Because we spent a lot of time at car? Normal car do have air filter but only able to filter big particle like smoke or dust.
There are a lot of car air purifier in the market, you can have a look.
https://www.toptenthebest.com/automotive/to...-air-purifiers/

Next step is probably a spacesuit for earth.

Inside still mention that, some odor ingredients absorbed by the filters may become separated and may be discharged through the air outlet and result in additional odor. Depending on the usage environment, especially when the product is used in a condition significantly more severe than household use, this odor may become strong in a shorter period than expected.

The air purifier is designed to remove air-suspended dust and odor,  but not harmful gases (for example, carbon monoxide contained in cigarette smoke). 

If the odor sources still exist, it cannot completely remove the odor (for example, odors from construction materials and pet odors ). It is suggested to open the window a bit when you are smoking in order to facilitate ventilation. In this case we recommend purchasing the optional replacement filter.

Then what is the purpose still purchase this air purifier ah?

Means it can remove cigarrete smoke in room? If the ppl smoke inside room

What is the price and how long it need to change the filter? The maintenance cost how much?

Why home no need change the filter? It may lose it efficacy since the filter will dirty for so long time.

How long have you use for the home? How do we know when to change the filter?

Wonder its really can last 10 years? Hmmm....

I am not consider the maintenance cost actually. Is seeking is it the air purifier can work function well effectively since it filter only need change 10 years once. 

If the air purifier is lost maintenance cost but at last not really work it efficacy then macam lost the function already.

Most manufacturer will have more than 10 years part support, or you can buy a few to keep?

You are right also... But how if it's discontinued? Throw and buy another one?

Then how if the sharp AP filter discontinued after 10 years since 10 years so long time?

I have one unit of atmosphere inside my dad room coz his room really full of dust that we cannt see it as he cannot sleep well. Now so far so good the room does not contain any weird smell. So it is quite good for me. The main is when it turn on turbo speed there is no noisy sound as other, the turbo speed able to clear and clean the air in up to a 390-square-foot room in a short time and very save electric. 

Why don't get a better one with better parts support & service? It might be pricey but at long run you no need to headache to switching & throw away.

Good then, as long as it serve you what you intended for.
If you wanna get a new one, don't throw it, send it to me I pay for the delivery haha...

what is the difference between humidifier and dehumidifier? which one better use in a room?

and here I am thinking all sorts of cheap ways to dehumidify my apartment....
you growing mould or something? 

Every week I had a lot of dusts accumulated in my room even without any open windows facing the road/construction site etc, using vacuum cleaner to clean my room everytime but not sure whether an air purifier is needed or not.

for no.2 by blow inside does make the air doesn't move a lot  which less dust to carry? bit confusing 

I am looking for an air purifier as well, any recommendation on model with HEPA + Carbon filter?

I was searching for a ventilation fan solution to suck outside air in, with PM2.5 filter in the past but not avail.
Until today, I discovered Xiaomi is selling the exact product that I wanted.

Xiaomi Fresh Air Ventilator
https://www.mi.com/fresh-air-ventilator/

The outside air can be extracted through wall or window.
https://www.mi.com/fresh-air-ventilator/notes/