What environmental factors contributed to the spanish flu and its spread?

I think this might help.

Avian influenza (bird flu) has the potential to cause a healthcare crisis of unprecedented global dimensions. Many predict a global pandemic far worse than the 1918 Spanish Flu, which killed 40 million to 50 million people. A larger, denser global population, coupled with modern transportation systems of both goods and people, could result in a pandemic killing far more people worldwide. The consequences of such a pandemic would stretch beyond just public health. International relations, commerce, politics, travel, medicine, and economic and social infrastructures would be affected due to widespread infection and worldwide mitigation efforts. 

Remember soh-cah-toasoh: cah: toa: now, looking at the picture we can see that we have an angle, the hypotenuse and want to find the value of the adjacent side to the angle. so we use cah to find the adjacent angle. plug in what we have: we need to solve for x now so we get it by itself on one side: plug this into your calculator and you'll find that: