9 Reasons Why Your Air Purifier Smells – And How To Fix It

An air purifier can smell because of a saturated carbon filter, faulty UV light or mold and bacterial growths. Ozone production or broken wiring can also create a smell. New air purifiers or filters will normally produce a smell as the plastic off-gasses.

Has your air purifier recently started giving off a new smell? The smell from air purifiers can be either normal or an indication of a problem. Either way, it’s important to know what the underlying cause is, and how to fix it.

The nature of each smell that an air purifier can make is specific to each problem. This guide explains all the potential causes of a smelly air purifier – and how to fix it.

9 Reasons for a smelly air purifier

Before we get into the list of all the possible smelly reasons, it’s important to know that new appliances give off a characteristic smell. If you have a new air purifier, or you are using one after a long time of it sitting unused, it is normal for it to give off a plastic-like smell, and it will go away with time. 

Here is a summary table that links the type of smell with the reason behind it (keep reading for more details on each problem and how to fix it):

Type of SmellReason
SweetIt is normal and indicates that the carbon filter is working fine The sweet smell is indicative of a problem if it is emitted with a mix of foul odors
SourIf an air filter is placed in an environment that lacks proper ventilation, gasses like formaldehyde are not dispersed effectively, causing sour smell.
Wet / vinegar / bleach / chlorineIt is likely the production of ozone byproducts. If the ionizing pins in an air purifier produce ozone as a by-product, the room may also smell damp
SmokeIt could be because of fault in wiring, carbon filters or HEPA filters, off-gassing plastic.
PlasticNormal in a new appliance
Urine / burning smell / fishIt could be because of fault in the electrical components or wiring

If your air purifier is giving off a smell, here are reasons to look for:

1. New Filter

The ‘new-appliance smell’ is not just limited to a brand new air purifier. Instead, a recently replaced filter can also cause a distinct plastic-like smell.

This can also happen if you haven’t installed a new filter but are using your purifier after a long time of disuse. You will usually experience a plasticky or sweetish scent in this case.


  1. The smell from a new appliance or a new filter is normal and goes away on its own.
  2. Run the air purifier on high fan speed (this gets rid of the smell faster)
  3. If the scent is strong and bothersome, you can use an air freshener to help disguise it.

2. Mold or Bacteria

If the filters in your air purifier are not cleaned regularly enough, contaminants can accumulate in the filter, forming a hard deposit and an environment perfect for mold or bacteria to grow.

Mold and bacterial colonies can grow inside the cleaning system leading to a foul, often musty or wet dog smell.


Cleaning your filters will help get rid of the smell. There are different filters for each model, and you need to check the manual for a detailed guide on which ones you can rinse vs vacuum.

The main filters you may find in almost all models are pre-filter, activated carbon filter, HEPA filter, etc.

Pre-filter and activated carbon filters are washable. Both need to be washed every 3-4 months to prevent clogging or the development of mold. Use a dry cotton cloth to clear off the dust, and then rinse them with warm water. Refrain from using any alcohol wipes, bleach, or soaps in the process.

HEPA filters are generally not washable, but can just be vacuumed or brushed. But some HEPA filters are washable and can be rinsed with room temperature or slightly cold water. Check your manual for special cleaning instructions before washing the HEPA filter. Also, ensure to replace the filters timely to continue enjoying healthy and clean odorless air.

However, if after cleaning some mold or bacteria remains on your filter then it must be replaced.

3. Burnt or Off-Gassing Plastic

A burning smell from air purifiers is a common complaint. If your appliance has a plastic body, it can start emitting a burning odor when the system overheats.

Plastic also has a lot of smells that are from the manufacturing process. When you first use your purifier, the plastic body can start off-gassing these odors, which may come across as a burning smell.

Off-gassing refers to the emission of odors or gasses from the materials of the device.


It is normal for plastic covering to off-gas for a few days. However, this could also be because of an electrical fault in the purifier. This makes it important to inspect for short-circuits or burnt wires if you smell burning plastic.

Since plastic is extra sensitive to heat, it may also start off-gassing if the system is overheated.

If your purifier feels hot on touch, unplug and allow it to cool down before turning it on again. If the problem persists, call a technician to check for any electrical fault in the system.

4. Ozone Production

Many air purifiers produce ozone to oxidize contaminants and remove the smell. Since ozone is a powerful oxidizing agent, it easily reacts with other contaminants in the air to create an odor, and helps get rid of the normal smells around the home.

When a purifier produces ozone there is usually a chlorine-like or chemical-like smell. This type of smell usually spreads across the room as the ozone is released into the air.

You can also experience ozone smell, even if you have a HEPA filter installed in your model that does not use ozone production for air purification.

Ionizing pins in non-ozone producing air purifiers also produce an small amount of ozone as a by-product. If the ozone levels increase to a certain extent due to any fault in the system, it can cause the pungent, chlorine-like (ozone) smell in the room.

You can distinguish between the smell of ozone and that of an off-gassing filter by recognizing the type of smell.


Ensure that you don’t have a model that produces ozone to sanitize the air.

  1. Turn the appliance off, as ozone is a toxic gas and lethal in high concentrations. The ionizing pins may start producing ozone because of a fault in the filtration system.
  2. Call in a technician to fix the issue.
  3. Replace the air purifier of it cannot be mended

5. Saturated Carbon Filter

Many air purifiers have activated carbon filters installed to remove gasses. If you smell smoke in the room it can be a saturated or damaged carbon filter.

