Projecting heat-related cardiovascular mortality burden attributable to human-induced climate change in China.

BACKGROUND: Cardiovascular disease (CVD) has been found to be particularly vulnerable to climate change and temperature variability. This study aimed to assess the extent to which human-induced climate change contributes to future heat-related CVD burdens. METHODS: Daily data on CVD mortality and temperature were collected in 161 Chinese communities from 2007 to 2013. The association between heat and CVD mortality was established using a two-stage time-series design. Under the natural forcing, human-induced, and combined scenarios, we then separately projected excess cause-/age-/region-/education-specific mortality from future high temperature in 2010-2100, assuming no adaptation and population changes. FINDINGS: Under shared socioeconomic pathway with natural forcing scenario (SSP2-4.5-nat), heat-related attributable fraction of CVD deaths decreased slightly from 3.3% [95% empirical confidence interval (eCI): 0.3, 5.8] in the 2010s to 2.8% (95% eCI: 0.1, 5.2) in the 2090s, with relative change of -0.4% (95% eCI: -0.8, 0.0). However, for combined natural and human-induced forcings, this estimate would surge to 8.9% (95% eCI: 1.5, 15.7), 14.4% (95% eCI: 1.5, 25.3), 21.3% (95% eCI: -0.6, 39.4), and 28.7% (95% eCI: -3.3, 48.0) in the 2090s under SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5 scenarios, respectively. When excluding the natural forcing, the number of human-induced heat-related CVD deaths would increase from approximately eight thousand (accounting for 31% of total heat-related CVD deaths) in the 2010s to 33,052 (68%), 63,283 (80%), 101,091 (87%), and 141,948 (90%) in the 2090s under SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5 scenarios, respectively. Individuals with stroke, females, the elderly, people living in rural areas, and those with lower education level would exhibit heightened susceptibility to future high temperature. In addition, Southern and Eastern regions of China were expected to experience a faster increase in heat-related attributable fraction of CVD deaths. INTERPRETATION: Human activities would significantly amplify the future burden of heat-related CVD. Our study findings suggested that active adaptation and mitigation measures towards future warming could yield substantial health benefits for the patients with CVD. FUNDING: National Natural Science Foundation of China.

[Size distribution characteristics of particulate mercury on haze and non-haze days].

With the rapid economic development, China suffers from the severe haze and atmospheric mercury pollution. Particulate mercury transport has an important significance in its global cycle. In order to investigate the distribution characteristics of particulate mercury, 12 degrees Nano-moudi (6.2-9.9 µm, 3.1-6.2 µm, 1.8-3.1 µm, 1.0-1.8 µm, 0.56-1.0 µm, 0.32-0.56 µm, 0.18- 0.32 µm, 0.10-0.18 µm, 0.056-0.10 µm, 0.032-0.056 µm, 0.018-0.032 µm, 0.010-0.018 µm) impactor was used to measure the size distributions of atmospheric particulate mercury on both haze and non-haze days in Shanghai. The results indicated that particulate mercury levels were positively correlated with those of the particles. The average concentration of particulate mercury (0.31 ng x m (-3)) on haze days was 2-3 times than that on non-haze days (0.11 ng x m(-3)). The mass size distributions of aerosols and particulate mercury showed bimodal distributions. The peak shifted from 0.56-1.0 µm and 3.1-6.2 µm on haze days to 0.32-0.56 µm and 3.1-6.2 µm on non-haze days. The particles with aerodynamic diameter smaller than 1 µm which could stay for a long time and transport for a long distance, had higher particulate mercury concentrations. The average contribution of particulate mercury to total PM aerosol were higher on haze days (0.029 ng x µg(-1)) than on non-haze days (0.015 ng x µg(-1)), indicating that secondary particles typically grew faster than mercury during the haze pollution events. The particulate mercury concentration in accumulation mode was 2.06 ng x m(-3) on haze days, while it was 0.55 ng x m(-3) on non-haze days. The large increase of the accumulation mode particles was a main reason for the formation of haze. Emissions from the coal burning as well as road surface dust and dust from long-range transport accounted for the serious pollution on haze days.