Following the coronavirus disease 2019 (COVID-19) pandemic, several studies have examined the possibility of correlating the virulence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19, to the climatic conditions of the involved sites; however, inconclusive results have been generally obtained. Although neither air temperature nor humidity can be independently correlated with virus viability, a strong relationship between SARS-CoV-2 virulence and the specific enthalpy of moist air appears to exist, as confirmed by extensive data analysis. Given this framework, the present study involves a detailed investigation based on the first 20–30 days of the epidemic before public health interventions in 30 selected Italian provinces with rather different climates, here assumed as being representative of what happened in the country from North to South, of the relationship between COVID-19 distributions and the climatic conditions recorded at each site before the pandemic outbreak. Accordingly, a correlating equation between the incidence rate at the early stage of the epidemic and the foregoing average specific enthalpy of atmospheric air was developed, and an enthalpy-based seasonal virulence risk scale was proposed to predict the potential danger of COVID-19 outbreak due to the persistence of weather conditions favorable to SARS-CoV-2 viability. As an early detection tool, an unambiguous risk chart expressed in terms of coupled temperatures and relative humidity (RH) values was provided, showing that safer conditions occur in the case of higher RHs at the highest temperatures, and of lower RHs at the lowest temperatures. Despite the complex determinism and dynamics of the pandemic and the related caveats, the restriction of the study to its early stage allowed the proposed risk scale to result in agreement with the available infectivity data highlighted in the literature for a number of cities around the world.

中文翻译：

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从大气热焓预测SARS-CoV-2天气引起的季节性毒力

在2019年冠状病毒病（COVID-19）大流行之后，几项研究检查了将导致COVID-19的重症急性呼吸综合征冠状病毒2（SARS-CoV-2）的毒力与气候条件相关的可能性。涉及的地点；但是，总体上没有得出结论性的结果。尽管气温和湿度均不能独立地与病毒的生存能力相关，但正如广泛的数据分析所证实的，SARS-CoV-2毒力与潮湿空气的比焓之间似乎存在着很强的关系。在这种框架下，本研究将基于该流行病发生的前20-30天进行详细调查，然后对30个气候变化迥异的意大利特定省份进行公共卫生干预，此处假设该病毒代表了该国从北到南发生的一切，代表了大流行爆发之前COVID-19分布与每个站点记录的气候条件之间的关系。因此，建立了流行初期的发病率与上述大气平均比焓之间的相关方程，并提出了基于焓的季节性毒力风险量表，以预测由于COVID-19暴发而引起的潜在危险。持续存在有利于SARS-CoV-2生存能力的天气条件。作为早期检测工具，提供了以耦合温度和相对湿度（RH）值表示的明确的风险图，表明在最高温度下相对湿度较高的情况下会出现更安全的状况，最低温度下的相对湿度较低。尽管大流行的确定性和动态性以及相关警告很复杂，但由于研究局限于早期阶段，因此建议的风险等级与文献中突出显示的世界上许多城市的传染性数据一致。