Characteristics, Sources, and Health Risks of PM2.5-Bound Heavy Metals in School Environments: A Comparative Study of Two Cities in South China.

Human health risk assessment of PM2.5-bound heavy metals during a haze season in a semi‑urban agricultural area of Northern Thailand.

Findings identify Cr containing PM2.5 inhalation during haze episodes as a priority health concern, particularly for children, underscoring the need for targeted emission controls in semi-urban-agricultural areas.

Inhalation Bioaccessibility, Pollution Assessment, and Speciation of Heavy Metals in PM2.5RD Road Dust from Urban and Semi-Urban Areas of Pakistan

Ambient exposure to fine particulate matter (PM2.5) remains a critical global public health concern; however, the speciation and bioaccessibility mechanisms of particle-bound heavy metals within the lung environment are still insufficiently understood. In particular, the role of soluble and insoluble metal species in simulated lung fluids requires further clarification. Road dust, a major contributor to PM2.5, contains heavy metals that pose significant inhalation risks, leading to oxidative stress, DNA damage, and systemic toxicity. This study investigated the contamination characteristics, bioaccessibility, pollution level, and speciation of heavy metals in PM2.5-fractionated road dust (PM2.5RD) collected from Karachi (a megacity with >27 million inhabitants) and Shikarpur (a medium-sized city of ~0.3 million) in Pakistan. A grid-based sampling approach was applied across four functional zones (residential, school, hospital, and office), yielding 48 samples. Inhalation bioaccessibility was evaluated using artificial lysosomal fluid (ALF; pH 4.5, 37 °C, 24 h), revealing moderate bioaccessibility of Cr, As, and Pb. Pollution status was assessed using contamination factor (CF), integrated pollution index (IPI), pollution load index (PLI), and potential ecological risk index. Geochemical modeling with PHREEQC 3.0 and Visual MINTEQ 3.1 was employed to simulate metal speciation, release behavior, and mineral saturation states. Overall, this study provides mechanistic insights into speciation-driven toxicity of As, Pb, and Cr in simulated lung environments, offering a scientific basis for improved risk assessment and regulatory strategies for PM2.5-associated metal exposure.

Size-fractionated PM-bound metals and associated health risks in the densely populated megacity of Southern Vietnam: a preliminary investigation

Size-fractionated particulate matter analysis is key to understanding how particle size influences health risks. However, data on metals distribution and respiratory deposition across PM sizes in Southeast Asia is still scarce. In this study, we evaluated the levels, size distribution, and health-related impacts of metals in particulate matter (PM) from Ho Chi Minh City (HCMC), the most densely populated urban in Southern Vietnam. Sampling was performed monthly with a five-stage nano-sampler (PM< 0.5, PM0.5−1, PM1−2.5, PM2.5−10, and PM> 10). Concentrations of 8 metals were analyzed by ICP-MS, and the levels were observed in the following order: Al (1741 ng m− 3) > Fe (958 ng m− 3) > Zn (731 ng m− 3) > Pb ( 22.6 ng m− 3) > Mn (21.3 ng m− 3) > Cu (19.4 ng m− 3) > Ni ( 4.86 ng m− 3) > Cd (0.52 ng m− 3). Crustal metals (Al and Fe) predominantly resided in the coarse particulate fraction, whereas anthropogenic metals (e.g. Pb, Zn, and Cd) were enriched in fine particles. Deposition modeling indicated that crustal metals were mostly retained in the head region (62–72%), while anthropogenic metals were deposited more in deeper lung regions (7–12%). The health risk assessment showed that the Hazard Index (HI) was markedly higher in children than in adults for both PM2.5 and PM10. Specifically, the HI for children was 1.95 for PM2.5 and 3.54 for PM10, whereas for adults, these values were 0.49 and 0.88, respectively. Regarding cancer risk, Total Cancer Risk (TCR) for children reached 1.31 × 10− 5 for PM2.5 and 1.75 × 10− 5 for PM10, exceeding the low-risk threshold. In contrast, the TCR for adults was considerably lower at 3.26 × 10− 6 and 3.0 × 10− 6. These findings indicated the importance of size-resolved PM studies to better understand exposure characteristics and potential health risks posed by toxic elemental contaminants.

Pollution characteristics and health risks of PAHs and OPAHs in PM2.5 of an inland basin city in China under the influence of the clean air action plan

Characteristics, Sources, and Health Risk Assessment of Potentially Toxic Elements in Road Dust PM2.5 in Northwest China

Concentrations and Health Implications of PM2.5, PM10, and Gaseous Pollutants in Communities near Ibom Power Company, Ikot Abasi, Nigeria

Particulate Matter (PM) exposure from ambient air has been linked to a number of ailments, and monitoring is necessary in every industrial areas or centers to identify overexposure early. This study's assessed the concentrations of PM2.5, PM10, and related gaseous pollutants in Ibom Power Company, Ikot Abasi, Nigeria, including carbon monoxide (CO), ozone (O3), and nitrogen dioxide (NO2). The concentrations of PM2.5, PM10, NO2, CO, and O3 at three chosen towns surrounding Ibom Power Company were measured using an aerosol mass monitor. The hazard quotient (HQ) of the average hourly dose (AHD) and average daily dose (ADD) exposures to the particles was calculated using the obtained values. The findings showed that, with the exception of Ikpetim, where the values (5.26±0.21 and 5.16±0.20 μg/m3) were below the permitted limits, all of the villages had PM 2.5 and PM 10 levels over the 15μg/m3 permissible range advised by the WHO. With the exception of Ikpetim, where the NO2 value was within the limit, all settlements had CO and NO2 values over the 25μg/m3 and 7μg/m3 acceptable levels, respectively. In the meantime, O3 levels were within allowable bounds (<100μg/m3) in every community. In several places, the HQ of the ADD was higher than 1, yet the HQ of the AHD of the pollutants was below the threshold of 1. The findings suggest that daily exposure to PM2.5, PM10, NO2, and CO in certain areas can have detrimental effects on residents' health. It is recommended that government agencies responsible for health and the environment develop policies aimed at reducing pollution, and power plants should not be located near residential areas, but specific areas should be designated for power plant siting.