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Weed Smoking 1200 Depositphotos 272127304 xl 2015

Best Air Purifier for Marijuana Smoke 2021-monster machine “magic”

As more states legalize cannabis there is more demand for appropriate air purification mainly to minimize odors but also to improve air quality for health benefits. The choice of air purifier for weed smoke should obviously be based on the factors that are best for the health of people in the home. The 2 main health problems are fine and ultrafine particle reduction from burning marijuana and any tobacco. In addition to the health problems there can also be problems with odor and so the air purifier needs to deal with this.

The IQ Air Multigas is the best air purifier for removing weed smoke. It has supreme fine and ultrafine particle removal and arguably the best chemical filter in any consumer air purifier for reducing odor.

The IQ air Multigas is however quite expensive. As discussed below, there are options. The IQ air HealthPro plus would be an excellent 2nd choice. At a lower cost the 3rd choice would be a Coway 400S, which has the highest airflow at the lowest noise. Even more cost-effective is the Winix AM90, highly effective on its top fan speed but not very quiet. On lower fan speeds, the room size it can serve is more limited.

These were chosen having considered many many models across the whole market, the process was as follows in this diagram-

Air purifier selection

For an air purifier for weed smoke there are 2 main areas of concern-

  • Weed odor
  • Health concerns

So because of these concerns the 4 air purifiers in this review stood out as the best options.

1) Weed Odor Concerns

Although weed smoking is legalized in many states not everyone likes the smell. This can occasionally lead to problems. Here are ways of drastically cutting the odor problem-

Air purifier

Air purifiers are excellent in removing marijuana/weed smell. In fact, one reviewer of an air purifier had a boyfriend who smoked cannabis and she found that he complained after the air purifier had been on that there was not enough of a weed smell!

The smell is caused by volatile organic compounds (VOCs) from the weed that are deposited on the walls, ceiling and the flooring. They gradually accumulate with time and slowly evaporate back into the air causing a constant smell.

To remove VOCs, an air purifier needs an activated carbon filter. The compounds are absorbed onto the filter and kept there by weak intermolecular forces/bonds. When the filter is replaced, the absorbed VOCs are throwing the bin along with the filter.

To eliminate weed odor from a grow tent a much cheaper option is to have an in line carbon filter with activated charcoal attached to the exhaust duct of the tent. These are a fraction of the price of an air purifier.

Other Strategies to Limit the Smell of Weed Smoke Odor in Your Home

Smoke Weed Outside When Possible

This is probably the best way to reduce the cannabis odor in your home.

Only Smoke Weed in One Part of the Home

It is easier to control the smell if it is localised to one room. This will limit the number of air purifiers that you need to reduce the odor to one. In contrast, if you smoke in 4 rooms you will need 4 air purifiers.

Smoke a Strain With Less Odor

Strains of marijuana have been cultivated to have particular characteristics, some to produce less odor. Smoking these strains will also help with odor control in the home.

Limit the Amount of Weed That You Smoke

Probably not the most popular option!

2) Health Concerns

Health concerns stem partly from the particle pollution in marijuana smoke. Whenever plant material is burnt, it produces many fine and ultrafine particles, this is seen in wildfire smoke but also applies to cannabis smoke. The smaller the pollutant particles, the more damaging they are for health. So far it seems that the chemical constituents are not as cancer causing as those in tobacco smoke, but there is evidence of long-term lung function changes with regular marijuana use.

So it seems important especially if there are children in the house to have an HEPA air purifier with a true HEPA filter (not “HEPA like, 99% HEPA…) for smoke removal. This form of air filtration is the most effective way of reducing particle count in the air and some filters are even specified to remove ultrafine particles-those with a diameter less than 0.1 um. Further information about the damage to children (and adults) from particle pollution can be found in this article-“The 13 Health Problems From Air Pollution“.

However, children also need protection from the active cannabis chemicals in the secondhand smoke as their brains are developing and potentially vulnerable. So the air purifier will also need an activated carbon filter for smoke removal.

