The correct answer to this open question is the following.
Although you did not provide any context, excerpt, text, link to an article or video, we can answer in general terms.
It seems that your question refers to a documentary where specialists talk about the problems and risks of overpopulated Asian_American neighborhoods in Northern California and Seattle, Washinton. If that is the case, then we can comment on the following.
What affluent neighborhoods take for granted that promotes better health that is often lacking in disadvantaged neighborhoods is the fact that the people who live in affluent villages or neighborhoods have the advantage of having better infrastructure and environmental help to maintain good health conditions. This means a better trash collection system, better medical infrastructure such as hospitals, emergence service, more governmental supervision on the streets, and more.
Less favored neighborhoods lack infrastructure or policies that affect people's lives. In these neighborhoods, people live in overcrowded spaces with no ventilation and disease could spread more easily among the inhabitants.