According to how the other half lives, what was the problem with only having the stairs and the hallway door for fresh air in buildings in the slums?

The air was stale and hot

Explanation:

At that time, there were no regulations about how the Factories should handle their waste/pollutants. So most of them just dumped them to the environment near the factory.

As a result, those who lives in slums near the factories have to experience u stale and hot air that is caused by the production. This caused many of them to develop some sort of respiratory illness.

united states government;

1. artillery

2. jose san martin

3.their economies remained dependent on outside powers.

4. drafted new economies

5. democracies have replaced dictatorships