Indoor air pollution in developing countries is a public health problem deserving of urgent attention. The aim of this study was to assess indoor second-hand smoke (SHS) exposure via PM2.5 (fine particles with diameter <= 2.5 mu m) level measurements in several public venues in Kuwait. The PM2.5 mean, median, and interquartile range (IQR) values for nonsmoking areas were; respectively, 28, 24, 32 mu g/m(3) while the corresponding values for smoking areas were 274, 222, 288 mu g/m(3) in the absence of water pipe usage and 1434, 1001, 964 mu g/m(3) in the presence of water pipes, respectively. Differences among the three tested venues (nonsmoking, smoking with and without water pipes) were statistically significant (F = 330.7, P < 0.001). The air quality index (AQI) results showed that nonsmoking areas were mostly classified as either "Good" or "Moderate" whereas the classification in smoking areas varied between "Moderate" to "Hazardous." Adverse health outcomes from exposure to PM2.5 were also evaluated. The estimated lifetime lung cancer and cardiopulmonary risks in nonsmoking area were 4 x 10(-3) and 3 x 10(-3), respectively. In smoking areas, the risks were more than sixfold and 30-fold increases of cancer and cardiopulmonary relative to nonsmoking areas without and with water pipes, respectively. In smoking venues, the relative ratio values were 1.26 and 1.16 with no water pipe and 1.86 and 1.51 when water pipe usage was observed, for lung cancer and cardiopulmonary mortality, respectively. These values reveal that people, especially the young and elderly, occupying or visiting these venues are susceptible to lung cancer and cardiopulmonary mortality. (c) 2018 American Institute of Chemical Engineers Environ Prog, 38:e13096, 2019