Research on Influential Factors of PM2.5 within the Beijing-Tianjin-Hebei Region in China

Table 4

The codes of the fifteen initial influential factors.

Name	Code
Population density	IF1
Straw burning amount	IF2
Energy consumption per unit area	IF3
Concrete production per unit area	IF4
Steel production per unit area	IF5
Industrial proportion	IF6
Retained number of automobiles per unit area	IF7
Total length of road per unit area	IF8
Transportation volume per unit area	IF9
Total construction areas per unit area	IF10
New construction areas per unit area	IF11
Road construction length per unit area	IF12
Coal consumption proportion	IF13
Natural gas consumption proportion	IF14
Electricity consumption proportion	IF15