The bruised and bloodied face of a 4-month-old  girl attacked by a raccoon in her home is gruesome, but Journi Black's plight might do far more to bring home the complexities of affordable housing than any building blueprint or policy discussion can.

Last week, the baby's mother moved her and a sibling into a rooming house that was in such a bad state of repair that a raccoon entered  through a hole in the wall and attacked the baby.  The mother was paying $375 a month for two rooms in a house that was not zoned for that kind of dwelling.  No surprise there: For too many, "Philadelphia" is Greek for "zoning violations."

That situation is a microcosm of the city's affordable housing woes,  one that will not be solved by installing a few units inside market-rate high rises — as is the hope of many housing advocates and Councilwoman Maria Quiñones-Sánchez, who proposed a bill requiring affordable units in market-rate housing construction.   Rather, we have to recognize the reality of this city's housing stock, which is defined by a high rate of home ownership coupled with a high poverty rate. That means that homeowners, including landlords, can't afford to keep their houses in repair.

For the last few years, we've known that vacant properties in the city number about 40,000 and that numerous programs, including a Land Bank, have been created to deal with them.  What we still don't know is how many houses are currently occupied, by owners or renters, but are in dangerous disrepair.

The city has made attempts to deal with the situation.  A trust fund was established in 2005 to provide money for affordable housing as well as repairs;  a Basic Systems Repair program provides help, but demand exceeds supply.

The lack of affordable housing isn't a real estate problem. It's a health problem.   A study by the city's Public Health Department in 2015 drew bold lines between housing and many health problems facing the city's children as well as adults:  lead poisoning, asthma, injuries, emotional and behavioral problems.

The privately funded Healthy Rowhouse project is another initiative that recognizes the real risks of houses in disrepair.  It was created by the Design Advocacy group, and now is run by the nonprofit financial service Clarifi, to help generate better policies that connect health and housing.    It argues that a small loan or grant for repair is far more inexpensive, and efficient, than the human and financial costs of abandoned houses: more vacant properties, and families and children traumatized by constant moves or homelessness.

Recent City Council hearings and Sanchez's bill have moved affordable housing to the center of a public debate, one focused on whether market-rate developers should be forced to include a  minimum number of affordable units in their projects; in exchange, they would get to build higher buildings. Or, they could contribute to a housing trust fund.  That bill was put on hold last month,  a sign of the complexities of housing problems in the city.

Now, the image of a mauled baby may serve to remind us of a simple fact:   If it isn't safe, it isn't affordable.