There are many air purifiers available today that work purely on the basis of negative ion generation. Many air purifiers that have mechanical filtration too have an on-board negative ion generation too. So how do these negative ion generators work, are they effective and are they safe? These are some of the questions that we will be tackling today.
What is a Negative Ion and what does it do?
When air passes through a negative ion generator or an ioniser, it is infused with an electrical charge. This charge causes some molecules present in the air to become charged. Usually, this is Oxygen or Nitrogen molecules which become charged positively or negatively. As these molecules become charged, they are quickly surrounded by Oxygen molecules which cluster around them.
This is the first thing to note about Negative ion generators. The fact is that negative ion generators produce both positively and negatively charged ions. Most negative ion generators claim to produce negative ions exclusively. This is impossible to do as ions are always produced in pairs.
Now lets talk about what these ions actually do in terms of air purification. When ions are created by the negative ion generator device, pollutant particles and aerosols present in the air get attracted to these ions and attach themselves to the ionised molecule. This happens via a process known as electrostatic attraction. Due to this electrostatic attraction, multiple pollutant particles and aerosols start colliding among each other and thus start becoming bigger in size.
How does a Negative ion generator reduce pollutants
As we saw previously, negative ion generators produce charged particles called ions. These ions attract various pollutant particles and aerosols to them through electrostatic attraction. Thus you have clusters or large pollutant particles created within the air. This air is then released back into your room.
Now since most of the pollutants have clustered together to form larger particles, they are now much bigger and heavier. As a result, when they are released back into the room, they fall down on the floor much more quickly than before. Alternatively, these pollutant particles can also deposit themselves on the nearest wall or surface through the process of electrostatic attraction.
The end result is that these pollutant particles are removed from the air in your room and deposited in larger clumps either on the floor or on the walls and other surfaces.
What a negative ion generator does not do is trap the pollutants within the air purifier itself. This has the advantage of making sure that the negative ion generator device does not require any maintenance. The disadvantage of course is that the pollutants are not captured and are still in your room in one form or the other.
Health Benefits of Negative Ion Generators – are they Real?
It has been claimed for a long time that negative ions have health benefits when they are inhaled. You might have read claims that the air near waterfalls is rich in negative ions and that air which has more positive ions feels stuffy. These claims are frequently made by people in the wellness industry and not by actual doctors or scientists. The fact remains that there has been no proof yet that having a higher concentration of negative ions produces any sort of health benefit at all.
In fact, some common examples can show that these hypotheses are completely baseless. Air at a higher altitude on a mountain usually feels fresh and clean. However, this air has a much higher concentration of positive ions as compared to negative ions. In contrast, the air before a thuderstorm strikes frequently feels heavy and stuffy. This air in fact has a high concentration of negative ions.
This is the second myth about negative ion generators. The belief that having negative ions in the air that you breathe is completely baseless and has never been proven through any sort of scientific study.
Negative Ion Generators and Ozone
A side effect of negative ion generators is that they produce a small amount of Ozone during their operation. While Ozone is a very helpful gas in the upper reaches of the atmosphers, on the ground level it is considered a pollutant. When breathed in, Ozone can cause chest pain, coughing and irritation.
The amount of Ozone produced by most negative ion generators is a few milligrams every hour. This is well within the safety limits prescribed by the California Air Resources Board (CARB) which was one of the first regulatory bodies to introduce a rule for the Ozone levels released by negative ion generators.
However, when negative ion generators are used in ill-ventilated rooms over time, the concentration of Ozone in the room can rise gradually until it reaches unsafe levels. As per safety standards instituted by the National Institute for Occupational Safety and Health (NIOSH), Ozone concentration must be below 100 parts per billion (ppb).
A scientific study that aimed to look at Ozone concentrations produced by negative ion generators found that even devices with low Ozone production can raise the Ozone levels in a room beyond 100 parts per billion if used continuously in rooms with poor ventilation.
Negative Ion Generator – Sharper Image and Consumer Reports
Another interesting anecdote related to negative ion generators is the lawsuit between The Sharper Image and Consumer Reports. In 2003, Consumer Reports said that air ionisers and negative ion generators do not perform to the same standard as HEPA filters when it came to air purification. The Sharper Image, which made air ionisers, sued Consumer Reports for this saying that their testing methodolgy was incorrect.
The case was dismissed eventually since The Sharper Image was not able to prove that any of the statements made by Consumer Reports was false. The Sharper Image had to pay up about half a million dollars to cover Consumer Reports’ legal fees.
Negative Ion Generators – Conclusion
Negative Ion generators are frequently touted as being great for air purification along with providing other health benefits. The first myth about negative ion generators is that they capture air pollutants. Most negative ion generators will reduce the level of air pollutants in your room by getting them on the ground or on the nearest surface faster. They do not capture these pollutants at all.
The second myth is that negative ion generators provide a health benefit since negative ions are frequently found in nature in places where the air is fresh and clean. The fact is that no health benefit of negative ions has even been proven and negative ions are found in plenty of places where the air is not fresh and clean too.
Finally, negative ion generators also release small amounts of Ozone. Over time, the level of Ozone in the room where a negative ion generator is running can rise to unsafe levels, especially if the room is poorly ventilated.
Overall, you would be far better off by choosing an air purifier that has HEPA filters. These devices are proven to reduce the concentration of pollutants in your room and have no major side effects.
Negative Ion Generators – Frequently Asked Questions
In case you prefer the Q&A method, here is all the information about negative ion generators summarized in a few questions.
Do Negative Ion Generators remove solid particulate pollutants?
Negative Ion generators do have a beneficial effect when it comes to the removal of particulate pollutants. As air passes through negative ion generators, particulate pollutants collide among each other and turn into large and heavier particles. These particles either fall on the ground or are collected on surfaces like walls after being released from the air purifier. So negative ion generators remove particulate pollutants by taking them out of circulation from your room’s air.
Do Negative Ion Generators have any health benefits?
While there are many claims that state that negative ion generators have health benefits, these have not been proven in any way whatsoever. You might read that negative ions are found near waterfalls and in nature, these claims too do not mean that negative ions have any health benefits at all.
Are Negative Ion Generators better than HEPA Filters?
Negative ion generators are definitely not as good as HEPA filters for air purification. HEPA filters will remove at least 99.97% of particles that are 0.3 micrometers in size. This will ensure that a large proportion of pollutants like PM2.5 particles are removed. Negative ion generators do not have this benefit and their air purification cannot usually be quantified.
Are there any side effects of using Negative Ion Generators?
Negative ion generators have the side effect of producing Ozone in small amounts. While the amount of Ozone produced by negative ion generators is usually well within all safety limits, Ozone can accumulate, especially in poorly ventilated rooms. Ozone is a known pollutant and lung irritant and inhaling it can cause multiple symptoms.
Is the amount of Ozone produced by Negative Ion Generators dangerous?
Most negative ion generators produce a few milligrams of Ozone for every hour of operation. A scientific study found that the Ozone levels in a poorly ventilated room that has a negative ion generator can quickly rise above accepted limits. The bottom line is to not use Negative ion generators for extended periods of time in poorly ventilated rooms.
