Introduction: This study aimed to investigate the concentration of Respirable Crystalline Silica (RCS) and respirable dust, Particulate matters (PM₄ ) concentration in samples measured indoors and outdoors of the nine (9) selected households located proximal to gold mine tailings in Riverlea, Johannesburg.

Materials and methods: Sampling locations were separated according to grids, based on distance from the tailings; A (<500 m from the dump), B (>500m<1 km) and C (1 km-3 km). Three households were selected from each grid zone to measure indoor and outdoor PM4 samples continuously over 24 h using GilAir constant sampling pumps. Samples were collected during dry and wet seasons, and respirable crystalline silica in PM4 samples were analysed by an X-ray diffraction method.

Results: The mean indoor and outdoor PM₄ mass concentrations ranged from 2.02±0.02 µg/m3 to 2.26±0.02 µg/m3 , respectively. The dry season mean for PM4 mass concentrations were higher than the wet season PM4 mass concentrations in all zones. The pairwise comparison of PM4 mass concentration for dry and wet seasons revealed no statistically significant difference (p<0.05). The dry season means the indoor/outdoor ratio was greater than one across all zones, suggesting indoor activities as the primary source of PM. In both seasons, the mean indoor and outdoor RCS ranged from 0.02±0.01% to 0.06±0.03%. The mean indoor and outdoor 24 h RCS concentrations in both seasons were below the California Office of Environmental Health Hazard Assessment (OEHHA) defined 24 h ambient exposure threshold of 3 µg/m³ .

Conclusion: The study found that PM4 concentration was directly proportional to distance from the gold mine tailings. Using RCS as a signature chemical, we found a similar chemical composition in all samples collected in winter and dry season at varied distances. It is concluded that the gold mine tailings are the significant source of PM₄ emissions. Therefore, further dust control measures needs to be implemented at the gold mine tailings

Introduction: Microplastics are a new type of contamination in the environment caused by plastic fragmentation and degradation. The generation of plastic waste increases every year, therefore efforts are made to recycle it into building materials. It is unclear how building use resulting from recycling plastic waste affects the development of microplastics in the atmosphere. The purpose of this study is to determine the airborne concentrations of microplastics in buildings constructed from recycled plastic waste.
Materials and methods: The study measured microplastic levels in the air for 30 days in a miniature building made from plastic waste. Samples taken during the dry season in Indonesia in 2023. Air sampling is carried out by passive method. Visual observation of the shape, and amount of microplastics using a microscope.
Results: Microplastics are found in the air of building spaces made from recycled plastic waste with varying levels every day. The average level of microplasty in the air for 30 days was 30,8 particles/m²/day. Maximum
microplastic rate of 63 particles/m²/day, and minimum rate of 18 particles/m2/day. The average air temperature when sampling is 25,48 ºC, air humidity is68,37 % and ultraviolet intensity is 860 mwatt/cm².
Conclusion: Microplastic levels in the air of building spaces made from recycled plastic waste that can not be identified can be identified whether they are still within safe limits or not. This is because there is no regulation in Indonesia even in the world that regulates the safe limit of microplastic levels in the environment

Introduction: The classroom environment is crucial for fostering effective learning and safeguarding teacher-student health. This study assessed the Indoor Air Quality (IAQ) and noise levels in classrooms across three
institutions: a university, a secondary and higher secondary school (called a school and college), and a primary school.
Materials and methods: Various IAQ parameters such as Particulate Matters (PM_2.5 and PM₁₀), Carbon monoxide (CO), Carbon dioxide (CO₂), Total Volatile Organic Compound (TVOC), and temperature, Relative Humidity (RH), light, and noise levels were measured using calibrated instruments from February to March 2024.
Results: The air pollutants and noise levels varied among the institutions. The mean values of PM_2.5 (76.6 µg/m³) and PM₁₀ (116.7 µg/m3) were highest in the primary school, while CO (0.82 ppm), light (92.9 lux), temperature (27.6 °C), and noise levels (77.6 dB) peaked in the school and college. University classrooms showed the maximum concentrations of CO₂ (804.9 ppm), TVOC (32.9 ppb), and RH (58.6%). In all institutions, PM_2.5, PM₁₀, and noise levels exceeded WHO-recommended limits, whereas CO, CO₂, RH, and temperature remained within their respective standards. Light levels were below Occupational Safety and Health Administration (OSHA) guidelines. Correlation analysis showed significant positive correlations between PM_2.5, PM₁₀, and CO. Hazard Quotient (HQ) values for PM_2.5 and PM₁₀ exceeded 1.0, indicating potential health risks. Variations in pollutants and noise levels among institutions may be due to classroom facilities, student density,
ventilation systems, and student activities.
Conclusion: Long-term exposure to IAQ pollutants and noise levels could impair cognitive function, respiratory health, and overall well-being of the students and educators. Implementing proper ventilation (e.g., HEPA filters) systems, soundproofing acoustic panels, and continuous IAQ monitoring is recommended for a safer classroom environment.

