The main factor that determines the average life expectancy in a region is the level of medical care. Of course, the living environment, genetics, and eating habits all have an impact on life expectancy. You can find that Beijing is known for its haze and has environmental problems. Shanghai people can't live without sugar in their recipes, there is something wrong with their living habits. But in the ranking of average life expectancy across the country, Shanghai is first and Beijing is second. And there's a big gap to pull away from third place.
A serious analysis reveals that the nation's top medical resources are concentrated in these two cities. Almost all of the country's difficult cases last to Beijing and Shanghai's big hospitals to find a specialist to do a checkup consultation, is not willing to. These mega-cities gathered the country's first-class medical talent, they mastered the most advanced medical technology, has the most advanced diagnostic medical equipment, early detection of disease, found early diagnosis, coupled with advanced scientific medical means, the rate of death is reduced, delayed, the average life expectancy of course increased.
Besides medical care, I think the average literacy level and life cultivation of the citizens of these cities will also have an impact on the average life expectancy. The more educated group will be more scientific in their diet, life, and health care, and more active in their willingness to participate in fitness and exercise. It may also be a reason to increase the average life expectancy.
Shanghai-Beijing is at a lower altitude, although its environmental pollution is heavier than that of Tibet and Qinghai. Shanghai and Beijing are on the third step of China's terrain, only a few hundred meters above sea level, and the air is highly oxygenated. Tibet and Qinghai are in the first step of China's terrain, the average altitude of three or four thousand meters. The altitude is high and the air is low in oxygen. Low air oxygen content is not good for the human body, and living for a long time in an oxygen-deficient environment will cause harm to the human body.
This is also an important factor in the low per capita life expectancy in Tibet and Qinghai. In one is that, Shanghai Beijing's city is well equipped with all the facilities, all aspects are at the top level in China. Especially the level of medical care is one of the best in the country. This point, Tibet Qinghai far behind. If Tibet and Qinghai had the same altitude and medical conditions as Beijing and Shanghai, then surely the per capita life expectancy would be longer than these two places.
In summary, what affects human life expectancy is not only the quality of air, but also the living environment. So although Tibet and Qinghai are less polluted, the average life expectancy is much lower than Shanghai and Beijing because of the high altitude and the limited medical care.