CNR - National Research Council of Italy, Research Institute on Sustainable Economic Growth, Collegio Carlo Alberto, Via Real Collegio, 30-10024 Moncalieri, Torino, Italy; Yale School of Medicine, 310 Cedar Street, Lauder Hall, New Haven, CT 06510, USA.
Sci Total Environ. 2020 Aug 10;729:138474. doi: 10.1016/j.scitotenv.2020.138474. Epub 2020 Apr 20.
This study has two goals. The first is to explain the geo-environmental determinants of the accelerated diffusion of COVID-19 that is generating a high level of deaths. The second is to suggest a strategy to cope with future epidemic threats similar to COVID-19 having an accelerated viral infectivity in society. Using data on sample of N = 55 Italian province capitals, and data of infected individuals at as of April 7th, 2020, results reveal that the accelerate and vast diffusion of COVID-19 in North Italy has a high association with air pollution of cities measured with days exceeding the limits set for PM (particulate matter 10 μm or less in diameter) or ozone. In particular, hinterland cities with average high number of days exceeding the limits set for PM (and also having a low wind speed) have a very high number of infected people on 7th April 2020 (arithmetic mean is about 2200 infected individuals, with average polluted days greater than 80 days per year), whereas coastal cities also having days exceeding the limits set for PM or ozone but with high wind speed have about 944.70 average infected individuals, with about 60 average polluted days per year; moreover, cities having more than 100 days of air pollution (exceeding the limits set for PM), they have a very high average number of infected people (about 3350 infected individuals, 7th April 2020), whereas cities having less than 100 days of air pollution per year, they have a lower average number of infected people (about 1014 individuals). The findings here also suggest that to minimize the impact of future epidemics similar to COVID-19, the max number of days per year that Italian provincial capitals or similar industrialized cities can exceed the limits set for PM or for ozone, considering their meteorological conditions, is about 48 days. Moreover, results here reveal that the explanatory variable of air pollution in cities seems to be a more important predictor in the initial phase of diffusion of viral infectivity (on 17th March 2020, b = 1.27, p < 0.001) than interpersonal contacts (b = 0.31, p < 0.05). In the second phase of maturity of the transmission dynamics of COVID-19, air pollution reduces intensity (on 7th April 2020 with b' = 0.81, p < 0.001) also because of the indirect effect of lockdown, whereas regression coefficient of transmission based on interpersonal contacts has a stable level (b' = 0.31, p < 0.01). This result reveals that accelerated transmission dynamics of COVID-19 is due to mainly to the mechanism of "air pollution-to-human transmission" (airborne viral infectivity) rather than "human-to-human transmission". Overall, then, transmission dynamics of viral infectivity, such as COVID-19, is due to systemic causes: general factors that are the same for all regions (e.g., biological characteristics of virus, incubation period, etc.) and specific factors which are different for each region and/or city (e.g., complex interaction between air pollution, meteorological conditions and biological characteristics of viral infectivity) and health level of individuals (habits, immune system, age, sex, etc.). Lessons learned for COVID-19 in the case study here suggest that a proactive strategy to cope with future epidemics is also to apply especially an environmental and sustainable policy based on reduction of levels of air pollution mainly in hinterland and polluting cities- (having low wind speed, high percentage of moisture and number of fog days) -that seem to have an environment that foster a fast transmission dynamics of viral infectivity in society. Hence, in the presence of polluting industrialization in regions that can trigger the mechanism of air pollution-to-human transmission dynamics of viral infectivity, this study must conclude that a comprehensive strategy to prevent future epidemics similar to COVID-19 has to be also designed in environmental and socioeconomic terms, that is also based on sustainability science and environmental science, and not only in terms of biology, medicine, healthcare and health sector.
本研究有两个目标。第一个是解释 COVID-19 加速扩散的地理环境决定因素，这种扩散导致了大量死亡。第二个是提出一种策略，以应对类似于 COVID-19 的未来传染病威胁，这种病毒在社会中的传染性很强。本研究使用了意大利 55 个省会城市的样本数据和截至 2020 年 4 月 7 日的感染人数数据，结果表明，意大利北部 COVID-19 的快速广泛传播与城市空气污染高度相关，这些城市的空气污染程度是通过超过 PM（直径 10μm 或以下的颗粒物）或臭氧设定限值的天数来衡量的。特别是内陆城市，平均超过 PM 设定限值的天数较多（风速也较低），在 2020 年 4 月 7 日感染人数非常多（算术平均值约为 2200 人，每年平均受污染天数超过 80 天），而沿海城市也有超过 PM 或臭氧设定限值的天数，但风速较高，平均感染人数约为 944.70 人，每年平均受污染天数约为 60 天；此外，每年空气污染天数超过 100 天（超过 PM 设定限值）的城市，平均感染人数非常高（约 3350 人，2020 年 4 月 7 日），而每年空气污染天数少于 100 天的城市，平均感染人数较少（约 1014 人）。研究结果还表明，为了最大限度地减少类似于 COVID-19 的未来传染病的影响，考虑到气象条件，意大利省会城市或类似工业化城市每年超过 PM 或臭氧设定限值的天数最多应为 48 天。此外，研究结果还表明，城市空气污染这一解释变量在病毒传染性扩散的初始阶段似乎是一个更重要的预测因素（在 2020 年 3 月 17 日，b=1.27，p<0.001），而人际接触（b=0.31，p<0.05）则不是。在 COVID-19 传播动力学成熟的第二阶段，空气污染会降低强度（在 2020 年 4 月 7 日，b'=0.81，p<0.001），这也是由于封锁的间接影响，而基于人际接触的传播回归系数则保持稳定水平（b'=0.31，p<0.01）。这一结果表明，COVID-19 的加速传播动力学主要是由于“空气污染-人类传播”（空气传播的病毒感染性）机制，而不是“人与人传播”机制。总的来说，像 COVID-19 这样的病毒感染性传播动力学是由系统性原因引起的：一般因素是所有地区都相同的（例如，病毒的生物学特征、潜伏期等），特定因素是每个地区和/或城市都不同的（例如，空气污染、气象条件和病毒感染性的生物学特征之间的复杂相互作用），以及个体的健康水平（习惯、免疫系统、年龄、性别等）。本案例研究中对 COVID-19 的经验教训表明，应对未来传染病的积极策略还包括特别实施一项基于减少主要在内陆和污染城市空气污染水平的环境和可持续政策（这些城市风速较低、湿度百分比高、雾天多），这些城市似乎有一个促进社会中病毒感染性快速传播动力学的环境。因此，在存在可能引发空气污染-人类传播动力学的污染工业化的地区，本研究必须得出结论，必须从环境和社会经济方面制定预防类似于 COVID-19 的未来传染病的综合战略，这也是基于可持续科学和环境科学，而不仅仅是生物学、医学、医疗保健和卫生部门。
