Figure 1
Figure adapted from Fig. 1 in “Lung cancer risk by geologic coal deposits: A case–control study of female never-smokers from Xuanwei and Fuyuan, China” by Wong et al.17. Adapted with permission.
Map of geological coal deposits and study villages in Xuanwei and Fuyuan counties. Classification of coal regions based on the State Standard of China Coal Classification (GB5751-86); 1/3 coking, coking, gas fat, and meager lean coals are subtypes of smoky coal. *Historic smokeless coal deposit.
