一氧化碳报警器响了，或者一屋子人同时头痛恶心，先出门再打电话

不花钱。

中国疾控的死因监测系统 2018 年报告了 11523 例一氧化碳中毒死亡。最多的是 1 月（2845 例）、2 月（2321 例）和 12 月（2010 例）。冬天这三个月，死在家里的占 66% 到 73%。这是系统里报上来的数，不是按全国人口推算的。美国每年 400 多人死于与火灾无关的意外一氧化碳中毒。10 万人以上进急诊，1.4 万人以上住院

You J, Liu J, Zhou M (2020). Number of Deaths due to Carbon Monoxide Poisoning by Month and by Place of Death — China, 2018. China CDC Weekly 2(2):32：「In 2018, there were 11,523 deaths caused by carbon monoxide poisoning reported in China」. https://doi.org/10.46234/ccdcw2020.008；美国疾病控制与预防中心. 一氧化碳中毒：「More than 400 Americans die from unintentional CO poisoning not linked to fires」「More than 100,000 visit an emergency department」「More than 14,000 are hospitalized」，常见症状「headache, dizziness, weakness, upset stomach, vomiting, chest pain, and confusion」. https://www.cdc.gov/carbon-monoxide/about/index.html；美国消费品安全委员会. 一氧化碳信息中心：「If you suspect CO poisoning, get outside to fresh air immediately, and then call 911」. https://www.cpsc.gov/Safety-Education/Safety-Education-Centers/Carbon-Monoxide-Information-Center

症状像感冒，又像喝多了。一屋子人一起难受、出门就好转，是最强的提示。别留在屋里找原因，别回去关阀门，人先出来再打电话。报警器怎么装见第 1 节第 3 条。