NCI researchers have conducted a series of studies in Xuanwei County, China, where coal is used extensively for home heating and cooking and lung cancer rates among non-smoking women are the highest in China and among the highest in the world. Using data from a retrospective cohort study, they found that improving home ventilation by installing stoves with chimneys was associated with a large reduction in mortality. In addition, changing from a simple fire pit to use of a portable stove that is lit outdoors was associated with a significant reduction in lung cancer. To quantify the relationship between coal use, polycyclic aromatic hydrocarbons, genetic susceptibility, and lung cancer in this region, NCI researchers are conducting a new hospital-based case-control study of 1,000 cases and 1,000 controls among non-smoking females that has an extensive exposure assessment component.