In General the iQair HealthPro Plus or iQair MultiGas are the Best Air Purifiers for Cannabis Smoke

There are only 3 manufacturers that certify their air purifiers ability to remove ultrafine particles (smaller is better)-

UltraFine Particle Removing AbilitySpecified to remove particles down to a diameter of-
iQair air purifiers3nm
Coway-some newer models10nm
Orsani20nm
Table of size of particle removed by air purifier-smaller is better

Here is the amount of activated carbon in the carbon filters for reducing the chemicals in smoke (more is better)- 

Chemical Removing CapacityAmount of Activated Carbon in Filter
iQair Multigas12lb
iQair HealthPro Plus5lb
Orsani EJ1203.5lb* or 1lb
Coway 400S1.5lb
Small cheap air purifier0.1lb
Table of amount of carbon in filter-the more the better

*for the granular activated carbon filter, the pleated carbon filter option has 1lb of “media”

Here is the air flow per decibel (Higher is better)

NoiseAir Flow per decibel at highest speed keeping noise under 50dbAir Flow per decibel with air purifier on highest speed
Coway 400S6.88.2Quietest per unit air flow
Oransi EJ1206.15.6
iQair HealthPro Plus3.45.1Loudest per unit air flow
Noise (db) per unit of air flow (cfm)

With all these machines you can buy generic filters that are much cheaper than the manufacturer’s filters-but you should not buy them. This is because you have no way of being sure that they even work, let alone meet the standards for removing ultrafine particles that the manufacturer specifies. This is a significant issue as you are going to be staking the protection of your health on their air purification.

The best way to use an air purifier for weed smoke also helps influence the choice

The room sizes are calculated on the basis of 5 air changes per hour, this is advised by the EPA as the basic number of air changes needed. An air change is when the whole volume of air in the room has gone through the air purifier. An air purifier delivering 5 air changes per hour to a room should reduce the particle count by 80%. This is the recommended minimum particle reduction specified by the EPA.

So if you have a large room you may wish not to buy technically the best air purifier, but the one that can cope with larger rooms. The alternative is buying 2 or more iQair machines.

Best Air Purifier for Marijuana Smoke (Only up to Room Size 200 sq ft assuming 8ft ceilings)

iQair Multigas (supreme chemical filter specification and supreme particle filter)

The air coming out of this air purifier will be better than any other air purifier on the market. It is specified to remove 99.5% of particles greater than 0.003um, the best particle specification on the market. Its removal of chemical compounds may well be the best on the market as well, there is only one other air purifier that comes close.

No pre-filter cleaning needed, this is quite an advantage as almost all other air purifiers have a type of pre-filter which should theoretically be cleaned every 2-4 weeks.

Pros
  • Very very large carbon filters 100x larger than some cheap air purifiers
  • Specified to remove ultrafine particles down to 3nm
Cons
  • Not the noisiest air purifier but also not the quietest air purifier
  • Running costs relatively high
Best air purifier for smoke-diagram of iQair GC multigas
Diagram of iQair GC Multigas. (Some elements copyright iQair with permission)
Filters
HEPA filterHEPA specified to remove 99.8% of ultrafine particles down to a size of 0.003um
Carbon filter amount of carbon (lb)12 lb so so 100x more than some other air purifiers
Filter Change HEPA (Particles)12 months
Filter Change Carbon (Chemicals)29 months
Airflow
CADR at =<50db (CADR on Maximum) 170 cfm
Maximum Room Size (Noise less than 50db*)262 sq ft
Maximum Room Size (On noisiest setting)462 sq ft

Smart ControlYes smart plug

Power74 W
Weight44 lbs
Dimensions “H x “W x D”28x 15 x 16

Annual Running Cost Electricity ($)$45
Annual Running Cost Filters ($)$285
Total Annual Running Cost ($)$330

All the above are approximate and assume running the air purifier for 12 hours per day on the highest setting that keeps the noise below 35db.

*Most people will not wish to have the air purifier on a setting louder than about 35db for sleeping in a bedroom-you may wish to have a quieter setting than 35db this is just a ballpark estimate for most people. On the other hand, if your room layout allows you to be much further than 6 feet from the air purifier you may find the noise this air purifier makes at top speed is alright. The calculations for room size assume that you have 8 foot ceilings and 5 air changes per hour.

Never run an air purifier on auto mode using the inbuilt sensor. These cannot detect ultrafine particles which are damaging to human health, please see this article.

