Air pollution increases the risk for heart attack, stroke, heart failure, irregular heartbeats (arrhythmias) and cardiovascular death. Once inhaled, particulate matter can cause inflammation and irritate nerves in the lungs, starting a cascade of changes that adversely affect the rest of the body, including the heart. The elderly and people with existing heart diseases may be at higher risk from short-term exposure (hours or weeks). Long-term exposure further increases cardiovascular risk and reduces life expectancy, probably by several months to a few years. The American Heart Association recommends people, particularly those at high cardiovascular risk, limit their air pollution exposure.