Introduction: Environmental noise, caused by traffic, leads to increased risk of health problems. Nowadays, noise pollution is one of the most important problems in the communities which adversely affects the health. The aim of this study was to assess the noise pollution in Khorramabad city.
Materials and methods: To measure the noise level in the city, 39 stations near to sensitive places such as hospitals, educational centers, and so on were selected. Measurements were performed, for 30 min, in the mornings (7-10 AM) and evenings (5-8 PM) using a standard sound level meter. The measurements were made on working days during the week and assuming the traffic load was the same.
Results: The sound level in all 39 considered stations was higher than the standard of residential-commercial in more than 90% of the stations compared to the environmental standard. The mean of sound measured in the monitored stations was equal to 68.28±2.6 dB. The maximum measured sound level belonged to station S2. In station S2, the maximum measured sound was reported as 81.72±11.3 dB. The findings showed that sound level in the evenings were slightly higher than the mornings. Also, in the evening, the highest and lowest measured sound values belonged to stations S1 and S20. The amount of measured sound level at stations S1 and S20 was equal to 80.9 and 39.7 dB, respectively. Based on findings, the highest and lowest sound recorded belonged to stations S39 and S20 which area type of stations S20 and S39 was commercial and residential, respectively.
Conclusion: This study showed that the average level of sound pressure was higher than the permissible limit, so the necessity of planning is suggested to reduce the level of noise pollution and consequently reduce the anxiety level of citizens and increase health.

Introduction: The present study analyzed the infiltration behavior of sizefractionated particles and the influencing parameters.
Materials and methods: The studies were carried out in two apartments under varying conditions of airtightness, utilizing real-time surveillance of Particulate Matters (PM_0.3, PM_1.0, PM_2.5, PM₁₀), along with air exchange rates and meteorological factors. The seasonal variations of the indoor dissemination of particulate matters have been also discussed.

Results: The analysis of correlations indicated a strong dependency of indoor Particulate Matter (PM) concentrations on outdoor levels. However, the penetration patterns varied across different particle sizes. The highest contribution to outdoor PM₁₀ was observed for PM_2.5-10 while indoors, the predominant particle size was among the finer categories, PM_0.3-1.0. Moreover, window air-tightening appeared to decrease the overall effective leakage area of the building envelope, which in turn slightly lowered the ratio of indoor to outdoor PMs as well as the infiltrability for particles of all sizes. However, this intervention did not alter the distribution of particles within indoor environments. The most penetrated particles were observed in the size range 0.3-1.0 µm and then PM<0.3 µm, and the least in the size range 2.5-10 µm.
Conclusion: Particle dimensions and external sources primarily influenced the degree of particle infiltration, significantly overshading the impact of weather-related factors. The relationship between indoor and outdoor particulate matter was diminished by the airtightness of windows, particularly for larger particles. No notable difference was observed in the infiltrability and indoor distribution of particles of varying sizes between the winter and fall seasons.

