To inform family physicians about the health effects of air pollution and to provide an approach to counseling vulnerable patients in order to reduce exposure.MEDLINE was searched using terms relevant to air pollution and its adverse effects. We reviewed English-language articles published from January 2008 to December 2009. Most studies provided level II evidence.Outdoor air pollution causes substantial morbidity and mortality in Canada. It can affect both the respiratory system (exacerbating asthma and chronic obstructive pulmonary disease) and the cardiovascular system (triggering arrhythmias, cardiac failure, and stroke). The Air Quality Health Index (AQHI) is a new communication tool developed by Health Canada and Environment Canada that indicates the level of health risk from air pollution on a scale of 1 to 10. The AQHI is widely reported in the media, and the tool might be of use to family physicians in counseling high-risk patients (such as those with asthma, chronic obstructive pulmonary disease, or cardiac failure) to reduce exposure to outdoor air pollution.Family physicians can use the AQHI and its health messages to teach patients with asthma and other high-risk patients how to reduce health risks from air pollution.