Nothing "pulled from air" in ammonia production is expensive. The energy intensive part is making hydrogen, and then pressurizing the nitrogen and hydrogen.
Currently, hydrogen is produced from natural gas, but renewable hydrogen from electrolysis would be fine. And at the rate the cost of solar is declining renewable hydrogen is going to be competitive soon (nuclear hydrogen, not so much.) And if renewables are over-installed to deal with intermittency there will be a lot of excess power intermittently available. The key technology here would be mediocre efficiency, but low capital cost, membraneless electrolyzers.
And the big one, artificial fertilizer, which uses natural gas because the electrical equivalent to pull what we need from the air is astronomical.