Particulate Matter–Induced Health Effects: Who Is Susceptible?

Abstract

BackgroundEpidemiological, controlled human exposure, and toxicological studies have demonstrated a variety of health effects in response to particulate matter (PM) exposure with some of these studies indicating that populations with certain characteristics may be disproportionately affected.ObjectiveTo identify populations potentially at greatest risk for PM-related health effects, we evaluated epidemiological studies that examined various characteristics that may influence susceptibility, while using results from controlled human exposure and toxicological studies as supporting evidence. Additionally, we formulated a definition of susceptibility, building from the varied and inconsistent definitions of susceptibility and vulnerability used throughout the literature.Data synthesisWe evaluated recent epidemiological studies to identify characteristics of populations potentially susceptible to PM-related health effects. Additionally, we evaluated controlled human exposure and toxicological studies to provide supporting evidence. We conducted a comprehensive review of epidemiological studies that presented stratified results (e.g., < 65 vs. ≥ 65 years of age), controlled human exposure studies that examined individuals with underlying disease, and toxicological studies that used animal models of disease. We evaluated results for consistency across studies, coherence across disciplines, and biological plausibility to assess the potential for increased susceptibility to PM-related health effects in a specific population or life stage.ConclusionsWe identified a diverse group of characteristics that can lead to increased risk of PM-related health effects, including life stage (i.e., children and older adults), preexisting cardiovascular or respiratory diseases, genetic polymorphisms, and low-socioeconomic status. In addition, we crafted a comprehensive definition of susceptibility that can be used to encompass all populations potentially at increased risk of adverse health effects as a consequence of exposure to an air pollutant.

Variability in the fraction of ambient fine particulate matter found indoors and observed heterogeneity in health effect estimates

“…Although PM 2.5 components associated with primary combustion sources might be more toxic than others, our results suggest that fresh combustion particles also penetrate and persist indoors with a higher efficiency than secondary sulfate because of their smaller depositional losses. Low socioeconomic status, a predictor of susceptibility to PM-related health effects, 12 affects F because lowincome residences tend to have higher AER values and are more likely to live in close proximity to busy roadways. Our results suggest that both factors enhance exposure to ambient PM 2.5 .…”

“…Low socioeconomic status has also been identified as a predictor of susceptibility to PMrelated health effects. 12 Various factors have been explored to explain this variability. Bell et al 5 concluded that as much as 37% of spatial and seasonal heterogeneity in relative risk of cardiovascular hospital admissions could be explained by variability in exposure to specific PM 2.5 species.…”

“…Bell et al 5 concluded that as much as 37% of spatial and seasonal heterogeneity in relative risk of cardiovascular hospital admissions could be explained by variability in exposure to specific PM 2.5 species. Sacks et al 12 identified disparities in access to health care as one possible contributor to variability in effect estimates by socioeconomic status. Here, we explore whether variability in the fraction of ambient PM 2.5 that penetrates into and persists in the home is also a possible contributor to observed heterogeneity in fine-PM-mediated health effect estimates.…”

Cardiovascular and Cerebrovascular Emergency Department Visits Associated With Wildfire Smoke Exposure in California in 2015

“…PM 2.5 passes deep into the lung and has been shown to increase systemic inflammation, oxidative stress, and coagulation through PM 2.5 ‐mediated changes in the autonomic nervous system 11, 14. This has been linked to cardiovascular health impacts such as ischemic heart disease and cerebrovascular events such as ischemic stroke in the ambient air pollutant PM 2.5 literature 11, 15, 16, 17, 18. Other air pollutants in wildfire smoke have also been linked to cardiovascular and respiratory outcomes in urban and ambient air pollution studies, including nitrogen oxides, carbon monoxide, and ozone 7, 8, 9, 10…”

The effects of air pollution on respiratory health in susceptible populations: a multilevel study in Bucaramanga, Colombia

“…Children and older or chronically sick individuals are most susceptible to the negative effects of air pollution 9,10 . This finding is explained biologically by an immature or low immunological system response and particulate matter entering the respiratory system is expected to have a more acute respiratory effect in susceptible people 11 .…”