Environmental Justice in Baltimore, MD: Insight from BC Measurements from a Mobile Laboratory

The City of Baltimore, MD has a history of problems with environmental justice (EJ), air pollution, and the urban heat island (UHI) effect. The fine spatial scale of atmospheric EJ events makes them difficult to detect with remote sensing (satellite) techniques or surface-based monitors as federally-mandated; chemical transport models lack the resolution to simulate concentrations on the scale needed – about 100 m. In this paper we introduce the capabilities of a mobile laboratory, the Air Resources Car, or NOAA’s ARC and present initial results revealing frequent incidences of black carbon (BC) air pollution at concentrations associated with adverse effects on respiration and cognition in children. Several areas of locally high concentrations were documented near major highways, downtown, and in the Curtis Bay neighborhood of Baltimore. In a case study of Curtis Bay, higher concentrations of BC aerosol were measured along Pennington Ave., (mean [5^th to 95^th percentiles] = 2.08 [0.2 – 10.9] mg m^–3), than along Curtis Ave. just ~150 m distant (0.67 [0.1 – 1.8] mg m^–3). Other species, including Criteria Pollutants O₃, CO, NO₂, and PM2.5, showed little gradient. The difference in BC appears to result not from heavier truck traffic or slower dispersion but from the interruptions in traffic flow. Pennington Ave. has three stop lights while Curtis Ave. has none. As heavy-duty diesel-powered vehicles accelerate, they experience turbo-lag and the resulting rich air-fuel mixture exacerbates BC emissions. Mediation might include diverting heavy-duty trucks away from residential areas, replacement with electric vehicles, or smoother traffic flow.