Second Best Air Purifier for Weed Smoke (Only up to Room Size 262 sq ft assuming 8ft ceilings)

iQair HealthPro Plus (second best chemical filter specification and supreme particle filter)

This air purifier is more affordable than the iQair Multigas and has a better carbon filter than the Coway 400s. It is only suitable for rooms up to 262 sq ft, assuming the room has 8ft ceilings, unless you are very tolerant of noise.

No pre-filter cleaning needed, this is quite an advantage as most air purifiers have pre-filters which should theoretically be cleaned every 2-4 weeks!

iQair Healthpro Plus
iQair HealthPro Plus. (Image copyright iQair with permission)

Advantages

Pros
  • Superb particle filtration-removes of all sizes down to the low ultrafine range-particles as small as 0.003nm
  • Large carbon filter
Cons
  • Not the noisest air purifier but not the quietest
  • Not cheap to buy or run
Filters
HEPA filterHEPA specified to remove 99.8% of ultrafine particles down to a size of 0.003um
Carbon filter amount of carbon (lb)5 lb so 40x more than some other air purifiers
Filter Change HEPA (Particles)15 months for pre filter 48 months for Hyper-HEPA filter
Filter Change Carbon (Chemicals)20 months
Airflow
CADR at =<50db (CADR on Maximum) 170 cfm
Maximum Room Size (Noise less than 50db*)262 sq ft
Maximum Room Size (On noisiest setting)462 sq ft

Smart ControlYes smart plug

Power74 W
Weight35 lbs
Dimensions “H x “W x D”28x 15 x 16

Annual Running Cost Electricity ($)$45
Annual Running Cost Filters ($)$180
Total Annual Running Cost ($)$230

 There is a more extensive review of this air purifier here.

All the above are approximate and assume running the air purifier for 12 hours per day on the highest setting that keeps the noise below 35db.

*Most people will not wish to have the air purifier on a setting louder than about 35db for sleeping in a bedroom-you may wish to have a quieter setting than 35db this is just a ballpark estimate for most people. On the other hand, if your room layout allows you to be much further than 6 feet from the air purifier you may find the noise this air purifier makes at top speed is alright. The calculations for room size assume that you have 8 foot ceilings and 5 air changes per hour.

Never run an air purifier on auto mode using the inbuilt sensor. These cannot detect ultrafine particles which are damaging to human health, please see this article.

Best for Larger Rooms Over 218 sq ft

You could buy 2 or more of the iQair machines for a room but that would be expensive and noisier than the next choice the Coway 400S. Although no choices other than the iQair air purifiers have such good chemical removal.

Coway Airmega 400S (Large rooms and quiet. Average/above average chemical filtration and excellent particle filtration)

It’s special power is the ability to serve very large rooms, up to approximately 624 sq feet according to EPA guidelines (assuming ceiling height of 8 feet), at reasonable noise levels. Also specified to remove ultrafine particles down to 10nm in diameter. It also has a reasonable carbon filter and so it is well suited to reducing the weed smell in large areas.

Best air purifier for smoke
Coway 400S published with the kind permission of Coway Airmega
Pros
  • Great particle filter not quite as highly specified as the iQair machines but 2nd best on the market. It removes ultrafine particles down to 0.01um
  • Enormous but quiet airflow-the best combination of high airflow and low noise on the market
Cons
  • Average/good carbon filter
Filters
HEPA filterHEPA specified to remove 99.8% of ultrafine particles down to a size of 0.010um
Carbon filter amount of carbon (lb)1.5 lb
Filter Change HEPA (Particles)12 months
Filter Change Carbon (Chemicals)20 months
Airflow
CADR at =<50db (CADR on Maximum)290 cfm
Maximum Room Size (Noise less than 50db*)450 sq ft
Maximum Room Size (On noisiest setting)640 sq ft

Smart ControlYes WIFI

Power66 W
Weight25 lbs
Dimensions “H x “W x D”23 x 15 x 15

Annual Running Cost Electricity ($)$40
Annual Running Cost Filters ($)$120
Total Annual Running Cost ($)$160

 Also Good

More Cost Effective Weed Smoke Air Purifier-Winix AM90

Winix AM90

This is the replacement for the Winix 5500 and has the advantage of smart WIFI control.

