degradation process, offering insights into the causes and effects of higher current and lower voltage in aged modules. The study found the average annual degradation rates at UMPSA were 0.3% for open circuit voltage (Voc), 0.23% for short circuit current (Isc), 0.81% for maximum power (Pmax), and 0.35% for fill factor (FF) and at Pasir Mas, the average annual degradation rates were 1.124% for Voc, −0.166% for Isc, 1.276% for Pmax, and 0.43% for FF. The study also found that monocrystalline silicon (m-Si) panels experienced an average power degradation of 6.48%, while polycrystalline silicon (p-Si) panels showed a higher degradation of 12.76%. However, Thermal imaging revealed significant temperature variations across the modules, with hotspots reaching up to 11.2 °C above cooler areas in UMPSA panels and an even more pronounced 26.1 °C difference in Pasir Mas modules. These temperature disparities highlight the uneven heat distribution and potential performance issues in the panels. This research contributes to the understanding of PV module degradation in tropical climates and aligns with sustainable development, climate change mitigation efforts, and SDG 7 by promoting sustainable energy solutions.

Performance Evaluation of a Triangular-Prism Solar Still using Bagasse as a Porous Medium in the Malaysian Climate

Performance Evaluation of a Triangular-Prism Solar Still using Bagasse as a Porous Medium in the Malaysian Climate

Development and validation of an oil palm model for a wide range of planting densities and soil textures in Malaysian growing conditions

A semi-mechanistic oil palm growth and yield model called Sawit.jl was developed to account for a wide range of planting densities and soil textures under Malaysia's climate conditions. The model comprises components related to meteorology, photosynthesis, energy balance, soil water content, and crop growth. The model simulates instantaneous meteorological properties using daily weather data, calculates simultaneous evaporation from crop and soil with the Shuttleworth-Wallace model, determines soil water content through Darcy's law, and adapts a biochemical C3 model for photosynthesis. The model is also parameterized using updated measurements from the newer tenera oil palm, including temperature-dependent Rubisco kinetics, specific leaf area, and the partitioning of nutrients and dry matter between various tree parts. Sawit.jl was validated using historical field measurement data from seven Malaysian oil palm sites, encompassing palm ages spanning 1–23 years. These seven sites differed in soil type (Inceptisols and Ultisols), planting density (82–299 palms ha−1), soil texture (27–59 % clay and 7–67 % sand), and rainfall (1800–2800 mm yr−1). The model showed overall good accuracy in simulating oil palm parameters (except for trunk weight) across diverse conditions, with model agreement metrics ranging from 6 to 27 % for model absolute errors, −22 to +17 % for model bias, and 0.38 to 0.98 for the Kling-Gupta Efficiency index. The model also predicted the response of oil palm yield to abrupt rainfall changes, such as those during El Niño and La Niña events, while accounting for how soil texture, rainfall, and other meteorological factors influence water deficits and crop photosynthesis. However, model accuracy varied by site, planting density, and oil palm parameter. Model accuracy can be increased by more accurately representing the oil palm microclimate, incorporating fruiting activity, and refining the dry matter partitioning mechanism for the trunk.

LIFECYCLE MAINTENANCE PRACTICES OF VERTICAL GREENERY SYSTEMS IN TROPICAL CLIMATES: A CASE STUDY OF KUALA LUMPUR

ABSTRACT A vertical green system (VGS) proposes numerous benefits, expanding from the principles of sustainable social, environmental and economic development, such as aesthetics, health and ecology. While extensive research exists on VGS in terms of benefits, application, plant selection and design, limited attention has been given to the operational and long-term lifecycle maintenance of VGS, particularly in tropical climates such as Malaysia. Therefore, this paper aims to explore current VGS maintenance practices and issues in the tropical climate of Malaysia. Qualitative analysis was employed to study maintenance practices in commercial and institutional buildings in Malaysia. The qualitative data was then compared with international green wall guidelines to benchmark with current maintenance practices in Malaysia. The study revealed that the absence of a green wall guideline in Malaysia has resulted in a reliance on a limited number of competent experts on green walls, potentially contributing to higher installation and maintenance costs. These findings provide valuable insights into the impact of national guidelines on green wall maintenance practices in Malaysia, assisting building managers and policymakers in formulating appropriate maintenance practices and guidelines.

