Previous studies have reported that air pollution negatively affects the tourism industry. This paper attempted to answer the following question: among different air pollutants, which one acts as the most adverse factor? The study was based on a sample of panel data covering 337 Chinese cities for the period between 2007 and 2016. Four pollutant indicators were inspected: PM 2 . 5 (particulate matter 2.5 micrometers or less in size), PM 10 (particulate matter 10 micrometers or less in size), SO 2 (sulfur dioxide), and NO 2 (nitrogen dioxide). It was found that PM 2 . 5 had a significantly negative impact on both domestic and inbound tourist arrivals. Regarding the other three pollutant indicators, except for the negative influence of NO 2 on inbound tourist arrivals, no statistically significant impact was found. This study suggests that tourism policy makers should primarily focus on PM 2 . 5 , when considering the nexus between air quality and tourism development. According to our estimates, the negative impact of PM 2 . 5 on tourism is substantial. If the PM 2 . 5 concentration in the ambient air increases by 1 μ g/m 3 (= 0.001 mg/m 3 ), domestic and inbound tourist arrivals will decline by 0.482% and 1.227%, respectively. These numbers imply an average reduction of 81,855 person-times in annual domestic tourist arrivals and 12,269 in inbound tourist arrivals in each city.