I was just in Santa Ana and Anaheim California which has lots of large families that are living in sub-standard and outdated housing.
I have noticed at grocery stores and department stores that many children are coughing from the crowded, filthy living conditions from living in petite homes with large families.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1257572/
Alot of these children also get to go to schools with 40, 45 and 50 students per class in crowded neighborhoods according to this article.
http://laschoolreport.com/commentary...-overcrowding/
I guess there has been research but when ever I back in Gilbert, I know that with the McMansions that many grow up, I rarely hear hacking children in public.
Then again in Gilbert the typical family lives in a large, spacious 3,000 square foot home on a nice, big lot.
In Santa Ana and many poor, old towns like San Bernadino the homes are tiny and the children and families crowd into tiny homes.