The Assessment of Thermal Comfort Performance in Bamboo Ecotourism Infrastructure in the Tropical Climate of Malaysia

Ecotourism has become a growing trend, offering a platform for raising awareness of environmental issues in the tourism industry. One of the principles of ecotourism is relying on environmentally friendly infrastructure to prevent environmental degradation. The shift towards ecotourism has highlighted the significance of sustainable practice and infrastructure design in tourism. Bamboo is gradually renowned due to its role in carbon sequestration, bringing hope to the natural environment despite the slow acceptance by society. Assessing the thermal comfort performance takes on added value in the context of encouraging bamboo utilization for sustainable practice. As bamboo gains recognition for its potential in environmental protection, its thermal comfort attributes could encourage its adoption in future infrastructure. Hence, this study examines the thermal comfort performance in bamboo buildings in Malaysia using various design approaches in the same microclimate. Fieldwork was conducted to analyze the indoor and outdoor temperatures in three different chalets in Tadom Hill Resort, Banting, namely Gendui Chalet, Semantan Chalet, and Hakka Village. Generally, findings concluded that the indoor temperatures are higher than the indoor thermal conditions indicated in Malaysia Standard, MS1525:2007. Findings also indicate that the maximum temperature reduction is 2.4°C, 4.1°C, and 4.6°C for Gendui Chalet, Semantan Chalet, and Hakka Village, respectively. Ultimately, this study seeks to emphasize the feasibility of bamboo as a likely option for building construction, developing, and improving the ecotourism destinations in Malaysia.

Endocrine Disrupting Compounds in the Tropical Climate of Malaysia: Pollution, Effects, and Management Strategies

Endocrine Disrupting Compounds in the Tropical Climate of Malaysia: Pollution, Effects, and Management Strategies

Climate Governance and multilevel policy practices in Thailand and Malaysia

Objectives: This paper investigates Thailand and Malaysia climate governance policy in practice within their multi-level governance structures. Thailand presents a unique case of a unitary state with a degree of deconcentration and decentralization, while Malaysia showcases a federal state with a high degree of centralization. Methodology: The paper collected and analyzed both primary and secondary data. In-depth interviews with government officials, NGOs, and international organizations were conducted online and onsite in Thailand and Malaysia from May 2022 to September 2023. Interview data was triangulated with secondary data from key national policy documents on climate change and related issues. This paper examines the contributions and hindrances of multi-level governance on climate governance and highlights some lessons learned from both countries. Results: It concludes that multi-level government systems provide opportunities for various stakeholders to engage in decision-making and create policy innovation. However, the administration of decision-making in these systems can be constrained by tensions within these systems, between tendencies towards the centralization of decision-making, and little engagement between subnational governments and local-level stakeholders. Conclusions: Overall, we assert that clear direction and guidance at the national level complemented by mechanisms that engage local stakeholders in administration and civil society is essential to achieve overarching climate action goals regardless of the administrative system.

From Double Skin Facade to Closed Cavity Façade with Triple Glazed Unite as Inner Skin Without Coatings in the Tropical Climate of Malaysia

