An exploration task can be performed by a team of mobile robots more efficiently than human counterparts. They can access and give live updates for hard-to-reach areas such as a disaster site or a sewer. However, they face some issues hindering them from optimal path planning due to the symmetrical shape of the environments. Multiple robots are expected to explore more areas in less time while solving robot localization and collision-avoidance issues. When deploying a multi-robot system, it is ensured that the hardware parts do not collide with each other or the surroundings, especially in symmetric environments. Two types of methods are used for collision avoidance: centralized and decentralized. The decentralized approach has mainly been used in recent times, as it is computationally less expensive. This article aims to conduct a systematic literature review of different collision-avoidance strategies and analyze the performance of innovative collision-avoidance techniques. Different methods such as Reinforcement Learning (RL), Model Predictive Control (MPC), Altruistic Coordination, and other approaches followed by selected studies are also discussed. A total of 17 studies are included in this review, extracted from seven databases. Two experimental designs are studied: empty/open space and confined indoor space. Our analysis observed that most of the studies focused on empty/open space scenarios and verified the proposed model only through simulation. ORCA is the primary method, against which all the state-of-the-art techniques are evaluated. This article provides a comparison between different methods used for multi-robot collision avoidance. It discusses if the methods used are focused on safety or path planning. It also sheds light on the limitations of the studies included and possible future directions.

This study assesses Sick Building Syndrome (SBS) symptoms and Indoor Air Quality (IAQ) parameters among hospital ward staff. Utilizing a thorough methodology, a questionnaire survey and IAQ monitoring were conducted, aligning with Department of Occupational Safety and Health (DOSH) guidelines. IAQ parameters are generally within limits, except for relative humidity which recorded values of 73.09-75.23% for Ward 16 and 62.33-71.13% for Ward 18. Respondents expressed concerns about room conditions, including temperature variations, unpleasant odours, and noise. Fatigue, difficulties concentrating, and various respiratory symptoms were prevalent, suggesting potential health issues linked to indoor pollutants. The findings underscore the urgency of addressing IAQ concerns to improve the well-being of patients and healthcare workers.

Exposure to types of asbestos such as chrysotile and crocidolite increases respiratory disease risks such as lung cancer, mesothelioma, and asbestosis. Nevertheless, asbestos products banning in Malaysia is only limited to crocidolite as per stated in OSHA (Prohibition of Use of Substance) Order 1999, though other types are highly suspected to be found in asbestos-containing materials (ACM) like brake pads and linings. This study ascertains the presence of asbestos fibres, particularly chrysotile, in brake pads and linings used in Malaysia's vehicle and heavy vehicle sector. Seven different brake pads; three from vehicle brands, and four from heavy vehicle brands were collected by bulk sampling approaches from the market and field. Dust fibres were extracted using slow grinding method and analysed under Polarized Light Microscope (PLM). The fibre characteristics such as colour, morphology, pleochroism, extinction, and dispersion staining technique were examined, referring the National Institute for Occupational Safety and Health (NIOSH) Manual of Analytical Methods (NMAM) 9002. Additionally, the observed samples also were verified by an accredited lab to support the authenticity of the outcome. From the analysis and lab results, chrysotile fibres were consistently detected in all brake pad samples, fulfilling the fibre characteristics and positive elongation signs.

This study investigates the relationship between Indoor Air Quality (IAQ) and air duct cleanliness, addressing the rising concern for human well-being. Airborne contaminants like dust, mold, and bacteria are identified as significant threats to IAQ, with potential health consequences. The study will also explore the several established safety and health guidelines and duct characteristics that influenced IAQ. Consequently, the primary research goal is to examine the relationship between duct cleanliness and airborne contaminants in the building environment and determine whether air duct cleaning effectively reduces these contaminants. By thoroughly reviewing studies and established standards, we examine IAQ contaminants and explore the effects of duct cleaning, along with its potential health advantages. Findings emphasize duct cleaning's potential to enhance IAQ, reduce exposure to pollutants, and its importance for building owners, facility managers, and stakeholders in safeguarding occupants' health and comfort.

Heating ventilation and air conditioning system (HVAC) is very important for offices building and human health. The combining filter method was used to reduce the air pollution indoor such as that particulate matter and gases pollution that affected in health and productivity. Using particle filters in industrial HVAC systems (factories and manufacturing process) does not enough to remove all the indoor pollution. The main objective of this study is to investigate the impact of combination filters for particle and gases removal efficiency. The combining method is by using two filters (particulate filter pre-filter and carbon filter) to reduce particle matter and gases respectively. The purpose of this study is to use minimum efficiency reporting value (MERV filter) rating 13 and activated carbon filter (ACF) to remove indoor air pollution and controlling the air change rate to enhance the air quality and energy saving. It was concluded that the combination filter showed good removal efficiency of particle up to 90.76% and 89.25% for PM₁₀ and PM_2.5 respectively. The pressure drop across the filters was small compared with the high-efficiency filters. The filtration efficiency of combination filters after three months' was better than efficiency by the new MERV filter alone.