Indoor Air Quality and Associated Public Health Impact in AC and Non‐AC Environments: A Case Study on Mymensingh, Bangladesh

Environmental Impact Assessment of Indoor Air Quality in Selected Residential Areas in Port Harcourt Metropolis

Indoor air pollution is an emerging environmental and public health challenge, particularly in rapidly urbanizing cities where household activities, energy use, and poor ventilation contribute to deteriorating air quality. This study assessed the environmental impact of indoor air quality in selected residential areas of Port Harcourt Metropolis, Nigeria. A cross-sectional design was adopted, involving instrumental measurements of particulate matter (PM₂.₅ and PM₁₀) and meteorological parameters using a BOSEAN gas meter and EGVOC air quality meter, alongside a structured questionnaire administered to 249 respondents. Measurements were taken at breathing zone height (1.1 m) across ten residential locations over a one-week period, and data were analyzed using descriptive statistics and compared with relevant standards. Results showed that PM₂.₅ concentrations ranged from 47.90 to 59.60 µg/m³, while PM₁₀ ranged from 54.80 to 68.40 µg/m³, with higher values recorded in densely populated and high-traffic areas such as Mile Three and Aggrey Road. Temperature ranged from 26.4°C to 28.4°C and relative humidity from 55.9% to 66.1%. Household data indicated widespread use of gas (40.2%) and kerosene (34.5%) for cooking, frequent generator use, and regular use of chemical-based household products, all contributing to indoor pollution exposure. Reported symptoms included dry throat (25.7%), headache (20.1%), and cough (12.4%). The study concludes that indoor air quality in the study area is moderately polluted and influenced by household practices and urban activities, posing potential health risks. It recommends the adoption of cleaner energy sources, improved ventilation, regulation of generator emissions, and increased public awareness to reduce exposure and improve indoor environmental quality.

Assessment of PM2.5 exposure and respiratory health risks for vulnerable populations in urban underpass: a predictive MLR approach in Chiang Mai, Thailand

Short-term Monitoring of Indoor Particulate Matter (PM) Using Low-cost Sensors in a Residential Environment in Bengaluru, India

Indoor air quality is an important factor in maintaining a healthy living environment. In this study, indoor particulate matter concentrations (PM₁, PM₂.₅ and PM₁₀) were monitored in a residential living room in Bengaluru, India which is naturally ventilated, using a low-cost SmileDrive air quality sensor. Measurements were taken at hourly intervals over three consecutive days from 18 to 20 March 2025, along with temperature and relative humidity. The results showed that particulate matter concentrations varied throughout the day, with PM₁₀ recording higher values than PM₂.₅ and PM₁. The daily mean concentrations ranged from 10.47–12.24 µg m⁻³ for PM₁, 14.26–16.76 µg m⁻³ for PM₂.₅, and 16.21–19.24 µg m⁻³ for PM₁₀. Overall, the measured concentrations indicated relatively good indoor air quality during the monitoring period. Temperature and relative humidity also showed normal daily fluctuations. An analysis of the relationship between relative humidity and particulate matter concentrations revealed that the strength of the correlation varied across the three days, with stronger associations observed on 19 and 20 March 2025. The study demonstrates that low-cost sensors can be effectively used for short-term indoor air quality monitoring and can give useful information on the behaviour of particulate matter in residential environments.

Linking ambient air pollution to health risk burden: A comparative study across urban and semi-urban regions of Karnataka, India

