I'm way out of my domain of expertise here, not being automotively or mechanically inclined at all, so would like some brief orientation here. I'm not seeking any particular brand, only something that will work at a verified/rated quality standard.
So briefly as a back story, I'm getting sick of my Nissan Frontier (2014) allowing a certain amount of exhaust from other vehicles through the cabin air filter even after a brand new one has been installed (by Nissan themselves), and I hit a dead end with customer support who told me they have no higher grade filters than was already in it, so decided to do "freelance" research.
The Question: How can I find a grade of filter which filters out at least 95% (or better 98/99%) of pollutants or more? I don't mind paying a premium for superior quality and protection of a fine grain filter.
Though the announcement seems gimmicky because of the Coronavirus pandemic, it has been in the news lately that a Chinese vehicle manufacturer has achieved a N95 equivalent air filtration rating. As Business Insider reports: "The Icon's air filtration system is N95 certified, which means it blocks at least 95% of small particles that measure 0.3 microns." That description interests me. All I care about for purposes of this question are pollutants, not viruses, passing through the filtration system though.
I really don't want cough-inducing levels of exhaust and strong odors from the vehicle in front of me to enter the cabin when my vehicle it is pulling external air (vs. recycling internal air). Not to mention pulling external air is the default in my vehicle. Obviously nothing will achieve 100% filtration, but surely some filter can do better than what I'm experiencing.
Now, I had never heard of AZUMI (my examples are random, not preferential) or their products until today, but their blurb on their filters (though I have no idea if it reflects their quality) hits the central concern:
Air in the midst of traffic contains five times more exhaust gases, pollutants and allergens than the air you experience standing by the roadside. On top of that, airflow through a vehicle’s air ducts can go as high as 540,000litres/hour. The only barrier between healthy lungs and the cloud of pollutants during every drive is the cabin air filter that you decide to install.
A clean air filter aids in trapping pollen, allergens, smoke, fumes, and odors...
One company that looked like it actually had air filters that claimed a certain filtration percentage was Valeo, which is (for me) an international company that I'm unsure whether I can have their products shipped overseas to receive them. But even with Valeo I didn't know how to verify that a product was actually formally rated for a certain filtration percentage. A different manufacturer - by contrast - of what looked like a popular brand of air filter, to take one random example, was TYC. But they didn't list any formal filtration specs either on the product page. So where do I look to find that information?
Maybe there are more detailed 'data sheets' I'm missing on a given manufacturer's website, but if such things are available that's the kind of information I am seeking and would like to be made aware of.
How can I be assured when researching for a high grade, high filtration cabin air filter that I am getting a product that is actually rated at a certain level, to where I could actually compare it to other products to determine whether its quality is superior? Can someone give me some more objective and precise criteria and tools to use to locate high grade filters for automobiles?
I haven't the faintest idea where to start beyond my sporadic internet searches.