2021 Air Purifier Selection Guide | Must-buy For Allergies In Season

Update time : 2021-08-25 16:22:54

The air quality is getting worse and worse, the epidemic has not ended yet, and the season of allergies in autumn and winter...I saw news reports that harmful dirty air can easily induce asthma and allergies in children, so I really have to start doing my homework seriously and place an order quickly. An air purifier protects the health of the whole family.

What is an air purifier?
Air purifier, also known as air purifier, English Air Purifier, refers to a machine that can filter out air pollutants and effectively improve air cleanliness. Its fan + air filter system can circulate the indoor air, remove and adsorb various pollutants through the filter, and achieve the effect of cleaning and purifying the air.
Function of air purifier
Mainly can purify two major harmful pollutants:
• Particulate pollutants
PM2.5, dust particles, pet dander, pollen, cigarette smoke and all bacteria and microorganisms
• Gaseous pollutants
Formaldehyde, benzene, formaldehyde, xylene, TVOC, sulfur dioxide, nitrogen dioxide, etc.

The American air purifier rating system is MERV, which represents the lowest efficiency rating, ranging from 1 to 18. The MERV value of 17, is the most common grade of household HEPA air purifiers, which can effectively remove tiny suspended particles in the air.
• The MERV value is 1-4, which is a general dust and hair filter.
• The MERV value is 9-13, which can filter smaller particles with better filtering effect and higher efficiency.
• The MERV value of 18 is the highest rating, also known as ULPA, and the system cost is more than $1000. It is used in biological research and hospital air circulation to protect against bacteria and viruses, which is relatively rare in the market.

Segmented by "Type of Filtering Technology"
The filtering technology of air purifier is roughly as follows. At present, most of the air purifiers on the market adopt "composite type", which combines a variety of purification technologies and material media. Here is a breakdown of the air purification technology, and a direct analysis of the advantages and disadvantages of various types of filters:
HEPA air purifier
The HEPA filter is a pleated mechanical filter that can capture suspended particles floating in the air. Please look for the HEPA filter, with its help, the particles in the air can be effectively filtered.

advantage:
• Remove suspended particles floating in the air (such as: dust, pollen, pet dander, smog particles, etc.)
• No ozone is produced, and no harm to the environment.
Disadvantages:
• The HEPA filter cannot eliminate odors.
• A high-quality HEPA filter with a MERV value of 17, relatively generates white noise.
Remarks: HEPA filters are classified into E10 to U17 grades, with filtration efficiency ranging from 99.75% to 99.99%.

According to the US Department of Energy, the HEPA filter should filter at least 99.97% of air particles with a diameter of ≥ 0.3 microns (µm). Source Wikipedia
Electrostatic Air Purifier
The use of electric charge to remove particles in the air is similar to the principle of electrostatic dust removal.

advantage:
• Permanent purification, no need to replace the filter; quieter operation; can remove peculiar smell.
Disadvantages:
• The dust removal effect is poor, and it is less effective for patients with allergies and asthma.
• In the MERV air purifier rating, it is regarded as the lowest level of MERV1.
• Will produce secondary environmental pollution, such as ozone and other harmful gases. (Stimulates the lungs)
Ionic Air Purifier
Negative ions are common in the black technology of hair dryers, but I didn't expect to be able to help in air purification! Dissipate charge into the air, and through the principle of positive and negative attraction, after the positive and negative ions are combined, they fall into a non-toxic form, and the effect is very limited.

advantage:
• Can effectively remove odor molecules. Small size and basically no noise.
Disadvantages:
• In the MERV air purifier rating, it is regarded as the lowest level of MERV1.
• "May" produce ozone. Although ozone helps decompose pollutants, it irritates the lungs and further worsens asthma.
Activated Carbon Filters
Most air purifiers on the market focus on intercepting suspended particles such as dust and pollen, and their effect on deodorization is limited. With the aid of activated carbon filter, it can absorb odor, second-hand smoke, kitchen fumes, etc. The filter is only effective if it needs to be replaced once every three months.
It should be noted that the activated carbon filter is not effective for all gases (such as: formaldehyde). It will not work well in humid environments. At the same time, particles cannot be removed, and it is generally used to assist HEPA filters.
UV Air Purifier
UV-C light is called germicidal light. When buying an air purifier, you can regard the UV lamp as an auxiliary to the HEPA air purifier, but it is by no means the main function of cleaning the air.

Key points for purchasing air purifiers
As ordinary consumers, it seems that every machine is effective when looking at the product introduction. It is too professional and difficult to understand. We know the big points. It is recommended to list first: the main needs, budget, the number of pings in the home, etc., and choose it after comprehensive consideration.
Select models according to the size of the space
CADR (Clean Air Delivery Rate), the air purification output rate, represents how many cubic feet of clean air the machine can produce per minute. The higher the value, the better the purification effect.
According to international standards, it is excellent to purify indoor air 5 times within an hour! It is recommended to choose a model with a clean air range larger than the overall space. It is quite convenient to buy here in the United States, just pay attention to the size of the applicable space. (Example: Room coverage 434 sqft.)

Noise level
The faster the purification speed, the faster the wind speed, and the higher the noise. Therefore, if the machine is placed in a room, pay attention to whether it has a sleep mode. Attention! The larger the CADR, the better, but it also means that the air volume is large and the sound will be louder.
Inlet and outlet position
It is recommended to choose the model with "wind in from below and air out from above". This kind of air duct design is the most scientific, it can ensure high CADR value without high power, and the noise can be relatively reduced. (The patented technology of each brand is different, here is a general recommendation)
Filter / filter replacement cost
The filter must be replaced every 3-6 months to get the best air purification effect. This also means that when you spend money to buy an air purifier, you must also consider the cost of filter replacement.

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