The Close Cavity Façade (CCF) has undergone significant advancements from its predecessor, the Double Skin Façade (DSF), resulting in improved thermal insulation and reduced solar penetration. The core principle behind a CCF is a hermetically sealed and non-ventilated construction that incorporates an automatic shading system, triple glazing (TGU) on the inner surface, and single glass on the outer surface. The technique described above effectively regulates the ingress of solar energy and natural light into the building. The experimentation involved the utilisation of various combinations of CCF-TGU designs, employing software tools such as Window 7.8, EnergyPlus, and DesignBuilder. Then, a comparison analysis was undertaken to compare the aforementioned designs with the presently employed single-glazed units (SGU) featuring a grey coating. The inquiry was initiated through the implementation of a case study carried out on a condominium located on Penang Island, Malaysia. The CCF-TGU has superior thermal performance and provides enhanced occupant comfort when compared to SGUs. The effectiveness of CCF-TGU designs in reducing operating temperature ratios has been observed to be higher in Malaysia's humid tropical climate than that of SGUs. The annual rate of decrease varies between 29.8% and 77.8%, thereby successfully attaining the required level of thermal comfort. The research highlights the potential advantages of implementing an innovative CCF technology that has been modified to accommodate the distinct meteorological conditions of Malaysia. The findings suggest that the implementation of advanced glazing technology holds the potential to enhance both operational temperatures and overall occupant comfort within buildings.

Investigation of CCF with TGU as Inner Skin to Reduce Peak Operating Temperature for Thermal Comfort in an Indoor Environment in a Hot, Humid Climate

A closed cavity facade (CCF) is “a sealed, non-ventilated cavity with an automated shading device that, at its simplest, consists of double or triple glazing on the inside and single glazing on the outside”. The dynamic properties of this technology enable the fluid control of solar energy and daylight entering the structure. Several CCF designs were investigated in EnergyPlus and DesignBuilder, and the outcomes were compared to the present state (a single-glazing unit (SGU) with grey coating). The investigation was founded on a case study of a Penang Island, Malaysia, condominium. Comparing CCFs with traditional SGU systems reveals significant thermal performance and occupant comfort enhancements. CCF configurations performed well throughout the year, with maximum operational temperature reductions 40–91% better than traditional SGUs in Malaysia's humid tropical climate. Further investigation revealed that the glass coating and sun shading capabilities substantially contribute to reducing the interior temperature and enhancing the comfort of the building's occupants. The greatest performance was achieved by combining a nanocoating (83/58) and an E-low coating (83/23) (Tvis/Tsol) with a Venetian blind. In light of this, it is essential to carefully consider which coatings to use when installing CCF in such conditions. In all of these regards, the study concentrates on the fact that developing and implementing suitable combinations of a new closed-cavity facade for Malaysia's climate can result in substantial gains. The results demonstrate that building operational temperatures and comfort can be enhanced, highlighting the need for innovative glazing technology.

Sustainable Urban Energy Solutions: Investigating the Solar Potential of Vertical Façades Amidst Adjacent Buildings in Kuala Lumpur, Malaysia

This article explores the impact of adjacent buildings on solar exposure for photovoltaic (PV) applications in high-rise urban areas in Malaysia. The rapid urbanization and population density in Malaysia's high-rise areas have increased energy demand, necessitating the exploration of alternative energy sources. Integrating PV systems into vertical façades offers a promising solution for maximizing energy generation in space-constrained urban environments. However, the efficacy of PV systems is influenced by adjacent buildings, including their arrangement, height, and orientation, which affect solar exposure and energy generation potential. Understanding these effects is crucial for optimizing PV system design and placement. This study aims to investigate the relationship between adjacent buildings and solar exposure for PV panels mounted on high-rise buildings in Malaysia. By examining these effects, the research provides valuable insights for urban planners, architects, and renewable energy practitioners involved in sustainable urban development. The findings will inform decisions regarding the integration of PV systems, promoting renewable energy adoption, and reducing the environmental impact of urban areas. The article also discusses Malaysia's climate, energy consumption, and solar radiation potential, emphasizing the need to harness solar energy in a country blessed with abundant sunlight. The challenges faced by current air conditioning systems and building-integrated photovoltaic (BIPV) applications in Malaysia are outlined, along with efforts to address them through energy-efficient systems and awareness campaigns. The research conducted simulations using a 3D model in Kuala Lumpur, Malaysia, considering different heights and distances of adjacent buildings. The software used for simulations was IES-VE, which offers various modules for energy consumption analysis. The results demonstrate how adjacent buildings affect the annual average energy for different scenarios, highlighting the importance of distance and height. The findings provide insights into the monthly average energy variations and emphasize the relationship between adjacent building height and average energy levels. Overall, this research contributes to the efficient utilization of vertical façades for harnessing solar energy in high-rise urban areas, supporting Malaysia's sustainable energy goals while ensuring urban environment liveability and resilience.

