Objective To investigate the association between short-term exposure to ambient air pollution and hospital admission for ischemic stroke among older adults. Methods Using clinical monitoring data from China National Health Commission, we identified 124 297 individuals from Guangzhou, Guangdong province, China who were 60 years or older and were admitted to hospital for ischemic stroke in 2016-2019. We used a time-stratified case-crossover design and employed the conditional logistic regression model to investigate the exposure-response association between short-term exposure to air pollution and hospital admission for ischemic stroke. Based on each subject's residential address and pollutant data from its neighboring air quality monitoring stations, we used an inverse distance weighting method to assess individual-level exposure to PM_2.5, PM₁₀, SO₂, NO₂, CO and O₃ on each of the case and control days. Results In single-pollutant models, each 10 µg/m₃ increase of PM_2.5, PM₁₀, SO₂, NO₂, CO and O₃ was associated with a 0.46% (95% confidence interval [CI]: 0.13-1.36%, lag 2 d), 0.66% (1.38-2.93%, lag 02 d), 3.39% (0.07-0.21%, lag 2 d), 1.47% (0.07-0.21%, lag 02 d), 0.06% (0.07-0.21%, lag 02 d) and 0.18% (0.07-0.21%, lag 3 d) increase in odds of hospital admission, respectively. The results of 2-pollutant models showed that the association of exposure to SO₂, NO₂ and O₃ with hospital admission for ischemic stroke remained stable with adjustment for each of the other air pollutants. Conclusions Short-term exposure to ambient air pollution, especially SO₂, NO₂ and O₃, was associated with increased risk of hospital admission for ischemic stroke in older adults.

Ambient fine particulate matter (PM_2.5) is a mixture consisting of a wide range of chemical constituents including carbonaceous aerosols, water soluble ions and inorganic elements, and has become the major air pollutant in most cities in China. Evidence suggests that exposure to ambient PM_2.5 induces damage on the cardiovascular system and can increase risk of the development and mortality of ischemic heart diseases (IHD). However, the effects of exposure to specific PM_2.5 constituents on IHD remain unclear, and its underlying mechanisms are yet to be investigated. Here we reviewed studies investigating the association of short- and long-term exposure to specific PM_2.5 constituents with IHD, which may provide useful clues for future relevant studies.

Objective To quantitatively evaluate the association of short-term exposure to ambient submicron particulate matter (PM₁) with hospital admissions for angina in older adults. Methods A case-crossover study was conducted among 46 687 older adults hospitalized for angina from 2016 to 2019 in Guangzhou medical institutions. Grid data on ambient PM₁ concentrations in Guangzhou were obtained from the ChinaHighAirPollutants (CHAP) dataset. Exposure to PM₁ was assessed according to each subject's residential addresses. Conditional logistic regression model was used to analyze the the exposure-response association between PM₁ and hospital admissions for angina. Results From 2016 to 2019, the average exposure level of PM₁ on the same day of hospital admissions (lag 0) for angina was 21.0 ± 11.5 μg/m³. The results of main model analysis showed that lag 0 day exposure to ambient PM₁ was significantly associated with a higher odds of hospital admissions for angina in older adults. Each 10 μg/m³ increase of PM₁ exposure level was significantly associated with a 1.31% (95% CI: 0.05%, 2.59%) increased odds of angina admissions. Results from a two-pollutant model adjusting for O₃ showed that the association between short-term exposure to PM₁ and odds of hospitalization for angina remained stable. According to the results of the above model, it was estimated that the excess hospitalization attributable to ambient PM₁ exposure accounted for 2.46% (95% CI: 0.09%, 4.76%) of the total admissions in Guangzhou during 2016-2019, corresponding to 1539 (95% CI: 54, 2976) admissions. No significant effect modification on the associations was observed by sex, age, or season. Conclusion Short-term exposure to ambient PM₁ was significantly associated with an increased odds of hospital admissions for angina in older adults.