Environmental pollution, especially air pollution, is an alarming issue for the public, which is extensively debated among academic scholars. During the winter heating season, “smog” has become somewhat a normal phenomenon to local residents’ livelihood in northern China. Based on the daily air pollution data of regional cities in China from 2014 to 2016, and using a regression discontinuity design (RDD), the study finds that winter heating makes the air quality worse in the northern part of China. With the start of the winter heating, it increases the Air Quality Index (AQI) by 10.4%, particulate matter smaller than 10 μm (PM10) by 9.77%, particulate matter smaller than 2.5 μm (PM2.5) by 17.25%, CO by 9.84%, NO₂ by 5.23%, and SO₂ by 17.1%. Furthermore, dynamic changes demonstrate that air quality has gradually improved due to a series of heating policy changes implemented by the central government in recent years. Specifically, from 2014 to 2016, major indicators measuring the air pollution decrease dramatically, such as AQI by 92.36%, PM10 by 91.24%, PM2.5 by 84.06%, CO by 70.97%, NO₂ by 52.76%, and SO₂ by 17.15%.

This study investigates the effects of high-speed rail (HSR) on China’s air passenger transport from the perspective of airports. The difference-in-differences approach is used with unbalanced panel data of 206 airports over the period from 2006 to 2015. Our estimation results found that the negative effects of HSR on the growth rate of China’s air passengers is both statistically and economically significant. However, these adverse effects are not catastrophic.

How does the state choose between direct and indirect governance during wartime? Using the 70-year Dzungar-Qing War (1688-1758) as an exogenous shock and a difference-in-differences strategy on prefecture-level panel data, we reveal that for the Qing Empire, southern resource-rich regions were more likely to shift from local autonomy to direct governance after the war started on northwestern borders. The shifts were more likely to occur where resource transportation was more convenient, while resource-rich areas opened more factories during rather than after the war – all of which highlights the demand for strategic resources as an important determinant of governance paradigm shifts.