Long-Term Residential Exposure to Particulate Matter and Its Components, Nitrogen Dioxide and Ozone—A Northern Sweden Cohort Study on Mortality

Abstract

This study aims to estimate the mortality risk associated with air pollution in a Swedish cohort with relatively low exposure. Air pollution models were used to estimate annual mean concentrations of particulate matter with aerodynamic diameter ≤ 2.5 µm (PM2.5), primary emitted carbonaceous particles (BC/pOC), sea salt, chemically formed particles grouped as secondary inorganic and organic aerosols (SIA and SOA) as well as ozone (O3) and nitrogen dioxide (NO2). The exposure, as a moving average was calculated based on home address for the time windows 1 year (lag 1), 1–5 years (lag 1–5) and 1–10 years (lag 1–10) preceding the death. During the study period, 1151 cases of natural mortality, 253 cases of cardiovascular disease (CVD) mortality and 113 cases of respiratory and lung cancer mortality were observed during 369,394 person-years of follow-up. Increased natural mortality was observed in association with NO2 (3% [95% CI −8–14%] per IQR) and PM2.5 (2% [95% CI −5–9%] for an IQR increase) and its components, except for SOA where a decreased risk was observed. Higher risk increases were observed for CVD mortality (e.g., 18% [95% CI 1–39%] per IQR for NO2). These findings at low exposure levels are relevant for future decisions concerning air quality policies.

Effects of low-level air pollution exposures on hospital admission for myocardial infarction using multiple causal models

“…The entire NO 2 association takes place at concentrations below the EPA NO 2 annual standard and again, other recent literature has also reported associations in that range ( Wei et al, 2021 ; Ma et al, 2022 ; Schwartz et al, 2021b ; Crouse et al, 2015 ). Previous results for O 3 have been mixed, as were ours ( Yazdi et al, 2021b ; Cakmak et al, 2018 ; Sun et al, 2022 ; Sommar et al, 2021 ). In general, studies in North America have reported positive effects of O 3 , while studies in Europe have found negative, protective effects.…”

Associations between long-term exposures to airborne PM2.5 components and mortality in Massachusetts: mixture analysis exploration

“…However, there are also studies reported null associations between those components with mortality [ 22 , 23 ]. Some studies have examined NO 3 − , SO 4 2− , NH 4 + together as secondary inorganic aerosols (SIA) and shown associations with cardiovascular mortality but not with all-cause and respiratory mortality [ 24 , 25 ]. Our study also reported a general pattern of greater mortality rate ratio magnitudes for cardiovascular mortality than all non-accidental and respiratory mortality.…”

“…Another advantage of our study is that we have stronger study power by incorporating all deaths in Massachusetts from 2000 to 2015. Many previous studies on long-term PM 2.5 components exposures were cohort studies that identified several thousand deaths during the follow-up [ 18 , 23 , 24 ], or up to tens of thousands of cases [ 17 , 25 ]. In our study, we have included nearly 800 thousand deaths, which provided a much stronger study power than the previous studies.…”

Benefits of future clean air policies in Europe

“…4 Figures 3 and 4 show the mortality results of other recent European studies for long-term PM 2. 5 8-15 and NO 2 , [11][12][13][14][15][16][17][18][19] respectively, which were published after the closing dates of the WHO systematic reviews. The results from these studies are compared with the summary estimates from the WHO systematic reviews (red vertical line) and the summary estimate from the ELAPSE study.…”