FAQ

WHAT'S THAT PURPLE DUST?

Notice some purple or brown dust when unboxing your unit?

When your PuraShield products arrive, you may notice a little purple or brown dust while unboxing. That’s because our patented§ filtration media is a unique shade of purple — in fact, that’s where it gets its power.

Learn more about the power of purple.

WHICH UNIT IS RIGHT FOR ME?

Find the right air filtration solution for your space

Figuring out which air filtration solution is best for your space can be confusing. Everything from your current HVAC system, to room size, to the amount of natural ventilation and foot traffic you have in your space can impact your air filtration needs.

We’re here to help. Our product selector makes it easy to determine which PuraShield product and media will work best for you.

WHAT DOES THAT WORD MEAN?

Definitions for terms like CFM, ACH, MERV & more

As you explore our website, you may encounter terms and phrases that you don’t see every day. Here’s a quick rundown of what those terms mean — and why they matter.

INDOOR AIR QUALITY (IAQ)

Indoor Air Quality (IAQ) is just as straightforward as it sounds. It refers to the air quality of an enclosed space in relation to the health, safety and comfort of the area’s occupants. In air filtration, IAQ is most often used in the context of air pollutants that can be hazardous to an individual’s health or quality of life.

HEATING, VENTILATION & AIR CONDITIONING (HVAC)

Your heating, ventilation and air conditioning (HVAC) system is the technology responsible for heating, cooling, circulating and regulating the humidity in your indoor space.

CUBIC FEET PER MINUTE (CFM)

CFM is a measurement of how much air a unit is capable of circulating per minute. For example, the PuraShield 500 has a 250 maximum CFM with its filter in — meaning it can circulate 250 cubic feet of air per minute.

AIR CHANGES PER HOUR (ACH)

Much like CFM, ACH is a measurement of how much air circulation a unit can achieve in a set period of time — but, in this case, it’s an hour instead of a minute, and the size of the room becomes part of the equation.

ACH is a little more complicated than CFM, because how many air changes your unit can achieve per hour is directly impacted by the size (more specifically, the volume) of your space. To calculate air changes per hour, you’ll need three things: The volume of your space in cubic feet (L x W x H), the CFM of your unit and the number 60 (minutes in an hour).

From there, the formula looks like this:

ACH = 60 x CFM / Room Volume

Here's a look at the relative ACH of each PuraShield unit in a furnished, ~1000 ft2 room when running at its max CFM:

PuraShield Unit ACH Chart

HIGH-EFFICIENCY PARTICULATE AIR (HEPA) FILTERS

High-Efficiency Particulate Air (sometimes the A here refers to Arrestance or Absorbing) (HEPA) filters are defined by the EPA as mechanical air filters designed to “remove at least 99.97% of dust, pollen, mold, bacteria, and any airborne particles with a size of 0.3 microns.”

Why 0.3 microns? This is what they call the most penetrating particle size (MPPS) — it’s the most likely to pass through a filter instead of getting trapped. So, if the filter can catch 0.3-micron particles effectively, it’s likely to be even more effective against larger particles.

MINIMUM EFFICIENCY REPORTING VALUES (MERV)

Minimum Efficiency Reporting Values (MERVs) are a measure of how effective a filter is at capturing particles between 0.3 and 10 microns in size. This rating system was created by the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) and has since been adopted by organizations like the EPA and CDC.

MERV ratings are on a scale of 1 to 16 — the higher the MERV value, the more effective a filter is at trapping particulate matter in the 0.3 to 10 micron size range. However, this does NOT mean you should automatically reach for the filter with the highest MERV rating.

Here’s why: A filter with a higher MERV rating generally achieves this by being made of denser material — the denser the material, the more particulates the filter captures. But, the denser the material, the more it restricts the airflow in your HVAC system, too. This forces your HVAC to work harder to achieve the air circulation needed for heating and cooling, meaning it uses up more energy to do its job. The result is higher energy costs for you, more frequent maintenance and potential damage to your system in the long term.

Here are each of the MERV ratings and a brief overview of what they mean:

MERV Ratings Chart

VOLATILE ORGANIC COMPOUNDS (VOCS)

Volatile Organic Compounds (VOCs) are air pollutants that can negatively impact the health of individuals exposed to them.

The EPA defines VOCs as “organic chemical compounds whose composition makes it possible for them to evaporate under normal indoor atmospheric conditions of temperature and pressure.” In simpler terms: VOCs are compounds that can get into the air in normal indoor conditions. Propane, formaldehyde, ethanol and pesticides are all examples of VOCs.

They can come from cars, refineries, paints, air fresheners, aerosol sprays, furniture, wastewater treatment plants and more. VOCs are nearly everywhere, which is why it’s so important to filter them out of the air before they can impact our health, causing adverse effects like:

  • Headaches and nausea
  • Eye, nose and throat irritation
  • Liver and kidney damage
  • Allergic reactions in babies and children
  • Vomiting, dizziness, lung damage and a whole host of other problems

Because VOCs are gaseous by nature (meaning their molecules are extremely tiny), it takes the power of gas-phase filtration to remove them.

GAS-PHASE FILTRATION

Gas-phase filtration refers to the removal of harmful, nuisance and toxic gases from the air. This includes the VOCs we talked about above, which can be produced by the equipment and processes within your facility. PuraShield’s powerful technology removes harmful gases and other contaminants from the air through two different processes — adsorption and chemisorption.

ADSORPTION

In air filtration, adsorption is when particulate matter and contaminants in the air become attached to a filter. In this process, particles are sucked into the filtration unit and become “stuck” to the surface of the filter.

In PuraShield units, these particles are “trapped” upon removal — meaning that they won’t be re-released into the air. Less advanced filtration systems may reach a point where their filters have adsorbed the maximum amount of contamination they can hold, which can result in the re-release of harmful particles into the air you breathe.

In the process of adsorption, particles are simply trapped in a filter, but are not destroyed or changed on a molecular level. To do more than just trap contaminants, you need a filtration system capable of chemisorption.

CHEMISORPTION

Chemisorption with SP media is the difference between simply trapping harmful particles and actually rendering them harmless.

As air passes through PuraShield’s patented§ four-stage system, a chemical reaction occurs when gas molecules make contact with the SP filter media. This reaction forms a bond between the molecules and the filter, turning harmful gases into harmless salts through oxidation.

HOW IS MOLECULAR AIR FILTRATION DIFFERENT?

Our powerful molecular filtration media works different from the rest

PuraShield’s patented§ molecular filtration media works a little differently than your average air filtration media — that’s what makes it so effective. Instead of just catching harmful gas molecules (a process called adsorption), it actually changes them on a molecular level (a process called chemisorption). When these molecules make contact with the SP media, a chemical reaction occurs, changing them into harmless salts.

Learn more about PuraShield's technology

HOW DO I REPLACE MY FILTER?

How-tos for swapping out the filters on your unit

We’ve put together a few simple videos to walk you through the process of changing the filters in your PuraShield unit.

500 & HEPA PLUS UNITS

SMART 500 & SMART 1000 UNITS

§Patent number US 9,370,763 B2
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