Introduction: The use of inefficient and harmful fuels and technology within and outside the home is the primary cause of indoor air pollution. Approximately 2.4 billion people on the planet still cook over open flames and inefficient stoves using solid fuels and kerosene. The availability of cleaner cooking options varies more in rural than in metropolitan settings. Therefore, there is a need to determine the prevalence of indoor air pollution among rural women, its association with respiratory disorders, and the frequency of respiratory illnesses among rural women residing in houses with or without indoor air pollution.
Materials and methods: This analytical cross-sectional study was done for a period of six months from June to November 2020. The study conducted in 210 households living in the rural field practice areas of JSS Medical College, Mysuru. For the selection of villages, a multistage random sampling technique was used. Three villages are selected from the rural setting: Suttur, Hadinaru, and Kadakola. The households were included by probability proportionate to the size sampling technique. Pre-tested, semi-structured, phase and content
validated questionnaires were used to obtain the details on socio-demographic characteristics, meter values of indoor air pollutants like Particulate Matters (PM₁, PM_2.5, PM₁₀) and Volatile Organic Compounds (VOCs), respectively with the factors affecting respiratory illness and the episodes of the illness. Data was entered in Microsoft Excel and analyzed using descriptive and inferential statistics using SPSS V.26.

Results: The prevalence of indoor air pollution in the present study was 13.3%. In the homes of rural women,  here was a statistically significant variation in the concentration of the three particulate matter sources that cause indoor air pollution. Additionally, among the women living in rural families, there was a statistically significant difference in the concentration of PM₁₀ that caused respiratory disease.
Conclusion: The current study demonstrated the higher concentrations of pollutants such as PM₁₀, PM_2.5, and PM_1.0, as well as their significant relation with indoor air pollution in rural families. To prevent indoor air pollution and its health risks, clean energy must be used for household needs.

Introduction: A proper investigation on indoor pollution level in economical apartments is important, where the provision for ventilation is limited. A series of experiments were conducted in the houses within an existing economical apartment in Bhubaneswar, India to evaluate various pollutant levels.
Materials and methods: Temperature, relative humidity, CO, CO₂, Particulate Matter (PM₁₀ and PM_2.5), Formaldehyde and Total volatile organic compounds in the bedrooms and kitchens are measured by pollution meters. The experiments were conducted with doors and windows closed conditions.  The readings were taken on a four consecutive working day in February 2023 at an interval of 3 h (9:00 am to 9:00 pm).
Results: The day wise temperature and humidity variations inside the bedroom and kitchen shows a reverse trend. At the afternoon, the indoor temperature becomes high, while during the night time humidity becomes the highest. The day wise indoor CO₂ and CO variation trend is pretty similar. Both CO₂ and CO concentrations in bedrooms are the highest in the evening. In contrast to that CO₂ and CO concentrations in kitchens becomes maximum during noon time. High particulate matter concentration at outdoor and indoor is observed at the evening time. Higher formaldehyde (HCHO) and Total Volatile Organic Compounds (TVOCs) concentration at the indoor is observed at noon and afternoon time.
Conclusion: The results obtained were compared with the recommended values of World Health Organization (WHO) and National Ambient Air Quality Standards (NAQIS). The results revealed that all measured parameters are at a higher level than the recommended values except the indoor CO₂ concentrations.

BTEX is a group of hazardous chemical compounds that include benzene, toluene, ethylbenzene, and xylene. The indoor concentration of BTEX is mostly influenced by tobacco smoking, the region within the house, and seasonal variations. This study included three databases: "Google Scholar", "Science Direct", and "Springer". Out of the 1351 articles obtained from the keyword search, only 13 were eventually selected for this study. The most abundant compound found in houses among BTEX was toluene, with a concentration of 13.80±16.50 µg/m³. The results indicated that the concentration of benzene in houses where smoking occurred was greater than in houses where no smoking occurred (7.17±9.42 vs. 2.65±3.77 µg/m³, unpaired Wilcoxon test: p>0.05). The concentration of BTEX in houses was substantially lower than that in cafes (21.10±31.10 vs. 15,100±9740 µg/m³, unpaired Wilcoxon test: p<0.05). The urban region had the most significant accumulation of all BTEX chemicals, with the industrial and rural sectors following suit. The findings indicated that the average levels of BTEX in warm months (such as spring and summer) were higher than in cold months (such as fall and winter) within houses (28.50±44.30 vs. 8.60±7.77 µg/m³, unpaired Wilcoxon test: p > 0.05). The findings indicated that the cancer risk (CR) associated with houses (3.11×10^-6) and cafes (3.54×10-3) exceeded the permissible threshold. Moreover, the waterpipe cafes that utilized fruit-flavored tobacco had the greatest CR (4.98×10^-3). Furthermore, the presence of smoking, regional factors, and seasonal variations did not result in an increase in the hazard quotient (HQ) in houses beyond the acceptable thresholds.