hearsay不可靠，peer reviewed journal相对可靠。就你提出的那个论点，其实你把把厨房油烟的关键字拿去google，有非常多的journal论文和政府关于物质毒性的文告有证实其含有致癌物质polycyclic aromatic hydrocarbons和aldehydes

比如这样搜： cooking oil fumes + polycyclic aromatic hydrocarbons + aldehydes

至于抽油烟机有没有用，台湾的论文证实抽油烟机减少肺癌几率50%

https://www.nature.com/articles/s41598-020-63656-7

Impact of cooking oil fume exposure and fume extractor use on lung cancer risk in non-smoking Han Chinese women

Smoking tobacco is the major risk factor for developing lung cancer. However, most Han Chinese women with lung cancer are nonsmokers. Chinese cooking methods usually generate various carcinogens in fumes that may inevitably be inhaled by those who cook the food, most of whom are female. We investigated the associations of cooking habits and exposure to cooking fumes with lung cancer among non-smoking Han Chinese women. This study was conducted on 1,302 lung cancer cases and 1,302 matched healthy controls in Taiwan during 2002–2010. Two indices, “cooking time-years” and “fume extractor use ratio,” were developed. The former was used to explore the relationship between cumulative exposure to cooking oil fumes and lung cancer; the latter was used to assess the impact of fume extractor use for different ratio-of-use groups. Using logistic models, we found a dose–response association between cooking fume exposure and lung cancer (odds ratios of 1, 1.63, 1.67, 2.14, and 3.17 across increasing levels of cooking time-years). However, long-term use of a fume extractor in cooking can reduce the risk of lung cancer by about 50%. Furthermore, we provide evidence that cooking habits, involving cooking methods and oil use, are associated with risk of lung cancer.