Air Purifier Jargon 101: Know These Terms to Breathe Safely

Air purifier and pollution jargon can seem to be endless. AQI, CADR, PM2.5, PM10 VOC, ACH, AHAM, and more. What do all of these weird acronyms mean? In this article, we break down all of the most important acronyms you need to know about air pollution and air purifiers.

Air Pollution Jargon

Air pollution jargon 101


AQI (air quality index) is a way of measuring how bad air pollution is. US AQI is one of the most popular air quality indexes followed. The higher PM2.5 levels are, the higher the AQI value is. AQI is typically updated hourly to represent the latest air pollution situation.

More: Find AQI in my area


PM2.5 is a name for air pollution particulate matter (PM) 2.5 microns in size and smaller. These tiny PM2.5 particles are particularly dangerous because they can enter deep into the lungs and the bloodstream. Due to this, PM2.5 is one of the primary pollutants tracked to measure air pollution. 


PM10, similar to PM2.5, measures any air pollution particulate matter (PM) 10 microns or smaller. This means PM10 includes PM2.5 and some slightly bigger particulates in the air. 

Read More: What is the difference between PM2.5 and PM10?


VOC (volatile organic compounds) are gases that are emitted from a wide range of products and can have serious health effects. These products include paints, furniture, office supplies, and more. Common examples of VOCs that may be present in our daily lives are: benzene, ethylene glycol, formaldehyde, methylene chloride, tetrachloroethylene, toluene, xylene, and 1,3-butadiene.

Read More: What product can help remove VOCs from my home?

Air Purifier and Filter Jargon

Air purifier jargon 101


Clean air delivery rate (CADR) is a key metric in measuring an air purifier’s performance. The higher the CADR, the more clean air an air purifier can clean. Note: CADR can be given in two measurements, m3/hour (cmh) and ft3/minute (cfm).

Read More: What CADR air purifier do I need to clean my space?


Acronym for “high efficiency particulate air” filters. HEPA filters are the gold standard of air filtration and are incredibly effective at capturing almost every size particle. They can capture viruses, bacteria, pollen, PM2.5, allergens, and more. HEPA air filters are the most important component of any air purifier.

Read More: What are HEPA filters and how do they work?


MERV is one of many air filter rating standards. The standard rates a filter’s ability to capture larger particles between 0.3 and 10 microns (µm). ‘MERV’ is an abbreviation for Minimum Efficiency Reporting Value. The standard was created by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE)

HEPA filters are similar to MERV filters but have an even higher standard for particle capture.


CARB stands for California Air Resource Board. All air purifiers in California must be CARB certified. Their website has a list of all CARB-certified air purifiers


Some air purifiers use ionizer technology which shoot out negative ions causing particles to stick to surfaces. But research shows they ionizers can be dangerous and are ineffective.


AHAM stands for the Association of Home Appliance Manufacturers. AHAM is a popular organization for conducting Clean Air Delivery Rate (CADR) testing for air purifiers. An AHAM-certified CADR can give consumers confidence in the accuracy of an air purifier’s reported CADR.


Air changes per hour is a number that represents how many times an hour the total volume of air in a space is replaced with new air. ACH is often used to measure ventilation and to find the right-sized air purifier for a space. 

Read More: ASHRAE recommended air changes per hour (ACH)

Learn More About How to Choose the Right Air Purifier

At Smart Air, we know how confusing it can be to choose an air purifier. Which is the best? So we created a simple four-step guide to choosing the best air purifier.

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