Air pollution has emerged as a major global public health concern, with particulate matter pollution (PMP) having particularly significant impacts on human health (1). Particulate matter pollution (PMP) can be broadly categorized into outdoor (ambient) and indoor pollution. Ambient particulate matter pollution (APMP) primarily originates from outdoor sources such as vehicle emissions and industrial activities. Indoor PMP includes various sources within enclosed spaces, with household air pollution from solid fuels (HAP-SF) being a significant component, especially in developing countries (2, 3). While recent acceleration in globalization and industrialization has exacerbated APMP issues globally, HAP-SF continues to pose a serious health threat, especially in developing countries (4). These two forms of pollution present distinct challenges across different regions and socioeconomic contexts, necessitating targeted approaches in addressing their health impacts.

The older adult, being a vulnerable population, are highly susceptible to air pollution (5). Studies indicate that long-term exposure to particulate matter may accelerate lung function decline in older adults and increase morbidity and mortality rates for cardiovascular and respiratory diseases (6).

Research by Cohen et al. revealed that in 2015, approximately 4.2 million premature deaths globally were attributable to PM2.5 exposure, with a significant proportion among the older adult (7). As global population aging intensifies, the impact of particulate matter pollution on older adult health has garnered increasing attention (8). The World Health Organization (WHO) reflected the urgent need for air quality improvement in its 2021 updated guidelines, lowering the annual PM2.5 concentration limit from 10 μg/m³ to 5 μg/m³.

However, long-term trend studies on the health effects of particulate matter pollution on the older adult remain insufficient. Stanaway et al. analyzed changes in deaths and disease burden caused by air pollution from 1990 to 2017 using Global Burden of Disease Study (GBD) data, but did not specifically focus on the older adult population (9). Li et al.’s research, centered on older adult Chinese, found a significant positive correlation between PM2.5 concentration and older adult mortality rates from 2013 to 2017, but lacked a global perspective (10).

Given this context, our study aims to comprehensively analyze global trends in older adult deaths and disability-adjusted life years (DALYs) caused by particulate matter pollution (including APMP and HAP-SF) from 1991 to 2021. Utilizing the latest GBD 2021 research data, we will explore differences between regions, countries with varying levels of socioeconomic development, and the influence of age and gender factors.

The significance of this study is threefold: (1) It evaluates the effectiveness of global particulate matter pollution mitigation efforts over the past three decades through long-term trend analysis; (2) It provides a basis for formulating targeted air quality improvement strategies by comparing changes in APMP and HAP-SF impacts; and (3) By focusing on the older adult population, it offers important references for addressing environmental health challenges in the context of population aging. The results will aid policymakers, public health experts, and environmental scientists in better understanding and addressing the impact of particulate matter pollution on older adult health.

This study provides a comprehensive analysis of global trends in the health impacts of PMP on the older adult from 1991 to 2021. Our findings both support and extend previous research on the impacts of PMP on older adult health. The increasing absolute numbers of PMP-related deaths and DALYs among the older adult from 1990 to 2021, despite decreasing age-standardized rates, aligns with global trends reported by Cohen et al. (7). However, our results show a more pronounced increase in APMP-related burden among the older adult compared to general population trends reported by Burnett et al. (2), likely reflecting the increased vulnerability of the older adult to air pollution.

Our analysis revealed a complex interplay between demographic shifts and air quality trends. We observed a significant increase in absolute numbers of APMP-related older adult deaths and DALYs, which aligns closely with global population aging trends (11). This increase in absolute burden underscores the growing public health challenge posed by APMP in an aging world. However, we also noted a slight decrease in age-standardized rates, suggesting a reduction in overall risk. This paradoxical finding likely reflects the positive outcomes of global air quality improvement measures, which have partially mitigated the increased vulnerability of a growing older adult population (12). Despite these improvements, it’s crucial to recognize that APMP remains a serious public health issue, particularly in rapidly urbanizing and industrializing regions (13). The persistent high burden in these areas highlights the need for targeted interventions that consider both demographic changes and economic development patterns. As urbanization continues globally, addressing APMP will require innovative strategies that balance economic growth with stringent air quality controls, especially in regions experiencing rapid industrial expansion.

The health burden attributed to HAP-SF showed a marked decreasing trend, likely due to the promotion of clean energy and improvements in indoor environments (14–16). However, HAP-SF continues to pose significant health threats in some low-and middle-income countries, especially in sub-Saharan Africa (17). Notably, indoor emissions escaping outdoors have become a major source of ambient fine particulate matter pollution in these regions (18). This phenomenon underscores the urgency of promoting clean energy use globally and highlights the close connection between indoor and outdoor air pollution. Addressing HAP-SF can thus improve indoor environments and significantly reduce outdoor air pollution, particularly in resource-limited areas.

