Mining of the association rules between industrialization level and air quality to inform high-quality development in China

It is an urgent challenge to coordinate industrialization and air quality in China since the rapid industrialization over the past forty years caused serious air pollution. In this paper, we measured the industrialization levels of the 31 regions in China from 2003 to 2017 as a sum of per capita gross domestic product (GDP), urban population (% of total), tertiary vs. secondary industry output ratio, non-agricultural output value (% of GDP), non-agricultural employment proportion, and the proportion of added value of manufacturing in the total added value of commodity. We measured air quality as a sum of annual SO2, NO2 and PM10 concentrations. In general, the industrialization level continuously increased while air pollution was reduced in spite of some fluctuations in China. Our results show air pollution presented N-shape relations with the industrialization level in China in the periods from 2003 to 2008, 2009 to 2013, and 2014 to 2017. Air pollution increases as the industrialization occurs but later deceases as the industrialization level improves. However, air pollution rebounds as the industrialization moves further but this rebound became weaker in recent years. With the association rule mining, we identified ranges of the six indicators for industrialization associated with good and poor air quality, respectively. Using industrialization indicators associated with poor air quality as references, we pointed out differentiated strategies for regions to coordinate the industrialization and air quality protection.