Data and latent variables description
The first five variables described below are the indicators of two latent variables (factors) reflecting
changes in international trade intensity (EONOM) and the structure of the economic activity (STRUCT),
The first three variables (TRADE, GDPPC and INTEN) correspond to the factor: ECONOM, the next two
variables (URBAN, INDUST) to the factor: STRUCT.
a) International trade intensity measured as the sum of export and import divided by GDP, in current
US dollars (TRADE).
b) GDP, measured in current international dollars per capita (GDPPC).
c) International trade intensity with developed countries (UNCTAD classification) measured as the
sum of export and import to/from developing counties divided by GDP, measured in current US dollars
(INTEN). It is assumed that this variable measures the level of trade liberalization between developed and
developing countries.
d) Urban population as a percentage of total population (URBAN).
e) The percent of total output of goods and services produced by the industrial sector (INDUST).
It is further assumed that the latent variables, air pollution intensity (AIRPOL) are influenced by the
following three variables:
f) Carbon dioxide emissions (CO2PC) measured in kg per capita.
g) Nitrogen oxides emissions (NOXPC) measured in kg per capita.
Li Baodong and Wu Xiaokun / Energy Procedia 5 (2011) 803–807 805
h) Sulphur dioxide emissions (SO2PC) measured in kg per capita.
Three variables TRADE, GDPPC and INTEN which describe international trade intensity, per capita
income and the level of trade liberalization, two variables URBAN and INDUST which describe the
changes in the structure of economic activity are chosen to reflect a shift from agriculture to industry.
Three gases CO2PC, NOXPC and SO2PC which reflect air pollution intensity are a product, of the fossil
fuel combustion and industrial processes. The gases are measured in per capita terms in order to fix the
scale of measurement of the emissions.
Emission data were taken from the EDGAR 3.2 database 2005. Data on international trade was taken
from UNCTAD Statistics Database. Other data was taken from the World Resources Institute. A sample
of 80 countries was selected, in the 2005, as low and low middle income countries.