During summer,PM 2.5 concentrations positively correlated with stovetop frying (r=0.47)and cooking activity(r=0.41). Higher concentrations were found in homes reporting more cigarettes smoking. BC correlated with time spent cooking (r=0.41),and higher absorbance values were found in homes reporting more cigarettes smoking. Potential modifiers, such as frequency of open windows (r=0.30)and the 1/0 sulfur ratio (r=0.56)positively correlated with BC.