Temiz hava sayesinde insanlar daha sağlıklı yaşayabilir.

sayesinde means thanks to, by means of, or because of in a generally positive or beneficial sense.

So in this sentence, temiz hava sayesinde means thanks to clean air.

A useful contrast:

• sayesinde → usually positive or neutral result
• yüzünden → often negative, like because of in a bad sense

Examples:

• Temiz hava sayesinde → thanks to clean air
• Yağmur yüzünden → because of the rain

With nouns, Turkish usually puts the noun phrase directly before sayesinde without extra case marking:

• temiz hava sayesinde
• teknoloji sayesinde
• doktor sayesinde

So you can treat X sayesinde as a fixed pattern.

With pronouns, though, Turkish uses different forms:

• benim sayemde → thanks to me
• senin sayende → thanks to you
• onun sayesinde → thanks to him/her/it

So for learners, the easiest rule is:

• noun + sayesinde
• pronoun + special possessed form

Turkish does not have a direct equivalent of English articles like the and a/an.

So temiz hava can mean:

• clean air
• the clean air
• sometimes some clean air

The exact meaning depends on context. In this sentence, it is general: clean air as a concept.

That is very normal in Turkish. Bare nouns are common.

insanlar means people, so it sounds natural when talking about human beings in general as a group.

You could also say:

• İnsan temiz hava sayesinde daha sağlıklı yaşayabilir.

That would mean something like:

• A person can live more healthily thanks to clean air
• One can live more healthily thanks to clean air

So both are possible, but they feel slightly different:

• insanlar → people in general, as a group
• insan → a person / one / the human being in a generic sense

In Turkish, when the subject is already clearly plural, the verb often stays in the singular third-person form.

So this is normal:

• İnsanlar daha sağlıklı yaşayabilir.

And this is also possible:

• İnsanlar daha sağlıklı yaşayabilirler.

Both are grammatical.

The version without -ler on the verb is very common and natural, especially in general statements. Turkish does not always repeat plural marking on both the subject and the verb the way English does.

daha sağlıklı means healthier or more healthily, depending on context.

Turkish usually makes the comparative with:

• daha + adjective/adverb

So:

• sağlıklı → healthy / healthily
• daha sağlıklı → healthier / more healthily

Unlike English, Turkish does not usually add something like -er to the adjective. It simply uses daha.

More examples:

• büyük → big

• daha büyük → bigger

• hızlı → fast
• daha hızlı → faster

Formally, sağlıklı is an adjective meaning healthy. But in Turkish, adjective forms are often also used where English would use an adverb.

So:

• sağlıklı yaşamak means to live healthily or to live a healthy life
• daha sağlıklı yaşamak means to live more healthily

English often needs -ly, but Turkish usually does not. The plain adjective form can do the job.

So in this sentence, sağlıklı is best understood as describing the manner or quality of living.

yaşayabilir can be broken down like this:

• yaşa- → live
• -y- → buffer consonant
• -abil- → can / be able to
• -ir → aorist/general present ending

So the whole form means something like:

• can live
• may live
• is able to live

This is a very common Turkish pattern:

• gel-e-bilir → can come
• yap-a-bilir → can do
• gör-e-bilir → can see

In your sentence, it expresses general possibility, not a specific event happening right now.

Each form gives a different meaning:

• yaşıyor → is living / lives right now
• yaşar → lives / will live / tends to live
• yaşayabilir → can live / may live / is able to live

In this sentence, the idea is not that people are already living that way at this moment. It is saying that clean air makes healthier living possible.

So yaşayabilir is the best choice for general possibility.

Yes. Turkish word order is flexible, although the verb usually stays at the end.

The original sentence:

• Temiz hava sayesinde insanlar daha sağlıklı yaşayabilir.

A very natural alternative:

• İnsanlar temiz hava sayesinde daha sağlıklı yaşayabilir.

Both mean basically the same thing, but the focus shifts slightly.

• Starting with Temiz hava sayesinde highlights the cause first.
• Starting with İnsanlar highlights the people first.

So the original sentence is perfectly natural, and the fronted phrase gives a nice because of this emphasis.