Set your priorities, and quickly norrow down the long list of Amazon best-selling air purifiers, into your best three options:

Target features: HEPA-type filter for larger allergens such as dust, dander, and large pollens.
Target features: Efficient True HEPA (or BioGS HEPA) filter for mold spores, dust mites, germs, smoke, small pollens, pet dander and hair, plant spores and fungi, visible smoke; clean air circulation; Air ionizing technology for more efficiency; Certification from the Asthma and Allergy Foundation of America; A higher ACP (Air Change Per Hour); AHAMs (The Association of Home Appliance Manufacturers) CADR (Clean Air Delivery Rate) certification.
Target features: UV sanitizer; Photocatalytic oxidation technology; Air ionizing technology (or preferably PlasmaWave technology which does not emit ozone); A higher ACP (Air Change Per Hour); AHAMs (The Association of Home Appliance Manufacturers) CADR (Clean Air Delivery Rate) certification.
Target features: Anthracite Carbon filter (or Coconut Shell Activated Carbon or Activated Charcoal filter) for chemical pollutants such as, smoke, chemical fumes, different types of odor, VOCs in paint and cleaning supplies; A higher ACP (Air Change Per Hour); AHAMs (The Association of Home Appliance Manufacturers) CADR (Clean Air Delivery Rate) certification.
Target features: Night-time settings; Quiet fan, or efficient fanless technology such as ionic filtration; Night-light.
Target features: Filter service indicator; Robust controls; Air quality monitoring system and smart automatic adjustments; Timer; Air quality monitor; Remote control or app-controlled capabilities; Easy filter replacement; Ability to activate/deactivate filters in the device.
Target features: Convenient/compact design; Less weight; Well-designed handle; Casters for larger models.
Target features: Lower price on the device; Permanent (washable) filters or extended filter life; Pre-filtering; Cheaper filters; Availability of generic filters; Energy efficient (Energy Star); Automatic shutdown when the air is clean.
genuFIND only focuses on highly rated products. Yet, a 5 star product with 1000 ratings is more credible than a 5 star product with 100 ratings.

Your room size is:

sq.ft.