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.
Haseeb Tufail Moryani, Shuming Zhu, Li-Ping Wang et al.· Toxics· 0 citations
China has invested heavily in air pollution control in recent years, yet comprehensive assessments of the associated health economic benefits remain limited. Prior research on the health economic benefits of air pollution control has mainly focused on mortality outcomes and PM2.5, which may substantially underestimates the true benefits of clean air policies. This study aims to evaluate the health economic benefits and losses associated with air pollution control by incorporating multiple health outcomes, population groups and air pollutants. We integrate daily mortality, hospital admission and outpatient visits and air pollutant (nitrogen dioxide, ozone [O3] and fine particulate matter) data from 18 cities from 2015 to 2022 to assess the health economic benefits. A generalized additive model was used to estimate concentration-response relationships. Health economic benefits were calculated based on the value of statistical life (VSL) and direct medical costs. Between 2015 and 2022, controlling PM2.5 and NO2 yielded significant health economic benefits across all health outcomes. Air pollution control generated significant health economic benefits across multiple outcomes in Guangdong Province. The total health economic benefits associated with PM2.5 and NO2 were 10,305.35 and 1017.00 million CNY, respectively. In contrast, O3 control yielded negative net benefits across all outcomes. Between 2015 and 2022, the multi-outcome health benefits of controlling PM2.5 exceeded mortality-only estimates by 31.79%, respectively For PM2.5 control, the elderly accounted for over 85% of the mortality-related benefits. These findings highlight the need for coordinated PM2.5-O3 control, the integration of multi-outcome evaluations into policy design, and targeted protection for vulnerable populations particularly the elderly.