Chemical and carbon air purifier are types of purifiers which employ carbon and/or chemicals to filter gas, smoke and odor. As you might know, one of the biggest reason why someone wants to buy an air cleaner is to get rid of smoke, bad odor, and harmful gases.
Carbon Air Filter – How Does It Work ?
So how does a carbon air filter work ?
Carbon air purifier works by trapping or absorbing gas molecules down to 0.001 micron or smaller, into its tiny pores. So you see, in order for a carbon air filter to do its job, it needs to have tiny pores to trap gases.
But how come a carbon has tiny pores ? Carbon can be made to have tiny pores by heating and steaming it. Carbon with tiny pores is said to be activated.
Once these tiny pores are saturated with gas, the carbon filter won’t be able to absorb anymore contaminant. At that point, you would need to replace it.
To prolong the life of a carbon air filter, it is important to have a good pre-filter so that the pre-filter can filter out the higher molecular-weight particles, leaving only gases for the carbon to absorb. That’s why you never find a gas air purifier with only a carbon air filter in it. A carbon air filter is always be an add on to either a HEPA air purifier or an electrostatic air purifier. Therefore, if you want to buy a carbon air purifier to control gases, then you would have to buy a HEPA air purifier which has either chemical or carbon air filter added to it.
What Does a Carbon Air Purifier Remove ?
Carbon air filter removes any gases which are in the range of 0.001 microns or smaller. These gases are usually volatile or semi-volatile organic compounds. Smoke and pet odor are included here.
However, carbon air purifier is not effective in removing gases if installed in humid conditions where the air has lots of water molecules in it. If you live in such condition, you would need a chemical air purifier to address the gas problem just because carbon would not be effective here.
Equally, carbon air purifier also does not filter the smaller molecular weight gases including all inorganic gases like ammonia and a minority of organic gases such as formaldehyde. If you need a gas air filter for filtering the gases I mention above, then you need to buy an air purifier designed specially to get rid of gasses which also has chemical absorbent.
So how does a chemical air purifier work ?
Chemical air purifier works by removing gases through chemical reactions. Basically, the chemicals – also known as Chemisorbers – reacts with the water molecules in the air and also with gas molecules to break them chemically into harmless forms such as carbon-dioxide. This way, unwanted gases are removed. A chemical air purifier usually uses chemisorbers which may include alumina oxide, alumina silicate, and potassium permanganate.
Gas Air Purifier Buying Guide
There are several things you should know prior to buying a gas air purifier
First, you need to know what kind of gas you want to remove. If you want to get rid of volatile or semi-volatile organic compounds such as smoke and pet odor, then you can buy an air purifier containing a carbon air filter. However, if you want to remove small molecular weight gases such as inorganic gases and formaldehyde, you should buy an air purifier with chemical absorbent in it
Second, look out where you live or where you would like to use the gas air purifier. A carbon air purifier would not work well in a humid place. So, if you want to get rid of gases in this place, then you should get a chemical air purifier instead.
Third, when shopping for a gas air purifier, look for the one with decent pre-filtering capability. You want all the big particulates to fall into pre-filters first, leaving only the carbon or chemical absorbent to deal with gas. If the pre-filtering stage does not work well, then the carbon or chemical air filter will have to deal with the big particulates as well, hence saturating it prematurely. Therefore, ideally, a gas purifier should have a pre-filter which can trap big particulates and a HEPA filter which filters particulates up to 0.3 micron. This way, the carbon or chemical air filter only deal with gases.
Fourth, look into the design and amount of carbon or chemical absorbent contained inside a gas air purifier. In order for a carbon or chemical air purifier to work effectively, it needs to have at least 15 pounds of absorbent. Most discount gas air purifiers do not have such amount of absorbent. Instead, they only have ounces of it, which is not enough to make a difference. In addition, the design of the absorbent can play a role in determining the effectiveness of a gas air filter. You would want to have a carbon air purifier which has carbon air filter in pleated design. This design enables the filter to have larger surface area. This makes the filter capable of passing and filtering large amounts of air.