Introduction: Ambient air pollution poses significant public health challenges across urban and semi-urban India. Karnataka, encompassing coastal, plateau, highland, and semi-arid environments, provides an ideal setting for evaluating regional air quality variability and associated health risks. This study assessed the spatio-temporal characteristics of ten criteria and hazardous air pollutants measured at five Central Pollution Control Board (CPCB) Continuous Ambient Air Quality Monitoring Stations (CAAQMS) across Karnataka during 2024. Materials and methods: Monthly mean concentrations of Particulate Matters (PM₂.₅, PM₁₀), Nitrogen dioxide (NO₂), Sulfur dioxide (SO₂), Carbon monoxide (CO), Ozone (O₃), Ammonia (NH3), and benzene were analysed across four India Meteorological Department (IMD) seasons. Serial autocorrelation was assessed using the lag-1 Kendall statistic prior to applying the Mann–Kendall test and Sen's slope estimator as an exploratory assessment of intra-annual monotonic tendencies. Spatial variability was evaluated using one-way ANOVA with Tukey's HSD post-hoc test and validated using the Kruskal–Wallis test. Inhalation health risks were assessed using the USEPA Risk Assessment Guidance for Superfund (RAGS) methodology by estimating Hazard Quotient (HQ), Hazard Index (HI), and Lifetime Cancer Risk (LCR). Results: Bengaluru recorded the highest annual mean PM₂.₅ (40.2 μg/ m³) and PM₁₀ (80.4 μg/m³) concentrations, with PM₂.₅ equal to the CPCB National Ambient Air Quality Standard (NAAQS) and PM₁₀ exceeding it by approximately 34%. Annual mean PM₂.₅ concentrations at all stations exceeded the WHO 2021 Air Quality Guideline (15 μg/m³). The southwest monsoon produced the greatest reduction in particulate concentrations. Exploratory Mann–Kendall analysis yielded negative Sen's slopes for PM₂.₅ at all stations, although none were statistically significant (p>0.05). One-way ANOVA confirmed significant spatial heterogeneity among monitoring stations (p < 0.001). Screening-level health risk assessment indicated HI values >1.0 at all stations (1.756–3.290). Estimated PM₂.₅ LCR ranged from 1.76 × 10⁻³ to 3.34 × 10⁻³ and represents hypothetical upper-bound screening estimates rather than regulatory cancer risk values. Conclusion: Particulate matter remains the dominant air quality concern across Karnataka, particularly in Bengaluru. Strengthened emission control measures, continued multi-year monitoring, and agricultural ammonia management are recommended to support long-term improvements in air quality and public health.

EXPERIMENTAL INVESTIGATION OF OUTDOOR AIR QUALITY AT A TERTIARY INSTITUTION GATE

Air pollution is the reduction in the outdoor or indoor environment quality by any physical, biological or chemical agents above the ambient level that can modify the natural characteristics of the atmosphere. Air pollution can cause long-term and short-term health effects. In this paper air quality of an institutional environment was evaluated and presented based on selected air pollutants, air quality indices (AQI), hazard ratio and lifetime cancer risk. Air quality measurements were conducted at Obafemi Awolowo University Road 1gate for three months. The Air quality indices were computed using standard methods and procedures. The study revealed that mean, skewness and kurtosis of temperature, relative humidity, total organic compounds (TVOC), Carbon dioxide (CO ) and HCHO were temperature (34.2, 34.3oC; 0.6 and 0.6; -0.4 and -0.4); relative humidity (35.46 and 39.23 %; 1.52 and 1.54; and 1.67 and 1.73),TVOC (0.753 ppm and 0.660 ppm; 1.501 and 1.541; and 1.331 and 1.116), CO2 (926.77ppm and 803.77 ppm; -0.70 and -0.63; -1.27, and -1.22) and HCHO (0.051 ppm and 0.048 ppm; 1.123 and 1.51; and 0.504 and 1.69), respectively. AQI for CO2, TVOC and HCHO were between 135 and 336, 16.72 and 173.02, 12.37, and 2191.42, respectively. Life cancer risk for CO , TVOC and HCHO were between 2.42 x 10-3 and -3                                 -6                                            -5                                 -8                                             -6              2 6.02 x 10 , 2.36 x 10 and 9.06 x 10 , 2.63 x 10 and 2.36 x 10 respectively. It was concluded that AQI in-term of CO2 was high (poor and polluted) but fair for TVOC and HCHO. There is a need to reduce CO2 concentration as an increase in CO concentration has been associated with cardiovascular diseases, high blood pressure and chronic kidney disease.      

Long-Term Assessment of Ambient Air Quality, Meteorological Influence, and Transboundary Transport in a Tier-II Indian City