While it might be a bit late to ask that question, the question is still valid. The original mission of environmental regulatory agencies with respect to air pollution was to identify and control obviously toxic substances, produced by industrial or mobile sources. Thus, carbon monoxide, sulfur dioxide, hydrogen sulfide, and a host of others can be unequivocally identified as "pollutants."
In the case of carbon dioxide, however, the brain trust has confounded cause and effect, and lie about both: They posit an effect--global warming--and assign without any proof a proximate cause, carbon dioxide. This argument is even weaker now, as global warming has recently morphed into "climate change," as the so-called data supporting warming keeps evaporating.
While carbon dioxide can never be toxic--strictly speaking it will act as a "simple asphyxiant" in high concentrations--it is essential for plant life, and is a waste metabolite of all animals.
The plain fact is that there is no science anywhere supporting the spurious notion that carbon dioxide is a pollutant. If it is, then so is oxygen, which itself becomes extremely dangerous at concentrations above 23%. At that concentration and above, many materials will either spontaneously combust, or burn much more readily than at normal conditions. Talk about real global warming!
Fortunately, our current atmosphere is 21% oxygen.
Better not plant any more trees, or they might pollute the environment with oxygen!