Background: As urbanization progresses, urban built-up areas are expanding, increasing the number of urban heat islands (UHIs) and damaging the cardiovascular health of urban residents. This study aimed to explore the spatio-temporal pattern evolution characteristics of the effect of UHI on cardiovascular diseases (CVDs).
Methods: We analyzed the land surface temperatures (LSTs) retrieved from data from four Landsat remote-sensing images from 1984 to 2017, data on temperature from 95 meteorological stations, and data on CVDs mortality. Based on this, landscape pattern indices were used to analyze the pattern-process-function underlying the effect of UHIs on CVDs.
Results: The effect of UHIs on CVDs increased, thereby increasing the mortality rate by 28.8% and increasing the affected area by 1683.977 km² between 1984 and 2017. The affected areas gradually expanded from the central area of the city, and underwent three evolution stages; the areas highly affected were mainly distributed in the central and southern regions. Patches increased in number, whereas the landscape was fragmented. The area and ratio of high-level patches also showed an upward tendency, increasing the dominance in the overall landscape. The patches of the overall landscape became more complicated in shape, whereas those of high-level ones became less complicated. The degree of concentration of the overall landscape decreased gradually, with the types of landscape patches increasing, reaching a rather even space distribution.
Conclusions: UHIs drastically increase CVDs mortality by increasing temperatures during summer in Beijing, China. As cities expand, the effect of UHIs on CVDs increases in terms of both intensity and area, with overall landscape in uneven distribution, high-level affected areas in point distribution, and low-level ones in large-area concentration. This study, hence, provides theoretical evidence for the prevention and early warning on CVDs.