Is the short-term lethal effect of NO2 ignored?Focus on the relationship between short-term exposure to NO2 and tumor death in Shenyang, China

Although related studies have shown that the short-term exposure of NO 2 is associated with all-cause and respiratory mortality, there is still no clear evidence for the effect of NO 2 on tumor death. This study aimed to understand whether the lethal effect of NO 2 air pollution was underestimated in China. We comprehensively estimated the association between mortality and NO 2 concentration and also the population susceptibility differences for whole tumors(C00-D48), lung cancer(C34), gastric cancer(C16), liver cancer(C22), colorectal cancer(C18-C20), breast cancer(C50), thyroid cancer(C73), prostate cancer(C61), bladder cancer(C67) and leukemia (C90.1, C91-C95) in a typical old industrial city in the northeast of China. The generalized linear model showed that the increase of NO 2 concentration was positively correlated with an increase of 0.95% (95% confidence interval, 0.33-1.57%), 1.86% (0.79-2.95%), 2.33% (0.38-4.32%), 2.55% (0.68-4.45%), 16.3% (4.01-30.04%), 11.29% (5.9-16.94%), respectively, in the mortality of whole tumors, lung cancer, liver cancer, colorectal cancer, thyroid cancer, and leukemia in the city of Shenyang. Population susceptibility differences were also significant for the short-term effects of NO 2 on tumor mortality. Young and old persons suffering from leukemia were at more death risk from increased concentration of NO 2 and most of this risk of death can be observed on lag0. However, young adults aged 15 to 65 with all tumors and thyroid cancer, were more susceptible to their effects. Women with total tumors, colorectal cancer, were more vulnerable to die from NO 2 air pollution, and significant risk effects can be observed in lag0-lag6 and lag0/lag4/lag5, respectively. Since WHO has recommended a short-term (24-hour) nitrogen dioxide AQGs level of 25 μg/m 3 , which is more stringent than that of 80 μg/m 3 in the Ambient Air Quality Standard of China. We suggest that the local government should seriously consider guiding legislation and policies of air pollution based on the new WHO Global Air Quality Guidelines, to protect public health with an adequate margin of safety.