The smog is here, and you may be struggling to buy a home air purifier again. Which air purifier is best for you and your family?
Goal – to remove PM2.5 quickly
According to China’s Ambient air quality standards, implemented a year from now, the annual average of PM2.5 must not be higher than 15 micrograms per cubic meter, and the daily average must not be higher than 35 micrograms per cubic meter (both first-class standards).
In fact, many cities have annual averages as high as 60-100 micrograms per cubic meter. When there is smog, the daily average in some cities can even exceed 500 micrograms per cubic meter.
We chose air purifiers to quickly remove PM2.5 (fine particulate matter with a diameter of less than 2.5 microns) indoors and create a relatively normal environment for ourselves and our families.
In addition, some air purifiers also have the auxiliary skills of removing formaldehyde, deodorizing, sterilizing or humidifying, and producing negative oxygen ions. Let’s we discuss in the future.
Principle of purification
According to the EPA website, home air purifiers typically use three technologies to remove particulate matter: electrostatic dust collection, ion technology, and HEPA technology. know more on dew.
Electrostatic dust collection is the creation of a high voltage electric field to charge particles in the air and attract them to dust collection plates with opposite charges.
- Ion technology releases charged ions into the air, attached to particulate matter and deposited together on the surface of nearby objects, such as walls, furniture, and curtains.
- HEPA, short for the High-Efficiency Particulate Air Filter, sets layers of fibers that block Particulate matter from passing through by blocking, bumping, and spreading.
Electrostatic dust collection and ion technology may produce ozone pollution. Ozone is harmful to human health and is also an important air pollutant. According to China Environment News, in May and June 2014, ozone was the primary pollutant on more days than PM2.5 in 74 cities across the country. Therefore, I don’t recommend either technique to friends or family.
HEPA technology will increase the working noise in a disguised way, and the filter screen needs replacing regularly, so those who choose this kind of air purifier need to consider the subsequent costs.
Clean air volume
Whether an Air purifier is suitable for your home depends on its Clean Air Delivery Rate (also name as CADR). For example, a product has a clean air volume of 600 cubic meters per hour, which means that it can output 600 cubic meters of clean air per hour and 10 cubic meters of clean air per minute in a certain mode of operation.
When air pollution is high, turning on the air purifier will not make the air in the room clean immediately. Simply put, the clean air from the air purifier constantly mixes with the “dirty” air in the room, making it “slightly cleaner.” Air purifier sucks the “slightly cleaner” air in, and a little clean air comes out again, and the cycle continues until an equilibrium reaches.
If you put a particulate matter detector in the corner of a room, you will find that the concentration of PM2.5 will plot an exponential decay curve over time.
Under the same conditions, the greater the amount of clean air, the more efficient the removal of PM2.5 from the room, and the steeper the exponential decay curve.
Manufacturers usually place their machines in a 30-cubic meter sealed laboratory chamber, fill them with high concentrations of PM2.5, and claim to have removed 99.9 percent of the particles one or two hours after turning them on. This number is actually not of many references.
On THE ONE HAND, 30 CUBIC METRE IS EQUIVALENT TO THE BEDROOM WITH 12 SQUARE METRE BIG (ASSUME STOREY HEIGHT 2.5 METRES), THE ROOM OF AVERAGE FAMILY IS BIGGER THAN IT.
On the other hand, people breathe out carbon dioxide, the room cannot be sealed, so there is a constant stream of “dirty” air seeping in through Windows and doors. Suppose you come home from a busy day and are trying to catch your breath when the air purifier says, “Master, it will be two hours before the air is clear. And you can’t open the window or go to the bathroom.” Aren’t you going to take it back?
So how much clean air is the right amount?
A common recommendation is to divide the value of the maximum clean air volume (measured in cubic meters per hour) by 10 to obtain the maximum applicable area. For example, 600 m 3 / h of clean air will apply in a 60 m 2 room (assuming 2.5 m height).
But in practice, we don’t like to leave the machine running at maximum speed for a long time because of the noise.
So the maximum applicable area may consists of 2, into 30 square meters, which is more in line with the actual situation of the recommended use of the area.
Garbage is full to pour, filter life to change. It is difficult to give a definitive service life for the filters of air purifiers because of the different room sizes in each household, the different running times of the machines, and the different PM2.5 concentrations in each region. This requires manufacturers to design a filter life indicator function. Would rather screen early replacement of a month, also can not be used more than one day. Otherwise, the filter not only work efficiency decreased significantly, but also may breed bacteria, damage the health of the family.
When you buy an air purifier, you can ask the sales staff about the design principle of the filter life indicator. If the other party is concerned about him, or this is the so-called “trade secret”, then the machine’s screen indicator function is reliable to call into question. Do not believe some manufacturers for the life of the filter exaggerated propaganda. Two days ago, I saw an imported air purifier in a neighbor’s house that claimed its filters would last up to 10 years.
If YOU PLAN TO USE IN THE SITTING ROOM, IN VIEW OF ITS DOORS AND Windows A LOT OF, AIRTIGHT SEX IS WORSE THAN THE BEDROOM, APPLICABLE AREA MAY SHRINK EVEN. Get to know more on Dew Articles.
Air purifiers are different from ordinary household appliances. You can get by with a small TV, and you can tell if the refrigerator is cool by touching it. But the use effect of air purifier needs to be objectively evaluated, either suitable for your home, or not suitable for your home. This requires us to sharpen our eyes when buying, and not be easily confused by the so-called brand awareness, marketing and promotional means.