Our study revealed significant age and gender disparities in the health impacts of APMP and HAP-SF. PMP-related mortality and DALYs rates increased with age, consistent with the heightened vulnerability of the older adult due to physiological decline and weakened immunity (6). Gender disparities, with females generally experiencing higher health burdens, stem from multiple factors. First, cultural practices and gender roles in many societies often result in women spending more time indoors, particularly in low-and middle-income countries. This increased exposure to household air pollution, especially from solid fuel use (HAP-SF), may partially explain the higher burden among women (19). For instance, in rural areas of South Asia and sub-Saharan Africa, women are typically responsible for cooking and household chores, leading to prolonged exposure to indoor air pollutants (20). Biological differences may also play a role. Some studies suggest that women might be more susceptible to the adverse effects of air pollution due to differences in lung anatomy and physiology, hormonal factors, and differential deposition of particulate matter in the lungs (21). For example, women tend to have smaller airways relative to lung size compared to men, which may increase their vulnerability to respiratory pollutants (22). These findings emphasize the need for gender-specific considerations in air pollution control strategies, such as targeted education programs for women, improved indoor cooking facilities, and stricter workplace air quality standards.

Our study revealed significant regional disparities in PMP-related health burdens among the older adult, with Asia and Africa bearing disproportionately high burdens compared to other regions. These disparities likely stem from a complex interplay of socioeconomic and environmental factors. In the case of APMP, the high burden observed in East Asia, South Asia, and parts of Africa can be attributed to rapid industrialization and urbanization, often occurring without adequate environmental regulations or enforcement (23). Many cities in these regions face severe air pollution due to industrial emissions, vehicular exhaust, and construction activities. Additionally, geographical and meteorological factors, such as dust storms in North Africa and Eastern Asia, exacerbate the problem in certain areas (24).

The high HAP-SF burden in Central and Eastern Africa, parts of South Asia, and some Southeast Asian countries is closely linked to poverty and lack of access to clean cooking fuels and technologies (25, 26). In contrast, Western Europe, high-income Asia-Pacific countries, and North America have significantly lower burdens of both APMP and HAP-SF, benefiting from decades of stringent air quality regulations, advanced pollution control technologies, and widespread access to clean cooking fuels (27). These regional disparities underscore the need for targeted policy interventions, including stricter emission standards and promotion of cleaner technologies for APMP, and expanded access to clean cooking fuels for HAP-SF. Notably, the lack of correlation between APMP-related health burden and SDI indicates that APMP is a global issue requiring concerted efforts from all countries. In contrast, the strong negative correlation between HAP-SF and SDI underscores the importance of promoting socioeconomic development to improve indoor air quality (28).

Our findings provide crucial evidence for developing targeted air quality improvement strategies, highlighting the need for differentiated approaches to address APMP and HAP-SF. For APMP, which shows no significant correlation with socioeconomic development, there is a need to strengthen regional cooperation to address transboundary pollution issues. This approach should be coupled with enhanced environmental regulation and clean technology application in rapidly urbanizing areas, regardless of their development status (29). In contrast, HAP-SF, which demonstrates a strong negative correlation with socioeconomic development, requires continued promotion of clean energy use, particularly in low-and middle-income countries (30). This stark difference in the relationship between these two types of pollution and socioeconomic development underscores the complexity of addressing PMP globally and the need for context-specific interventions.

This study has several limitations. First, due to data availability constraints, we were unable to analyze changes at finer geographical scales or shorter time intervals. Second, our focus on mortality and DALY indicators may not fully capture the comprehensive impact of particulate matter pollution on older adult quality of life. Future research should consider incorporating additional health indicators, such as hospitalization rates and chronic disease incidence, to provide a more comprehensive assessment. Furthermore, this study did not explore in depth the interactive effects of particulate matter pollution and other environmental factors (e.g., temperature, humidity) on older adult health, which represents an important direction for future research (31).

Our study provides valuable insights into long-term trends of particulate matter pollution’s impact on global older adult health. Our results emphasize the importance of continued air quality improvement, especially in the context of population aging challenges. Moving forward, increased interdisciplinary and intersectoral collaboration is necessary to develop more effective policies and interventions to protect older adult health and achieve sustainable development goals. These efforts should include targeted clean cooking initiatives to reduce HAP-SF exposure, particularly in areas where women are primarily responsible for cooking. Simultaneously, health education for the older adult should be strengthened to enhance their awareness of air pollution risks and self-protection capabilities, with a focus on gender-specific programs that address women’s higher vulnerability to air pollution. Additionally, urban planning and public health policy formulation should specifically consider the needs of the older adult, such as increasing green space and optimizing public transportation systems, to reduce their exposure to particulate matter pollution. This gender-responsive urban planning approach should ensure that public spaces frequented by older adult women have adequate air pollution mitigation measures. Furthermore, we recommend integrating gender considerations into national and local air quality policies to address the specific needs and vulnerabilities of older adult women. Finally, encouraging more research on the biological mechanisms underlying gender differences in air pollution susceptibility could inform more targeted medical interventions and prevention strategies, ultimately leading to more equitable and effective approaches to reduce PMP-related health burdens among the older adult population.

In conclusion, addressing particulate matter pollution is not just an environmental issue, but a matter of intergenerational justice and sustainable development. As we face an increasingly aged global population, the choices we make today will determine the health and well-being of generations to come. This study serves as a call to action for more research, stronger policies, and a collective commitment to ensuring clean air and healthy aging for all.