Why a green vacuum cleaner? Because standard vacuums can cause more problems than they solve; they have neither the filtration power nor the special bags needed to trap common respiratory irritants. So they can and often do spread a variety of allergens throughout the house as you vacuum.
To do the job successfully, a vacuum cleaner must have bags that can encapsulate microscopic particles plus a HEPA filter to ensure that mold, pollen, animal dander, and other airborne pollutants stay in the machine and don't get blown back out. We recommend the Nilfisk brand.