Studies of the respiratory effects of air pollution in Israel published in peer-reviewed journals have been infrequent. Most empiric evidence relates to the association between air pollution and childhood asthma; other air pollution effects on other illnesses are less thoroughly studied. Our evaluation provides a possible explanation for the quite contradictory results demonstrated in the various studies. Actual effect estimates appear to differ considerably, ranging from no air pollution effect to a reasonably strong association detected between PM10 and asthma. We attribute these discrepancies to different research methodologies and different types of data used in various studies.