Malaysia's Climate Change Framework and Local Government Response

Climate change is a significant global challenge affecting our planet's ecosystems. Addressing this challenge requires a concerted effort from all stakeholders, including businesses, academic institutions, and government at all levels. This paper examines Malaysia’s national policy on climate change and its legal framework at national and international levels. It also aims to consider the response by local authorities. The discussion adopts the doctrinal legal research analysis. The findings of this paper can provide the policymakers, governments, and local authorities in Malaysia to expedite their climate change mitigation effort.

Tropically Adapted Passive Building: A Descriptive-Analytical Approach Using Multiple Linear Regression and Probability Models to Predict Indoor Temperature

The quest for energy efficiency in buildings has placed a demand for designing and modeling energy-efficient buildings. In this study, the thermal energy performance of a tropically adapted passive building was investigated in the warm tropical climate of Malaysia. Two mock-up buildings were built to represent a “green”, made of clay brick double-glazed passive building and a conventional, made of concrete “red” building. The mean indoor temperature of the passive building was found to be always lower than that of the red building throughout the experiment during different weather constellations. Our research builds upon existing work in the field by combining multiple linear regression models and distribution models to provide a comprehensive analysis of the factors affecting the indoor temperature of a building. The results from the fitted multiple linear regression models indicate that walls and windows are critical components that considerably influence the indoor temperature of both passive buildings and red buildings, with the exception of passive buildings during the hot season, where the roof has a greater influence than the window. Furthermore, the goodness-of-fit test results of the mean indoor temperature revealed that the Fréchet and Logistic probability models fitted the experimental data in both cold and hot seasons. It is intended that the findings of this study would help tropical countries to devise comfortable, cost-effective passive buildings that are green and energy efficient to mitigate global warming.

Survey on solar photovoltaic (PV) technology utilization at residential area at Kampar, Perak

The tropical climate of Malaysia is conducive to the development of solar energy, yet the adoption of solar PV technology in the construction industry is relatively low. Thus, the purpose of this study is to identify the difficulties faced by home users when installing solar PV and to propose recommendations to encourage solar PV. This research was conducted on residential construction sites in Kampar. More than 100 questionnaires were administered physically and online but only 50 responded, which represents a 50% response rate. The respondents were selected purposively mainly among the clients, contractors, developers, and consultants. The data revealed that the major difficulties that the home users encountered in the installation of solar PV include lack of motivation and incentives, huge capital outlay, and inability to secure financial support for the solar PV. To install solar PV, the research found that there is a need to provide attractive loans and incentives, implement policy, educate the households, reduce fossil fuel subsidies, and others. Although this research has been carried out diligently, there are several limitations such as this research only focusing on residential construction projects, having a very small sample size, and this research only using one method for data collection.

Design and evaluation of a modified basin-type stepped solar- still under Malaysia climate conditions

