1. What are N95, P2, FFP2 and KN95
First of all, these are the standards of masks, not the brand of a certain mask, not the model of a certain mask, not the function of a certain mask, but the standard of a mask, is a standard, standard, standard!
1.1 Where are these standards
N95-American implementation standard, certified by NIOSH (National Institute for Occupational Safety and Health)
FFP2-European implementation standard, derived from the implementation standards of EU member states jointly developed by the European Organization for Standardization and other three organizations
P2-Australia and New Zealand implementation standards, derived from EU standards
KN95-China designated and implemented standards, commonly known as "national standard"
2. What are the specific criteria
Generally speaking, the above standards are the minimum filtration efficiency standards of masks under a certain test environment, that is, the filtering effect of these standard masks will not be lower than a fixed value
First of all, please see the explanation of Baidu Encyclopedia: N95 masks are one of the 9 types of particulate protection masks certified by NIOSH. "N" means not resistant to oil. "95" means that when exposed to a specified number of special test particles, the particle concentration in the mask is more than 95% lower than the particle concentration outside the mask. The 95% value is not the average value, but the minimum value. N95 is not a specific product name, as long as it meets the N95 standard, and products that pass the NIOSH review can be called "N95 masks." The protection grade of N95 means that under the test conditions specified by the NIOSH standard, the filtering efficiency of the mask filter material to non-oily particulate matter (such as dust, acid mist, paint mist, microorganisms, etc.) reaches 95% 
Then please see the explanation of FDA: N95 Respirators. An N95 respirator is a respiratory protective device designed to achieve a very close facial fit and very efficient filtration of airborne particles. The 'N95' designation means that when subjected to careful testing, the respirator blocks at least 95 percent of very small (0.3 micron) test particles. 
Summarize and briefly explain that N95 is: NIOSH certification, filtration efficiency 95%,
2.2 P2, FFP2, KN95
With the foreshadowing of N95, the rest is easy to understand
FFP2: EN standard, minimum filtration efficiency 94% 
EN (European Norms) is an EU standard, drafted and maintained by CEN, CENELEC and ETSI
P2: EN standard, minimum filtration efficiency 94%
Same origin as FFP2, but only implemented in Australia and New Zealand. Whoever has the word "M" on the flags of Australia and New Zealand?
KN95: Chinese national standard, GB2626-2006 Respiratory protective equipment self-priming filter anti-particulate respirator standard, minimum filtration efficiency 95%
Again, these are the standards for filtration efficiency and do not represent any function
2.3 Differences between these standards
The above standards are the percentage of the filtration efficiency of the mask, and there is no difference. It does n’t matter if you think that the minimum efficiency of 94% and the minimum efficiency of 95% are different.
(1) 3M said the company The US N95 standard is roughly equivalent to FFP2. 
(2) Use the N95 / P2 expression directly on the website of the Queensland Government of Australia 
(3) Australia 3M wrote this for medical 1860 masks
Why are 94% and 95% equal? Is imperialism deliberately enticing us to be fooled? Then destroy me? You guess
In this regard, a foreign website explains very well
Because 94% and 95% are the lowest filtration efficiency, the actual efficiency should be between 94-99 and 95-99 percent, respectively. And what is the specific number, no one is sure, except to send each one to the laboratory for testing. So in this bounded interval, we can think of FFP2 / P2 = N95
The original text is as follows
Are N95 / N100 better than FFP2 / FFP3?
Actually, no. It's important to note that these standards only specify the minimum% of particles that the respirator filters. For example, if a mask is FFP2 rated, it will filter at least 94% of particles that are 0.3 microns in diameter or larger . But in practice it will filter somewhere between 94% and 99%. The precise figure will often be quoted by the manufacturer in the product description. 
Similarly, the minimum filtration efficiency of 95% specified in China's national standard KN95 can also be equated with N95
Conclusion: N95, FFP2, P2, and KN95 are all equivalent and can effectively provide protection.
3. "Splash-proof" function
I saw "something" and "somehow know" that everyone said that FFP2 / P2 standard masks are "not splash proof". My little fingernail cover said to me: People who make this statement are stupid *
The English text of this term is "Fluid Resistant"-fluid-resistant / fluid-resistant (I don't know how to translate it). As we said before, N95 or FFP2 / P2 are all standards for mask filtration efficiency, not a certain function. Does the mask have the function of preventing splashing? Obviously, it is not a matter of NIOSH or CEN, nor is it a matter of China Quality Supervision, Inspection and Quarantine and the National Standards Committee. They only care about four words-filtration efficiency, so N95, FFP2 / P2 , KN95 has nothing to do with "splash proof".