Over time, carbon filters become saturated with the trapped gasses and can eventually start emitting them. Apart from a smoky smell, you may also find a mix of different foul odors or a sweet smell in the room, depending on the type of gasses trapped in the carbon filter.


To prevent the filter from getting saturated, all you need to do is clean it regularly or replace it, depending on the type of filter.

  1. For a carbon filter, rinse it with lightly running warm water every 3-4 months. Avoid using detergents or soap as they wash away the charcoal and hence hamper effective filtration.
  2. Refer to your manual and locate the filter. Detach it and rinse thoroughly. Let it dry before assembling the system back.
  3. Vacuum the HEPA filter monthly.

6. Broken or Dirty Wires

Broken or dirty air purifier wires are not only a safety hazard but can also cause odors in the room. Purifiers come with a large number of wires installed that interconnect the different components of the system. If any of these wires frays, it can cause the coating to burn, giving off a smoke or burning smell.


  1. Disassemble the unit
  2. Carefully clean the wires with a dry cloth or as instructed in the manual as part of regular maintenance.
  3. During cleaning, inspect for any damaged or broken wires and replace them immediately.

7. Faulty UV Light

Some air purifiers use a UV light to remove microorganisms. These lights kill harmful pathogens in the air making it safe to breathe.

Any technical fault in the UV light prevents it from effectively removing microbes from the environment and can create a chlorine smell, which pollutes the air.


UV lights, on average last up to 5 years. Any damage to it may impair its functions, and can cause the smell. Also, if your model is old, the UV light may just need replacement after completing its optimal life span.

Either way, you need to replace the UV light for the appliance to resume its functions.

8. Electrical Fault or Burnout

If your purifier is new and gives off a burning smell, poor wiring cocanuld be a reason behind it.

However, if you have had your air purifier for awhile it is likely to be an electrical fault caused by something blocking the proper rotation of the fan, fan burnout or a faulty blower or motor.


Determining the root cause is important to fix any electrical fault, as they are dangerous fire hazards.

Disassemble your purifier and make sure your fan is rotating smoothly when moved by hand. If not, then identify the blockage and remove it to get the system working again. Plug the system in, and check if the motor is working fine. Clean or replace it if required.

Look for any fault in wiring – if this is the case see if you can get a replacement under warranty, otherwise you may need to simply purchase a new air purifier.

If your air purifier is also not working properly, Plentiful Air has more information to help you troubleshoot available here.

9. Off-Gassing Filter

An off-gassing filter is the one that passes volatile organic compounds (VOCs) from the air purifier back into the air. Based on the type and level of volatile compounds or gasses, smells can vary, but you can experience a slightly metallic smell or a strong foul odor.

Some purifiers come with a titanium oxide coating that leads to off-gassing. Usually, this smell goes after a few months of operation. If it does not stop, you may need to replace the filter.


An off-gassing filter is normal for a new appliance. However, if you are not comfortable with the smell, consider buying a HEPA-filter vacuum to clean the filter effectively.

How To Get The Smell Out Of Your Air Purifier

To get rid of the smell coming from an air purifier it depends on the root cause. Cleaning and/r replacing the filters, fixing any damaged wires, and placing the purifier in a properly ventilated space will help remove any odors.

The smell of off-gassing plastic will naturally resolve itself over time.

Refer to the table at the start of the article to identify the exact cause of your smelly problem. You can get rid of the smell from air purifiers in the following ways:

  • Clean all the filters. Maintenance of the appliance is crucial for it to deliver effective performance. Since all the models come with different filters, refer to your user manual and clean or replace the filters as instructed.
  • Inspect for any damage in wiring and replace them if need be.
  • Turn off your air purifier immediately and call a technician if the room smells excessively of ozone (wet, vinegar-like, or bleach-like smell)
  • Certain kinds of smells, like a plasticky new-appliance smell or a sweet carbon filter smell are normal and go away on their own. You may use an air freshener to help with the odor if it feels uncomfortable.

Frequently Asked Questions

Do Air Purifiers Make Your Home Smell Better?

Air purifiers sanitize the air and remove contaminants that can make a room or home smell bad. The removal of odor agents, eventually makes homes smell better. However, air purifiers don’t impart any fragrance to the room.

But they do help by removing the bad odors, by filtering contaminants. Hence, they make the atmosphere in the house smell pleasant.

Is an Air Purifier Supposed to Smell?

It is normal for new air purifiers to give off a plastic-like smell. A slightly sweet smell is also acceptable and indicates a properly functioning carbon filter. Any other odor from the appliance is not normal and needs to be checked.

Air purifiers are only supposed to give off a plastic-like new appliance smell or a slightly sweet carbon filter smell. Any other odor is indicative of a malfunction. Therefore, you need to diagnose the problem and fix it.


There can be various reasons your air purifier could be smelling bad. To put it all simply, it is normal for air purifiers to smell like plastic and this ‘new-appliance smell’ goes away on its own after a few months. You may experience a similar smell after replacing a filter.

Air purifiers can undergo different technical and electrical faults, and each can be identified by the type of resultant smell. A chlorine-like smell for ozone, foul odor for clogged filters, smoke smell due to damaged wires, or off-gassing plastic body to name a few.

Refer to the chart in our post to identify the exact cause of your problem.

Theresa Orr

Theresa Orr holds a PhD in Earth Science and specializes in determining past climates from rocks using geochemistry. Her passion for clean water, soil and air drives her to provide easy to understand information for everyone to read.

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