This figure shows six studies that have determine the associ

This figure shows six studies that have determine the association between air pollution concentration in a major city and risk for morbidity & mortality. The X_axis is the amount of pollution index Y_axis is the risk of morbidity or mortality. Which of Hill\'s Criteria does this depict? Relative risks of morbidity and mortality for pollution concentration categories is S_ao Paulo.

Solution

The association between air pollution concentration across a major city has been studied by six different researchers. The effect of pollution on morbidity and mortality is shown in the above given graph. The results of six different studies establish relation between air pollution and morbidity and mortality. Acorrding to Hill criteria, this association depicts the temporality. This is defined as the effect occurs due to a cause and there is a certain time period delay between the cause and effect. Therefore, effect occurs after a delay of the cause. Thus, option 1 is correct.