So how did this rumor come about, then you have to mention a certain post
The gangster who did the rigorous homework (Dasha *) said that the N95 has a splash function, but the P2 does not. Fang Lingtang's humility. And, he (she) also produced evidence, the evidence is a N95 standard mask with Fluid Resistant function (3M 1870), and a P2 standard mask without Fluid Resistant function (3M brand unknown model), as shown below:
According to this "impeccable" logic, as long as I find a healthy Chinese and a disabled American, I can say that all Chinese are healthy and Americans are disabled ~~~
To be honest, let's say "splash-proof", the accurate English name should be Fluid Resistant, which is a specific function of a certain type of mask, not a necessary attribute of N95 masks.
Such as: 3M 8210, N95 standard, not "splash proof"
3M 1860, N95 standard, "splash proof"
It is also the N95 standard, why are the functions different-because the uses are different:
3M 1860, professional medical anti-particulate mask and surgical mask
3M 8210, professional dust mask
Can surgical doctor's masks be Fluid Resistant ("splash-proof")?
Masks for electric welders and lumberjacks to prevent "splashing" of a hammer
Summary: N95, FFP2 / P2, KN95 are filter efficiency indicators, not functions. The specific function depends on the specific model, and the required model depends on the purpose.
3.2 What is "splash proof"
First of all, what is the so-called "Fluid Resistant"? I'm not talking, please see the authority's statement
Australian medical device giant BSN said this: For all surgical procedures, or in any area where there is a risk of blood or body fluid splash. 
3M said this to a certain Fluid Resistant product: Comfortable earloop procedure mask easy to put on and remove Intended to help reduce exposure to blood and body fluids 
Simple translation + summary: surgical operations may have the risk of blood spray or other body fluids;
Some masks can reduce exposure to blood or other body fluids.
Open our little fingernails and think about what this Fluid Resistant is preventing-blood, urine, no matter what fluid, he is fluid. Why do experts recommend N95 to us instead of liquid-resistant N95, because ordinary people can hardly encounter virus-containing liquid splashes in ordinary scenes.
Let's continue to see what the big brother who has done rigorous homework said: "How important is" splash proof "? He used sneezing as an example.
Sneezing is indeed a way of spreading a terrorist virus, but what is the connection between sneezing and Fluid Resistant? My little nail cover was rotten and I didn't think of it. Is liquid sneezing? Sneezing broke the great artery? Or the urinary system has a long face?
Shouldn't the sneeze squirt "droplets"? ? Academician Zhongnanshan emphasized countless words-droplets infected by droplets! Droplets! Droplets! The Fluid Resistant protects against large amounts of blood or other liquids. I do n’t think that droplets can be considered liquid ...
Finally, let's take a look at the new word created by the great god out of thin air. What is the so-called "splash proof"?
3M did not mention "splash-proof" for professional medical 1860 masks, but said that it has the ability to block liquids; so Fluid Resistant should not be called "splash-proof", but should be called liquid barrier.
This liquid barrier function why ordinary N95 masks are not only available in special models, because we ordinary people do not need.
4. Write at the end
N95, FFP2, P2, KN95 have equivalent filtration efficiency, as long as you can buy any of them, you can effectively protect you and your family.
Academician Zhong Nanshan said on CCTV: "I heard that N95 is out of stock. In fact, it is not necessary to wear N95 ... General masks such as surgical masks can also block most viruses that are stuck in droplets. Wearing a mask is useful. . "Therefore, even if the above-mentioned high-standard masks are not available, ordinary masks can block some of the viruses in the droplets.
Unfortunately, whether you admit it or not, we are all leeks and will inevitably be cut. In this case, don't take the initiative to pay IQ tax even worse.
Question how valuable the spirit is, but many people do not.
The brain is also a good thing, but unfortunately many people do not.
In the end, I do n’t wish you all a suitable mask to protect yourself.
I wish you all your brains back, because after you have your brains, you can do more than just buy a suitable mask.