Right off the bat, I'll put the statement out there that I don't have a lot of faith in social sciences. This is mainly due to my own perception that the opinions of social sciences on any given topic change like the wind blows. In the same stance, you can usually put concrete proof on why natural science have their measurable conclusions. With that in mind, let's look at air pollution. This is an immense topic that I simply do not have the knowledge to tackle on my own, so I can give a brief response based off of two articles about the topic.
First up, the economic debt of $225 billion in lost labor income as the direct result of people who died from the effects of air pollution. This seems very scientific in its findings, but at the same time, it's oddly vague. The $225 billion appears to be how much the global economy (IE - the production and consumption of goods and services) lost in 2013. It's a very intangible idea. Is that money in the form of taxes the government could earn? Losses in sales for businesses? It's vague. That said, $225 billion is a very large number, but not that much if you look at it in a global setting. We have $7.9 billion people in the world. The basic math on that says it's losing $28.48 per person in the globe. That sounds like not much using America as a base, but in other countries, that is a lot of money.
Next we look at how trees are able to handle cutting down on pollution (which doesn't at all factor in to the $225 billion lost to the economy). I don't understand any of the numbers listed, so I can't really explain anything. There are 3 different types of trees described. They also describe the ability to fight pollution in drought season, as well as the best possible water conditions. Some types of trees have great results in perfect water conditions, but perform virtually nothing in droughts. Which type of tree works better for a given area, based off of their climate? And how much does that really effect the $225 billion loss on the global economy, if everything globally was perfect with a tree's ability to "eat" pollution?
This topic appears way over my head, so I can't really speculate any farther than those basic points.
In closing, I lean much stronger on a physical science approach, but at the same time, the volume of information is overwhelming for me.