Acute effects of air pollution on cardiovascular hospital admissions in the port district of Klang, Malaysia: A time-series analysis

Cardiovascular diseases are recognised as a significant burden on healthcare systems globally. In this study, the acute impacts of air pollution, especially from shipping emissions, on cardiovascular hospital admissions in Klang, Malaysia, a notable port district, are explored. Time-series analysis and Quasi-Poisson regressions, combined with distributed lag non-linear models, were employed to examine the relationships between daily levels of pollutants and hospital admissions for cardiovascular issues. Focus was placed on the pollutants NO2 (nitrogen dioxide), SO2 (sulphur dioxide), O3 (ozone), particulate matters with diameters ≤10 μm (PM10), particulate matters with diameters ≤2.5 μm (PM2.5), and CO (carbon monoxide), with consideration of lag effects up to 7 days. An increment of 10 μg/m3 in NO2 concentrations was associated with a 7.32% increase in cardiovascular admissions on the exposure day, with statistically significant elevations in relative risks at lag 0 were observed for admissions among patients with ischaemic heart disease, those aged less than 65 years, and male patients. At lag 4, an association was identified between O3 levels and an increase in relative risk of 1.0513 for hypertensive diseases. Two-pollutant models further highlighted significant interactions between NO2 and PM10, which influenced overall cardiovascular admissions, admissions due to ischaemic heart disease, and particularly affected patients below 65 years old and males, especially at earlier lags. Additionally, interactions involving NO2 and O3 were noted, impacting overall cardiovascular admissions, as well as admissions among patients aged less than 65 years and male patients. The findings underscore the severe health risks posed by air pollution in port areas, highlighting the urgent need for targeted interventions to mitigate these effects. Stricter air quality regulations in port cities are supported by the results to protect public health.