The problems caused by air pollution as a function of bur-ned-over lands in and out of Acre state cause grave injuries to the po-pulation health. Since the burned-over lands cause damages to society, the monetary value mensuration which the same is willing to pay to diminish their impacts constitutes important information to evaluate whether a depolluting project is economically feasible. In general, this research sought to examine the impacts that the ar pollution for fire vegetation has on the Acrean society. Specifically, a) to determine how much society is willing to pay for the decrease in the injuries caused by burned lands, and b) to compare the aggregated willingness-to-pay (WTP) value with the cost of the respiratory morbidity occasioned by the burned lands for the year 2004. The externalities theory was utili-zed to reference this work. The referendum with follow-up was utilized to estimate the benefit for depollution of air of the Acre State. The re-sults show that the dollar applied in internments expenditures for res-piratory morbidity aiming at air bettering brings a benefit of US$ 21.08 meaning that the improvement of this environmental characteristic is economically feasible. At last, the value that society disposes to con-tribute for air improvement in State of Acre can be utilized to finance the development of technologies and rural extension projects and make possible to create objective conditions to the rural producer to incorpo-rate in his productive process an alternative practice to burned lands in the soil prepare for the farming production process.