We develop an input-output subsystem analysis based on the Ghosh model. Our method analyzes the interrelations in terms of emissions between the different subsystem subsectors and between the subsystem and the rest of sectors of the economy through the decomposition of total emissions into four explanatory components. In contrast to previous subsystem analyses based on the Leontief model, our method considers the emissions of the whole activity of the subsystem and not only those related to its final demand. This is particularly relevant to study the responsibility for emissions of the activity of sectors that produce mainly for other sectors. We apply this method and also the subsystem analysis from the demand-side perspective to analyze the transportation and storage subsystem in Spain in 2014. The activity of the subsystem induced the rest of sectors of the economy to pollute less than the emissions it was induced to emit. There are significant differences between the outcomes from demand- and supply-side perspectives, so that the consideration of both perspectives provides more accurate policy recommendations.