You are here:
Back-trajectory modeling of high time-resolution air measurement data to separate nearby sources
Citation:
Hagler, G., D. Birkett, R. Henry, AND E. Thoma. Back-trajectory modeling of high time-resolution air measurement data to separate nearby sources. 2017 CMAS Conference, Chapel Hill, NC, October 23 - 25, 2017.
Impact/Purpose:
This presentation describes the results of the Region 2 Port-area Investigation of Emissions Reduction (R2PIER), which is a Region 2 RARE project that led to a three-year monitoring study near the Port of Newark.
Description:
Strategies to isolate air pollution contributions from sources is of interest as voluntary or regulatory measures are undertaken to reduce air pollution. When different sources are located in close proximity to one another and have similar emissions, separating source emissions trends in situ is difficult. During 2012-2015, the EPA conducted the Region 2 Port-area Investigation of Emissions Reduction (R2PIER) project which collected 1-minute air quality and meteorological data at a site just south of the Port of Newark, New Jersey. This monitoring site was situated to maximize the ability to separate clustered sources, including the Port, the Newark International Airport, the New Jersey Turnpike, and other surrounding sources. Over three years, approximately 1.7 million measurements were made for PM2.5, sulfur dioxide (SO2), oxides of nitrogen (NO2, NO), carbon monoxide (CO), black carbon (BC), and local meteorology. New analytical approaches were developed to separate slowly varying from fast varying components of the time series, isolating the apparent component of the pollution time series attributable to local direct emissions. This separation indicated a significant component of the time series had a slowly varying characteristic, contributing a significant fraction of sulfur dioxide (43%), nitrogen oxides (56%), carbon monoxide (76%), particulate black carbon (59%), and particulate matter less than 2.5 micrometers in aerodynamic diameter (PM2.5, 73%). The direct emissions impacts isolated from the time series were input, along with meteorology, into the Nonparametric Trajectory Analysis (NTA) model. The model results indicate that the highest or second highest average concentrations of these pollutants were associated with air that came from the Port of Newark. These Port-attributed concentrations decreased by up to ~50% during the study. The notable exception was PM2.5 which increased during the study period.
