Are you suggesting humans make Co2 from nothing, a little research into were the Co2 human breath out, comes from might show just how silly your question is. In simple term the Co2 in the atmosphere is absorbed by plants, animals eat the plants and we eat the animals (unless your a vegetarian, cut out one step) the Co2 we breath out came from the atmosphere. Fossil fuel on the other hand is Co2 that has been out of the cycle for many millions of years, burning it is a direct addition to the cycle and an increase in over all Co2 levels and why Co2 levels have gone up over 30%.
Carbon dioxide is not 'hazardous to humans'. What is hazardous is the climate change caused by increasing CO2 levels. Only ancient CO2 that is no longer part of the carbon cycle contributes to this increase: exhaling simply replaces the carbon that was taken out of the atmosphere by the food you ate.
Technically CO2 is not "pollution" or "hazardous" as you stated, but if you are in a sealed room and only CO2 is in it, you will suffocate. Not because the CO2 killed you, but because of the lack of oxygen.