High concentrations of air pollutants such as total suspended particulates (TSP) and sulfur dioxide (SO2) have serious impacts on nearby populations. In this paper, a survey of rural Tianjin residents' willingness-to-pay for health improvement was reported on, and the MBDC (multiple bounded discrete choice) model was adopted to study the respondents' willingness-to-pay to prevent respiratory illnesses. The results showed that the willingness-to-pay for health improvement was affected by respondents' health condition, work situation and environmental awareness, but not by personal habits, such as smoking. If person's willingness-to-pay to avoid respiratory diseases can be considered equal to the cost to personal health caused by air pollution, the total cost will reach 538 x 10(6) RMB Yuan (RMB, equal to 65 million USD) per year.