ABSTRACT Distillation represents one of the earliest methods of treating water, and it remains as such in many parts of the world. A basin-type stepped solar-still remains the simplest desalination technology. It is simple, easy to construct, requires minimal maintenance, and is cost-effective. The objectives of this study were to design, fabricate and evaluate the performance of a modified stepped solar-still. The theoretical analysis was conducted to determine the optimum design of the still. The productivity and solar-still efficiency were obtained by solving the energy balance equations for the absorber plate, saline water, and glass cover, the temperature difference between saline water and the glass cover, and evaporation, convective, and radiative heat transfer coefficients under the climate of Malaysia. The experimental setup was constructed, and experiments were conducted at the Universiti Kebangsaan Malaysia (UKM), Selangor (Latitude 2°56‘22“North and Longitude 101°47’16” East). The basin area of the stepped solar-still was 1.m2 (0.5 m × 2.0 m). The basin of the still was constructed from a black-painted galvanized steel sheet to increase the absorptivity. The cover of the still was made up of glass. The absorber plate of the stepped still consisted of 5 steps (0.1 m × 2 m). The stepped solar-still has been modified to include external and internal reflectors, fins, and an external condenser. The performance of the modified stepped solar-still design has been investigated and compared with the unmodified stepped solar-still. The theoretical results show a significant improvement in the performance of the modified stepped solar-still. The productivity was higher than that for stepped solar-still before modification by approximately 29% under the same climate conditions. The experimental results have shown that the maximum temperature of saline water and glass cover were 62.1°C and 56.2°C, respectively. The maximum distillate water in the still was 6.10 kg/m2. The daily efficiency of the modified stepped solar-still was approximately 52.3%. Based on the experimental and theoretical results, the proposed design significantly enhanced the stepped solar-still thermal performance. A statistical t-test was conducted to establish the significance of the difference in the stepped solar-still experimental. It was found that there was a significant improvement in the stepped solar-still performance after modification. The techno-economic analysis showed that the product cost would be around USD0.07 per liter of distillate.

Performance assessment of double pass photovoltaic/thermal solar air collector using bifacial PV with CPC and mirror reflector under Malaysian climate

The performance of photovoltaic thermal (PV/T) type solar collectors can be optimised with the use of bifacial photovoltaic panel since it can utilise the absorbed incident solar irradiance from its front and rear surface. However, its potential is highly determined by the amount of the reflected solar irradiance onto the rear surface of the panel. In this research, we assessed the potential of a novel double pass photovoltaic/thermal (PV/T) solar air collector using semi-transparent bifacial PV panel with compound parabolic concentrator and mirror reflector in Malaysia. The use of CPC and reflector was introduced to increase the amount of reflected light and hence increasing the efficiency of the collector. A mathematical model was developed, and validated o predict the performance of the solar collector. Using the validated mathematical model, the optimum mass flow rate of the bifacial PV/T collector with CPC and mirror reflector was found at 0.0589 kg/s. At this flow rate, when operated under the hot climate of Malaysia, the temperature output of as high as 51 °C is achievable implying its potential as a preheated air to regenerate desiccant materials in solar assisted cooling system and for agriculture drying application. Also, when compared with the bifacial PV/T solar collector without the CPC, the total energy useful was found almost 40% higher.

Comparison of Thermal Comfort Condition of Naturally Ventilated Courtyard, Semi-Outdoor and Indoor Air-Conditioned Spaces in Tropical Climate

Universiti Tun Hussein Onn Malaysia (UTHM) elibrary is in the hot and humid tropical climate of Malaysia and has a distinctive feature of a circular courtyard and semi-outdoor spaces for practical public spaces and energy saving. This study was conducted on the ground level of the library which consists of an open terrace consisting of a cafeteria, a garden in the circular courtyard, and an air-conditioned seminar room. This study aimed to compare the thermal comfort condition of these spaces through physical and subjective measurements. Physical measurement was conducted for air temperature, relative humidity, air velocity and mean radiant temperature at the two selected sampling points on each investigated area positioned at 0.6 meters from the floor. Data were collected for three days in each area during two periods of time; 9 to 11 am and 2 to 4 pm. Subjective measurements were also collected through the distributed questionnaire to 150 respondents to determine the thermal sensation votes (TSV) of each investigated area. Calculations based on physical measurement showed the thermal comfort for both the cafeteria and garden were within 90% thermal comfort acceptability limit. PMV value for the air-conditioned seminar room was -0.45 with a PPD value of 9.03%. Both results complied with the ASHRAE 55 Standards for the acceptable condition for both naturally and air-conditioned spaces. The regression analysis showed that the comfort air temperature range based on the human response method for semi-outdoor spaces and indoor spaces were 24.8 0C to 29.0 0C and 20 0C to 23.5 0C respectively. The PMV regression analysis showed that the comfort air temperature range for indoor space was 22.4 0C to 23.5 0C. Results of the study showed that respondents perceived a higher comfort temperature range in the courtyard and cafeteria compared to indoor air-conditioned spaces, but still within the recommended range of ASHRAE 55 standard. The results of the study concluded that semi-outdoor places can potentially be designed as practical public spaces for comfortable and sustainable spaces.