Pros
  • Will cover rooms of up to 360 sq ft if you are slightly more noise tolerant than average (otherwise up to 194 sq ft). So can be cheap per sq ft depending on your noise tolerance and room size, if your room is large and the air purifier at the other end you will not hear so much noise.
  • WIFI control-very important for mold as explained above
  • Running costs low $70 per year
Cons
  • If you are not slightly more noise tolerant than average the on the next fan speed down it will only serve an area up to 194 sq ft.
best air purifer for mold Winix AM90
Filters
HEPA filterHEPA 13 filter
Carbon filter amount of carbonSmall amount of carbon incorporated into main filter 0.1 lb
Filter Change HEPA (Particles)12 months
Filter Change Carbon (Chemicals)3 months
Airflow
CADR at =<50db (CADR on Maximum)126 cfm (234 cfm)
Maximum Room Size (Noise less than 50db*)194 sq ft
Maximum Room Size (On noisiest setting)360 sq ft

Smart ControlSmart Phone App

Power65 W
Weight15.8 lb
Dimensions “H x “W x D”23.5 x 8.7 x 15.1 inches

Annual Running Cost Electricity$40
Annual Running Cost Filters$80
Total Annual Running Cost$120

How to Use an Air Purifier (Air Cleaner) for Weed-a recap

In one review of studies where air purifiers were used, fine particulate matter was reduced between 23-92%. Bear in mind the EPA recommends a minimum reduction of 80%. So even in experimental studies with training in how to use the air purifiers, most air purifier users failed to hit this target. On the other hand, it shows that air purifiers, when used well, can decrease particle count by 90%. This just emphasizes the importance of how you use the air purifier.

  • Buying an air purifier-the air purifier should have a true HEPA filter, adequate air flow (CADR) at a noise that you can tolerate for long periods. The air purifier should be “smart” that is programmable or capable of being made smart. The most difficult part is buying one with an adequate air flow at a noise that you can tolerate for long periods as most air purifiers are too loud on their maximum fan speed and manufacturers usually do not give data on air flow and noise at lower fan speeds. There is helpful advice about buying an air purifier here-“Buying an air purifier”. Alternatively, just buy the recommendations on this site. If you want the quietest air purifier you may wish to read this article-“Best Quiet Air Purifiers“, if you need one that will remove particles very well but is particularly good at removing chemicals from the air, for example from forest fires, please see this article-“Best Air Purifier for Smoke“.
  • Position the air purifier at least 12 inches from any wall-so that the air coming out of the air purifier joins in with the circulation of air in the room. There is advice about using an air purifier in this article-“How to Use an Air Purifier“.
  • Run the air purifier for at least 30 minutes before entering the room. This is because it takes an air purifier this long to reduce the particle count in the room. So the air purifier that you buy needs to be smart or capable of being made smart by plugging it into a smart plug.
  • Run the air purifier continuously when you are in the room at the highest setting that you can tolerate long term. This is because the higher the setting that you run the air purifier on the lower the particle count in the air will be. There is no lower threshold known below which human health does not improve, so the lower the particle count/PM2.5 the better. Health aspects of particle count/PM2.5 are outlined in this article-“The 13 Health Problems From Air Pollution“.
  • Never run the air purifier using its inbuilt sensor-there are 7 reasons that you should not do this as outlined in this article-“How to Use an Air Purifier“.
  • Always test the air with an air quality meter where you are going to sit at the height in the room where your mouth and nose are. Comparing the measurements before and 45 minutes after switching the air purifier on there should be at least an 80% reduction in particle count as the EPA recommends. Testing that the particle count/PM2.5 is adequately reduced by your air purifier is the most important thing that you need to do. Air quality meters can be brought really quite cheaply eg $25, there is a helpful article about them here-“How to Test Air Quality in Your Home“.

Conclusion

The right air purifier for weed smoke is the iQair MultiGas. However this is an expensive air purifier and the iQair HealthPro Plus has the same particle reducing capacity and almost as good chemical reduction.

So in order of preference and decreasing expense. The best air purifiers for weed smoke are-

  1. iQair MultiGas
  2. iQair HealthPro Plus
  3. Coway 400S-significantly cheaper and better for big rooms
  4. Winix AM90-a very capable machine with a good carbon filter. Noisier for a comparable room coverage the Coway 400S.

All of these air purifiers will markedly improve your indoor air quality but always remember to buy an air quality meter to check that the air purification is adequate. There are some air quality meters as cheap as $25, I have written an article about them-“How to test air quality in your home“.

Do air purifiers eliminate the smell of weed?

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