Fine-grained inequity: Linking urban metabolism to indoor air quality

A longstanding challenge for the industrial ecology community has been to link studies of material flows and metabolic processes to endpoints that matter to people. Public outrage and policymaking tend to flow from visible... [ view full abstract ]

A longstanding challenge for the industrial ecology community has been to link studies of material flows and metabolic processes to endpoints that matter to people. Public outrage and policymaking tend to flow from visible impacts of environmental stressors. Tracing the long causal chains linking activities like fossil fuel production to changes in, say, human morbidity is difficult, and many researchers are content to tell only part of the story and leave the rest to others. However, efforts to trace out more of the causal chain can bring new insights, especially regarding the distributional consequences of urban metabolic processes.

People spend 90% of the average day indoors, so that indoor exposures of airborne pollutants are the key to understanding many health effects. This paper shows that humanity’s perturbations of the global carbon cycle, once adequately contextualized, contribute to changes in indoor air quality and associated health outcomes that vary widely among people living literally next door to one another. We have linked and calibrated a series of system models, each at a different spatial scale, to characterize this long causal chain and the interactions among its links. Models include a global circulation model that projects future climatic conditions, a regional downscaling model to specify local values of key climate parameters, a regional electric power system model that simulates air pollution emissions associated with temperature-sensitive changes in electricity demand and power plant performance, a local air pollution model that calculates air pollutant concentrations due to local emissions sources and air circulation patterns, a building information modeling suite that simulates energy consumption and indoor air quality, and an occupant behavior model that interacts with building systems and accounts for individual health outcomes.

The region studied is the New York metropolitan area, specifically the occupants within apartments owned by the Housing Authority of the City of Elizabeth, New Jersey. These buildings are surrounded by the New Jersey Turnpike, Newark International Airport, the Port of Newark and New York, and the Bayshore petrochemical complex, and the city has New Jersey’s worst air pollution. Only some apartments have air conditioning. Health outcomes including heat exhaustion and asthma attacks seem most prevalent among socially isolated seniors living without central air conditioning during summer heat waves in this city.    

This calibrated multi-level modeling system reveals that at every scale people can make choices and influence outcomes. It conveys a refreshing sense of agency. Globally, we can deploy cleaner energy sources and change land use patterns. Regionally, we can redesign key infrastructures and settlement patterns. In buildings, we can install air conditioning systems and tighter envelopes. Individual occupants can adjust thermostats, windows, and clothing, or move to a different location. The equity aspects of the story that are invisible at the global level become highly visible once we have the ability to look at individual occupants and housing units. It is this ability to reveal both agency and outcomes that allows us to characterize inequities in a fine-grained urban metabolism. This work is funded by NSF grant AGS-1645786.