Evaluation of climate change on the collapse potential of unsaturated cement-treated laterite soil for disaster risk reduction

Extreme weather events and intense rainfall may alter the climate, which would probably affect the geotechnical constructions such as unsaturated embankments. Basically, soil moisture content determines the strength of the unsaturated soil, with wetter soils often being weaker. Although it has been proved that unsaturated condition substantially impacts the shear strength and volumetric behaviour of soil, its implications are rarely investigated or taken into account in the design. As a result, changes in temperature and rainfall loads will have an influence on geotechnical constructions and develop long-term seasonal deformations that might severely jeopardize safety and maintenance. Therefore, it is crucial to assess the effects of the climate on soil behaviour for each location through adequate geotechnical laboratory tests. Johor, Malaysia has a large area and abundant tropical soils. Hence, this study aimed to elucidate the influence of climate change on soil behaviour in the tropical regions of Johor. To impose Malaysia's climate, a series of modified suction-controlled oedometer tests are conducted under different matric suctions. The outcomes revealed that the low and high matric suction has significantly impacted the untreated and cementtreated soil. However, the great reduction of soil settlement is mostly from the coupling effect of saturation and stabiliser.

COMPARISON OF MEASURED SLANT PATH ATTENUATION AT 10.982 GHZ WITH LARGE-SCALE PREDICTION MODELS IN A TROPICAL CLIMATE

Rain-induced attenuation above 10 GHz can be severe at heavy rain rates resulting in deep fading, which can negatively impact the quality of receive signal level at the Earth station receiver. The dearth of direct measurement data in most of the tropical and equatorial climates has motivated the campaign for collection of rain attenuation data on slant paths in these regions. This is mainly due to a huge receiver margin required for such measurement, and which is very difficult to obtain by using a spectrum analyzer. The measurement results of rain rates and rain-induced attenuation in vertically polarized signals propagating at 10.982 GHz in a tropical Malaysian climate are presented in this study. The measured attenuation is compared with large-scale prediction models. As shown in the statistically-tested results, the Bryant model yields the best overall fit, while the Crane model yields the worst overall fit. The results show that the models have relatively good prediction capabilities in the Malaysian tropical climate; however, their prediction errors still need to be minimized. Therefore, in this study, a correction factor is proposed to enhance their predictions.

Analysis of Preferential Flow at the Front Mesh Cartridge of the Gas Mask Filter: Cases in Malaysia Climate Environment

A gas mask respirator is essential for human protection from the hazardous and toxic chemical environment. The gas mask filter should be regularly checked, and the filter must be changed abruptly based on the temporal exposure to the toxic environment. Furthermore, the filter is exposed to a highly humid climate, and the high gas concentration speeds up the expiry cycle of the gas mask filter. Thus, this study aims to investigate the preferential flow absorbed into the gas mask filter and predict the potential area that presents the dead zone. In this study, a three-dimensional model of the commercial gas mask filter was modeled using the computational aided design (CAD) software. Four different humidity ratios of 50%, 60%,70%, and 80% as well as Five different filter concentrations of 20ppm, 100ppm, 200ppm, 300ppm, and 1000 ppm were simulated. The computational fluid dynamic (CFD) method was governed by continuity and Navier-stokes equation to investigate the presence of the dead zone based on several flow parameters. The result showed that the effects of the pressure, velocity, temperature, humidity, and concentration on the gas mask filter were analyzed. The pressure drop is seen in the charcoal filter region which experiences high-velocity circulation. The highest effect on the pressure drop, humidity, and concentration was seen for the case V filter. The high humidity ratio with the pressure drop in the gas mask filter also decreases the efficiency of filter concentration even though the temperature is constant. The high humidity ratio in the mask filter will retain the heat inside the gas mask filter, thus reducing the life cycle of the filter.