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of the dead patients suffered from comorbid conditions, and the average age was 49 as reported in the Chinese review (21). The most common and initial sign of COVID-19 is the fever, which it can pass with no complications. Otherwise, the patient will suffer from dry cough, bradypnea, myalgia, vertigo, headache, sore throat, runny nose, chest pain, diarrhea, nausea, and vomiting. After the onset of the disease by 1 week, some cases developed dyspnea and/or hypoxemia (48). In severely affected patients, they progress, some with an acute respiratory syndrome with septic shock, coagulopathy, and metabolic acidosis. Early diagnosis via viral detection must be conducted to patients suffering respiratory distress and acute fever, even without abnormalities in pulmonary imaging (4, 55, 56). In late December 2019, the demographic study reported that the percentages of the symptoms were 98% for fever, 76% dry cough, 55% dyspnea, and 3% diarrhea; 8% of the patients needed ventilation support (3). These percentages were confirmed by two recent investigations of a family cluster or a cluster infected from an asymptomatic individual (57, 58). A demographic investigation done in 2012 illustrated that individual who suffered from MERS had fever (98%), dyspnea (55%), and dry cough (47%) as their main signs, and 80% of them needed ventilation support; these values show that the patients in the MERS study where quite higher than that of patients who suffered from COVID-19. In addition, MERS had a higher lethality rate than that of COVID-19. Diarrhea and sore throat were also recorded with MERS patients at a rate of 26 and 21%, respectively. The frequency of clinical signs associated with SARS was recorded as 99–100% for fever, 29–75% for dry cough, 40–42% for dyspnea, 20–25% for diarrhea, and 13–25% for sore throat, and 14–20% required ventilation support (59). On 14 February 2020, the total confirmed cases of COVID-19 worldwide were 66,576 with a 2% mortality rate. While the total confirmed cases of SARS in November 2002 were 8,096 with a 10% mortality rate (60). In June 2012, the total confirmed cases of MERS were 2,494 with a 37% mortality rate (61). One study showed that the R0 of SARS-CoV-2 was higher than that of SARS-CoV; it was 6.47 for SARS-CoV-2 and ranged from two to four for SARS-CoV (20, 21, 62). Table 2 shows the deaths toll by age, gender, and underlying medical conditions in New York City, USA as of 14 April 2020. Mortality Rate and PM Findings During the beginning of the COVID-19 pandemic, it was challenging to determine which citizens were extremely at hazard. Later, it turned out that the people who traveled to Wuhan city were extremely at an infection hazard, but there is no strict information for the citizens who are visiting the market. The Center for Disease Control and Prevention (CDC) in China released the epidemiological features of COVID-19 epidemics linked with the hazardous aspects of the mortality rate (40). It is known that the manner of the SARS-CoV virus development reflects that humans with an elevated average of ACE-2 receptors can be having an extensive hazard level. The titer of ACE-2 receptors can be associated with race, according to a study that proposed that White and African Americans had lower ACE-2-expressing ratios than the typical Asian male patient (39). Yet, the early study had only eight various persons (African Americans, Whites, and Asian), and it was concluded that these findings are unpractical. In another report of 224 cases affected by bronchial carcinoma, ACE-2 receptor was expressed in tissues (63). Smoking history must be considered in characterizing the susceptible populations; ACE-2 gene expression was considerably increased in smokers. Since in China, smoking men are more than smoking women: 54% of men are smokers, while 2.6% of women are smokers (64). This justifies the remarkable gender difference presented in Chinese hospitals. The COVID-19 epidemic showed that children had a conserved class, yet this protection was due to that they were less likely to visit the Wuhan wet market and they have no symptoms or mild illness, and thus have not been examined. COVID-19 has infected 1-month-old babies (65), most with mild or no symptoms. Female individuals who were infected with COVID-19 during the gestation period did not transmit the disease to their infants. About 1,716 Chinese healthcare employees were affected with the coronavirus; five of them died. This terrible infection happened on the 17th of February 2020 (66). Table 3 shows patients, deaths, and fatality rate by age, gender, and underlying medical conditions for n = 44,672 confirmed COVID-19 cases in Mainland China as of February 11, 2020. Factors Affecting the Spreading and Increased of Mortality of the Virus The WHO believes that coronavirus carriers are infectious 2 days before the onset of the symptoms (23). We, therefore, use 3-day average temperature and relative humidity up to and including the day when the R value is measured, respectively. The mortality rate of pulmonary diseases was elevated and strongly linked with the decreasing temperature (67–69). However, another report clarified that cold, as well as heat, can harm the pulmonary mortality rate (70). Moreover, a concluded report within 30 East Asian countries clarified that the higher the diurnal temperature range (DTR), the higher the mortality risk for pulmonary and cardiovascular affection present (71). In the cold atmosphere, the accumulative hazards of pulmonary and cardiovascular mortality grew with higher DTR rates (72). A time experiment conducted in Shanghai on the influence of DTR on chronic obstructive pulmonary disease (COPD) mortality clarified that, for every 1°C increase in the 4 days for DTR, COPD mortality increases by 1.25% (73). In an in vitro report on the effect of cold on immunity, Luo et al. (74) explained that due to the reduction in the phagocytic ability of macrophages present in alveolus beneath the cold temperature, cold impairs immunity functions (74). Cold air respiration enhances the constriction of bronchus and in turn promotes the tendency for pulmonary infection (75).