Abstract: ObjectiveTo assess the effects of continuous heavy hazy weather occurred in December 2012 and January 2013 on daily life and health of residents in Jinzhou district of Dalian city and to provide reference for making intervention measures.MethodsA face-to-face questionnaire survey was conducted among 2 163 residents aged over 18 years selected with stratified cluster random sampling in Jinzhou district of Dalian city.ResultsFor the 2 163 participants during the heavy haze episode,58.8%and 57.7%reported decreased outdoor activity and physical exercise; 19.5%and 21.7%reported irritation of the throat and cough; 11.2%and 10.4%reported taking medicine and visiting a doctor due to respiratory illness; 9.7%and 8.6%reported taking medicine and visiting a doctor because of cardiovascular or cerebrovascular diseases; and 20.1%reported closing the windows.The scores of the heavy hazy infulence on perceived affection on daily life,irritation symptoms,medical consultation or medicine use,and coping behaviour were 2.54±1.91,0.98±1.11,0.40±1.03,and 1.59±0.75,respectively,with positive relationships among these scores based on the results of partial correlation analyses (correlation coefficients: 0.080-0.403.P<0.001 for all). ConclusionContinuous heavy hazy episode increases the incidence of respiratory and other mucosa irritating symptoms significantly and the patients with respiratory or cardiovascular diseases are more vulnerable to heavy air pollution.