Theoretically, three pieces of evidence are needed to determine whether a substance causes cancer: 1) retrospective epidemiological evidence 2) evidence from animal studies 3) evidence from prospective randomized clinical control studies In the case of smoking, for example, epidemiological research studies have found that 80-85% of lung cancers are associated with smoking. You can’t imagine that in the 1930s and 1940s, the medical literature was full of tobacco advertisements and most doctors smoked because it was fashionable. It wasn’t until 1951 that Richard Doll, the “father of epidemiology” in the United Kingdom, was able to tell us that smoking was the most common cause of lung cancer. Sir Richard Doll, the “father of epidemiology,” first authoritatively reported the correlation between smoking and lung cancer in 1951. Interestingly, at first even Doll himself did not believe that smoking caused lung cancer, and the hypothesis that started the investigation was the relationship between smog and lung cancer due to industrial development in the UK in those years. Analysis of the data showed that the prevalence of lung cancer was equally high in urban and rural areas, that air pollution was not the main cause, and that the smoking rate of up to 80% of men in the UK back then was the underlying cause of the rising incidence of lung cancer. The physician’s intuition and good science prompted Doyle to begin a prospective clinical study straight away, and in 1951 all male physicians in the UK (most of whom were smokers and scoffed at Doyle’s hypothesis) received Doyle’s invitation to join the study, and 2/3 of them, 34,439 in total, agreed to do so. In 1957, the British Medical Research Council declared that smoking was the cause of the early twentieth-century surge in lung cancer, and the health minister then announced the groundbreaking research to the world, with his favorite cigarette in one hand and a government document in the other. This began the West’s fierce anti-smoking campaign. At the same time, various animal experiments verified that 50 of the more than 7,000 compounds in tobacco have direct carcinogenic effects. The complete presentation of the above three pieces of evidence makes lung cancer a theoretically clear cause of tumors, and smoking causes 80% of lung cancers. Incidentally, cigars are theoretically more harmful, as they contain 20 times more tobacco than regular cigarettes, and the impermeability of the cigar skin makes the tobacco burn incompletely, producing even more harmful substances. Cigar smokers have a lower incidence of lung cancer than conventional tobacco, mainly because they are mostly landed gentry, maintenance and medical conditions are better. Returning to the topic of haze, to prove its relationship with lung cancer, we need to provide evidence of the above three aspects as soon as possible. Drawing on the results of smoking research, the hazard of haze should be related to the amount of exposure. If haze does cause lung cancer, what is its possible mechanism? Airborne suspended particles range in size from 0.1-100 microns, of which 10 microns can enter the upper respiratory tract, 5 microns can enter the fine bronchi, and about 2 microns (PM2.5) can enter the alveoli, the deepest part of the lungs. The alveoli and its fragility, indicating a mere layer of cells, really delicate to pop and blow, the entry of PM2.5 can directly damage the alveolar wall, leading to a local inflammatory repair response. Studies have shown that inflammation and tumors are closely related, and tumors can be seen as inflammation without healing from a certain perspective. Our organism is renewed every day, and the question of scientists is not only why we get tumors, but the bigger mystery is why we do not get tumors. With tens of billions of strict copies and directed differentiation, any mistake can lead to tumors. The answer lies in the fact that we have a strong immune surveillance mechanism, which, to use an inappropriate metaphor, is like a positive social energy. I never jaywalked abroad, even when there wasn’t a single car at the intersection, and when I returned home I was in shape and weaved between the guardrails of the roads of all colors. Richard Dawkins wrote The “selfish gene” written by Richard Dawkins is often used as evidence of human evil by those of us who are not conscious of it. On the cellular level, tumor cells are brave fighters who break through the shackles of society and realize the ultimate dream of a cell, realizing the value of the individual (individual cell). It is often said that the times make the heroes. The rebels in the Cultural Revolution were just ordinary people in normal life, and the frenzy of the society led to the expansion and loss of control of personal ambition. The local inflammation in the alveoli is the current situation, and the potential mutated cells, which are under the control of the immune system, are the “heroes”. Mist causes local inflammation in the alveoli, and the process of regeneration and repair increases the probability of lung cancer. In conclusion, we should do our little bit to help scientists to prove the relationship between haze and lung cancer as soon as possible.