Most probably the noise is piston slap, this noise is heard when the engine is cold and disappears when the engine is hot. if the slap is very strong when the engine is cold and the noise becomes less when hot but still the noise can be heard.
Sounds like a fan belt. Have it checked. or an sai motor
The fuel injectors make the ticking noise you hear at startup, especially when the engine is cold (colder temperatures).
changes in temperature and weather can cause noise was it cold when noise started and warmer when it stopped??
One cause of a popping noise from the front end while backing up in cold weather is the drive shaft. A mechanic can help find the problem.
Your IAC (Idle Air Control) valve is going bad. It is attached on your throttle body..
Usually air in the lines or possibly worn washers in the faucets.
something hitting the pipe, hot water pipe touching cold water pipe, or is it burping noise ? a tapping noise is sharp, do you live in an apartment ? is this a house, lot s of causes,
The noise shows that your attic is not well insulated. You need to get extra covering so the wind can not whistle through the gaps and make noises.
If its only when the engine is cold its the secondary air injection pump. It pushes air directly in the exhaust manifold to lower emissions. It should shut off after 30 seconds or so
It really depends on the cause of the noise. Every Inline-4 Cylinder car I have ever seen makes some kind of clicking type noise when they are started cold, I'm pretty sure it's noise from the mechanical valve lifters. If it's really concerning to you, take the car to a qualified mechanic.
I think it needs a nose job, a.k.a., rhinoplasty.