<p>There is a lack of research on the association between fine particulate matter (PM_2.5) fractions and respiratory disease mortality. Therefore, this study aims to investigate how short-term exposure to fine particulate matter components affects the mortality risk of patients with respiratory diseases.</p><p>We collected data on the number of respiratory deaths and fine particulate matter components, including sulfate (SO₄²⁻), nitrate (NO₃⁻), ammonium (NH₄⁺), organic matters (OM), and black carbon (BC), in Hefei, Anhui Province, between 2017 and 2020. A cross-over case study was used to analyze the association between short-term exposure to PM_2.5 components and the risk of mortality from respiratory diseases. We also stratified by age, sex, and season to reveal whether the effect of fine particulate matter fractions on respiratory mortality varied significantly across populations and seasons.</p><p>A total of 15,878 deaths from respiratory diseases were included. The results showed that every 10 ug/m³ increase in SO₄²⁻, NO₃⁻, NH₄⁺, OM, and BC was associated with the risk of death from respiratory disease during 0–3 days of exposure, respectively (OR values were 1.068, 1.044, 1.067, 1.047, and 1.284, respectively). Short-term exposure to BC contributed the most to the increased risk of death from RD. Stratified results showed that exposure to PM_2.5 components significantly increased the risk of RD death in the elderly, but there was no significant difference at the gender level. The correlation between PM_2.5 components and RD mortality was more extensive in the cold season than in the warm season.</p><p>Short-term exposure to fine particulate matter components does increase the risk of RD death, and the effect is more pronounced during the cold season. This suggests a need to pay close attention to the impact of PM_2.5 composition on patients with RD.</p>