Cooking fumes and secondhand smoke may be responsible for a rising incidence of lung cancer in China’s nonsmoking women, the Ministry of Science and Technology’s newspaper reported Thursday.

The article follows a report published earlier this year by the National Cancer Center, the Ministry of Health’s cancer prevention arm, saying that lung cancer is now the most common form of cancer nationwide. According to the study — which collected cancer registry data on over 300 million people across 31 provinces, municipalities, and autonomous regions — there were an estimated 3 million new cancer diagnoses in 2014, the last year for which health and demographic data is available.

More and more of these new cases involve lung cancer in female nonsmokers, according to Science and Technology Daily, the ministry’s official publication, throwing a wrench in the pervasive belief that people who don’t smoke need not worry about lung cancer.

“Although smoking is a major risk factor, there’s still a chance that those who don’t smoke could develop lung cancer,” Liang Chaoyang, deputy director of the thoracic surgery department at China-Japan Friendship Hospital in Beijing, told the paper. Liang added that nonsmoking women could still get lung cancer by inhaling secondhand smoke.

In China, secondhand smoke kills an estimated 100,000 people each year, and a staggering 70 percent of female nonsmokers report being exposed to secondhand smoke on a daily basis.

Though Science and Technology Daily made no mention of pollution as a contributing factor to lung cancer, the article did suggest a less obvious cause: exposure to cooking fumes such as burning oil.

Zhi Xiuyi, chairman of the lung cancer center at Capital Medical University in Beijing, told the newspaper that China’s “unique cooking methods are a notable contributor to problems that might develop in women’s lungs.” Stir-frying, a common cooking technique in Asian cuisines, can increase the amount of fine particulate matter in the air to a dozen times higher than the healthy range, according to the Science and Technology Daily article. Previous studies in the United Kingdom have shown that cooking on stoves without sufficient ventilation is equivalent to smoking two packs of cigarettes a day.

According to 2015 figures from the Chinese Center for Disease Control and Prevention, 52 percent of all Chinese men smoke, and Science and Technology Daily said that women who live under the same roof with a partner who smokes are twice as likely to develop lung cancer.

Although the Chinese government has a monopoly on the industry in China Tobacco, a state-owned enterprise, and generates revenue from cigarette sales, it has nonetheless taken measures to curb smoking among the general population. In November 2016, Shanghai joined Beijing to ban smoking in office buildings, on public transport, and in some public spaces, with violators being subject to fines.

Editor: David Paulk.

(Header image: Women smoke at a park in Wuhan, Hubei province, Nov. 4, 2012. Sun Xinmin/VCG)