Why Does My Air Purifier Smell Bad? (Causes & Solutions)

Josh Mitchell

Written By

Josh Mitchell

Expert Reviewed By

Holly Curell

Last Updated On

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Key Takeaways

  • There are many types of smells that can emanate from the air purifier. Some of these are temporary, others can remain persistent.
  • Off-gassing and new appliance smells are temporary and will mitigate over time.
  • Musty or sour smell can be a sign of a more permanent cause that needs fixing such as mold, bacterial growth, ozone, or bad air filter.

I couldn’t believe the smell my air purifier was giving off! I bought the air purifier to get rid of smells, not create worse smells! Many air purifier owners just like me experience this frustrating problem, with no idea of what to do next.

But don’t worry, I eventually got everything back to normal and my air purifier is working as it should without stinking up the place.

Below, I’ll go over the potential causes of the unpleasant smell and provide you with effective ways to combat it. So sit tight and get ready to breathe in fresh, clean air once again!

The Causes Of Bad Smells From Air Purifiers And Their Solutions

There are several reasons why your air purifier smells bad, including:

Types Of Smell




Air purifiers with an activated carbon filter are designed to eliminate harmful gases and unpleasant odors from the air. However, these filters can sometimes create a new problem: “off-gassing.” This is when the chemicals trapping the odor in the filter are released back into the air, resulting in a not-so-pleasant smell.

Fortunately, this smell will typically dissipate within a few hours, and high-quality filters are designed to minimize this effect. Running the air purifier on a lower setting or using a HEPA filter can help speed up the process.

Poor Room Ventilation

musty smell from your air purifier may indicate poor room ventilation. Stagnant air can create a “wet dog smell” and harbor high levels of dust, pollen, and other contaminants. In addition to causing unpleasant smells, poor ventilation can also lead to health problems.

Improving air circulation is a great way to eliminate the wet dog smell in your air purifier. To do so, simply open a window or door to allow fresh air to flow into the room. Turning on a fan can also help to circulate the air and eliminate the air purifier smell.

New Appliance Smell

First, empty and clean the water reservoir using mild soap. Use a stronger cleanser for stubborn dirt or mold buildup. Next, rinse the reservoir thoroughly before refilling it with fresh water. Follow the manufacturer’s instructions to clean the filter and replace it if it is filthy. Finally, disinfect the air purifier by running a cycle with a solution of one part vinegar and three parts water. After one cycle, empty and rinse the reservoir.

Switching to a HEPA air filter is often the best solution if the odor persists. These filters effectively capture dust, pollen, and other airborne particles, making them highly effective at eliminating unpleasant smells.


Air filters may emit a distinct odor known as ozone, a gas present in the air we breathe. Ozone is produced when oxygen molecules come into contact with high levels of electrical energy. Although air purifiers use this process to cleanse the air, it’s important to note that excessive exposure to ozone can irritate the lungs and cause shortness of breath.

To eliminate the ozone smell from your air purifier, ensure proper ventilation, regularly replace the filter, and avoid using ozone-producing air fresheners. Additionally, consider using an air purifier with negative ion technology instead of ozone to eliminate this air purifier smell.

Bacteria, Yeast, and Mold Growth

A sour air purifier smell could be due to bacteria, yeast, or mold growth. These organisms are generally harmless in small amounts but can cause a foul smell when present in large quantities. Stagnant water in the air purifier’s reservoir is the most likely cause of their growth. When left standing for too long, water becomes a breeding ground for these organisms.

First, empty and clean the water reservoir using a mild soap. Use a stronger cleanser for stubborn dirt or mold buildup. Next, rinse the reservoir thoroughly before refilling it with fresh water. Follow the manufacturer’s instructions to clean the filter and replace it if it is filthy. Finally, disinfect the air purifier by running a cycle with a solution of one part vinegar and three parts water. After one cycle, empty and rinse the reservoir.

Saturated Activated Carbon Filter

Activated carbon filters are widely used in air purifiers to trap airborne contaminants. As air passes through the filter, the pores in the carbon trap these contaminants. However, as the filter becomes saturated over time, its ability to purify the air decreases, potentially causing stale or unpleasant odors in the air purifier.

If your air purifier produces a weird odor due to a saturated filter, try soaking it in a water and vinegar solution for 24 hours to break down any buildup and neutralize the smell. For air purifiers with multiple carbon filters, rotate them out regularly and ensure they dry completely between uses.

Off-Gassing Plastics

Off-gassing plastics around your air purifier can also cause a bad smell. Chemicals from the plastic can be released into the air, leading to a strong, unpleasant odor. These chemicals can also be harmful to your health if inhaled over a long period of time.

To get rid of the off-gassing odor caused by plastic near your air purifier, remove the source of the smell by relocating your purifier if possible. Alternatively, you can use a HEPA air purifier to lower the concentration of harmful chemicals in the air. Regular cleaning and maintenance of the air purifier can also prevent the accumulation of odor-causing sources.

Faulty UV Light Filter Bulbs

A faulty UV light filter bulb in your air purifier could cause a bad smell. These bulbs are responsible for killing harmful bacteria and viruses in the air. However, when they fail, they can release dangerous toxins, posing a health risk and creating an unpleasant odor in your home.

The UV light bulb inside the air purifier may need to be replaced. If your UV light air purifier is emitting an unpleasant odor, check the manufacturer’s instructions to determine if replacing the UV-C bulb will eliminate the odor.

An Electrical Fault

A burning smell coming from your air purifier could indicate a serious issue with the device’s electrical components. Ignoring this problem can lead to a fire hazard and potentially endanger your safety. It is crucial to take immediate action to diagnose and fix the problem.

First, unplug the air purifier and check for visible damage, such as frayed wires. Tape them up or replace them. Now test the purifier by plugging it in and running it for a few minutes. If the burning smell persists, there may be another issue at play. Try cleaning all of the filters to see if that makes a difference. If the smell continues, seek professional repair.

Related Article: Do UV Air Purifier Work?

People Also Ask (FAQs)

Can a dirty filter make your entire house smell?

Yes, a dirty filter can cause the entire house to smell bad.

Why does my air purifier have a chemical smell?

Your air purifier may have a chemical smell due to off-gassing from an activated carbon filter or the presence of chemicals in the unit.

Do HEPA filters smell?

HEPA filters don’t typically smell because they’re designed to trap air particles matter such as dust, allergens, and other contaminants to improve air quality.

Does an activated Carbon filter smell?

An activated carbon filter won’t have an inherent odor. Some may smell when first used, but it should go away relatively quickly.


After figuring out what was causing my air purifier to smell like a dairy farm on a hot summer day, I sprung into action and made my air purifier smell fresh and clean once again.

With regular cleaning and maintenance, the air purification process will run smoothly and effectively, eliminating any unwanted odors from your living space (including the odors it can create).

You’ll never have to ask “Why does my air purifier smell like that?” again. So don’t let a stinky air purifier ruin your day – take action today and breathe in the fresh, clean air you deserve!

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Josh Mitchell


Josh Mitchell
My name is Josh and I am obsessed with home appliances. From portable AC units to heaters and air purifiers, I enjoy testing, learning and using these devices to improve the air quality inside my family home.

My Favorite Home Appliance?

Midea U Shaped Window Air Conditioner

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