1, nitrogen is a common gas, and nitrogen is abundant in the atmosphere, accounting for 78% of the air, which is sufficient, low in acquisition cost and cheap in price. The nitrogen content is less, accounting for five ten thousandths of air, and the extraction cost is high and the price is high.

2. Nitrogen and gas molecules are not easy to escape from balloons. Helium molecules are small and easy to escape from balloons. Therefore, nitrogen can make the balloon expand for a longer time. So nitrogen is good.