Do Air Purifiers Dry the Air?

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Written By Jamila W.

The primary purpose of air purifiers is to filter out things like dust, pollen, and bacteria to improve indoor air quality. Most air purifiers don’t have any mechanism that’s designed for trapping water or moisture either.

So, to answer the question, does air purifier make air dry? Not really. However, some users still claim that their room feels noticeably drier after they leave the air purifier running for some time. Why is that?

As someone with a complete understanding of how most of these purifiers work, this correlation with humidity got me curious. So, I decided to dig deeper and after a complete examination of the science behind this phenomenon, I’ve found the answer.

With that in mind, in this article we’ll discuss:

  • How do air purifiers work?
  • How they can trap some moisture but it isn’t enough to make a difference.
  • Reasons why it can feel dry near an air purifier.
  • How to reduce this feeling of dryness?
  • How to increase dryness in your room?

What Is an Air Purifier and How Does It Affect Indoor Air Quality?

Air purifiers are appliances designed to clean the air within an indoor space. These purifiers capture air from a room and pass it through filters to remove harmful substances like mildew and bacteria. 

But, Do you really need an air purifier?

Well, yes! Indoor air quality can have a more significant effect on your health than you might think. You can experience issues like irritation in your throat, nose, and eyes in the short term. 

As bad as these may sound, they pale in comparison to the potential long-term impact of bad indoor air quality. These include respiratory diseases, heart diseases, cancer, and more. 

How Does an Air Purifier Work?

Put simply, an air purifier uses a fan to draw air from its surroundings and pass it through various filters. These filters are there to capture most sources of air pollution like dust, pollen, mold, and even microorganisms. 

Once passed through the filters, clean air is pumped back into the area surrounding the purifier. Speaking of filters, there are two types of filters you can find in most air purifier units. These are:

Carbon filters

The main goal of carbon filters is to remove Volatile Organic Compounds (VOCs). These are often gasses emitted from common household items like paint and cleaning supplies, as well as office equipment such as printers and markers/correction pens. 

By removing these harmful gaseous compounds, activated Carbon filters also get rid of their odor. However, this type of air filter is not good at capturing airborne contaminant particles, which is where HEPA filters come in. 

HEPA filters

Also known as High Efficiency Particulate Air filters, HEPA filters are there to remove particles with a size of 0.3 micrometers. These filters are also quite effective at their job.

Research shows that portable air purifiers with HEPA filters can improve air quality 80% more quickly by removing potentially infectious airborne particles.

Do These Air Purifier Filters Dry Air?

While we did say that air purifiers do not make the air dry, that is not technically true. Let me explain.

On the one hand, HEPA filters do not remove water. This makes complete logical sense since these filters only remove particles with a size of 0.3 micrometers while water vapor droplets can be 1-14 micrometers in size. 

Activated Carbon filters, on the other hand, do remove moisture but in a very small amount. You can think of this as “drying the air.” But, this reduction is too insignificant to make any meaningful difference in how the air in your room feels. 

So, why do you feel dry when sitting in a room with an air purifier?

Reasons It Feels Dry Near an Air Purifier

From what we’ve seen, there are three possible reasons it feels drier near an air purifier:

Air circulation

One of the biggest reasons why the air might feel dry in a room with an air purifier is because these purifiers circulate air. This circulating air causes the water from your skin to evaporate faster, making you feel dry.

In situations like these, the air purifier does not remove moisture from the air, and the dryness you feel is from your own skin.

Old filters

Popular manufacturers like Dyson recommend you to change the filters in your air purifier once every 12 months because they get clogged over time. If you don’t replace them in time, the purifier can start releasing the previously captured contaminants back into the air. 

Some of these contaminants — like mold — are common allergens and can lead to an itchy nose, eyes, and throat. This makes it feel like the air you’re breathing is dry. But in reality, your body is just showing the symptoms of an allergy. 

External conditions

The feeling of dryness might not be due to the purifier itself. In short, warm air can hold more water vapor than cold air. So, if the air inside your home is too cold because of winter or indoor air conditioning, the overall humidity levels will be lower as well.

What Is the Ideal Humidity Level?

Too little humidity can lead to dryness on your skin, eyes, and lips, while high humidity levels can cause dehydration, fatigue, and heat exhaustion. So, what is the ideal amount?

The ideal humidity range for households is between 30 to 60% according to the recommendation of the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). On the upper end, relative humidity should not exceed 65%.

How to Make Indoor Air More Humid?

Here are a few things you can try to increase the humidity of indoor air:

Increase indoor temperature

You can increase this temperature by sealing your home and using a heater in winter. In summer, tuning down the air conditioner can also help increase the temperature and consequently the humidity. 

Use an air humidifier

Humidifiers are small devices that increase air moisture levels by spraying water in the form of a fine mist that then spreads throughout your room.

Not only does this prevent your skin, eyes, or throat from drying out, but it also has a positive impact on your respiratory health.

How to Make the Indoor Less Humid?

As we mentioned earlier, very high humidity levels can also be harmful. Here’s how you can reduce them:

Air conditioning

Since cold air can hold less water, you can reduce indoor humidity with the help of air conditioning. Do keep in mind that air conditioning can easily go a bit far in the other direction and lead to dryness, so use it in moderation. 

Using a dehumidifier

Dehumidifiers use a cold coil to condense water out of the air and remove it in a tank below. This can quickly reduce the amount of humidity in the surrounding area. 

These devices can reduce the impact of common allergens like dust, pollen, mold, and especially dust mites that need more than 65% humidity to survive. 

Final Words

From what we’ve learned, it is clear that air purifiers do not dry out the air directly. The activated Carbon filters in these purifiers can absorb some extra moisture but their impact is very insignificant.

Even then, you can still feel dry near a purifier because its fan circulates air which, in turn, dries out your skin and eyes. Plus, external factors like cool air or weather can also affect air humidity.

Just make sure that your indoor humidity levels are between 30 and 60%. A humidifier or dehumidifier can come in handy in this regard. We also recommend the use of an air purifier for removing impurities and harmful particles from the air in your living space.

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