Tobacco smoke can trigger asthma attacks. More than 40 percent of children who go to the emergency room for asthma live with smokers. Today is World No Tabacco Day. If you are a smoker, we encourage you to quit smoking. There is free help and resources available by phone, online or mail from the CDC. Call 1-800-QUIT-NOW (1-800-784-8669). Callers are routed to their state quit lines, which offer several types of information and services. For more information about secondhand smoke and asthma, visit our website.