Long-Term Trends of Fine Particulate Matter in the Dallas–Fort Worth Metropolitan Area
Spatial and temporal trends in air concentrations of particles <2.5 µm in diameter (PM2.5) were compiled, portrayed, and evaluated for three monitoring stations in North Central Texas over a 22-year period. Two stations occupy the urban core of the Dallas–Fort Worth metropolitan area, and a third station lies at the northern edge of this area. Time series portrayed monthly averages of 1-hr PM2.5 concentrations for the entire period, as well as 1-hr PM2.5 concentrations for each hour in July 2021. Monthly time series showed a tendency for higher concentrations in summer months. Periodic upward spikes coincided with incursions of polluted outside air, especially Saharan dust.
Overall, concentrations trended slightly downward over 22 years, despite a large population increase over that period. Hourly time series showed higher PM2.5 concentrations at midday, attributed to more anthropogenic activity, as well as periodic upward cycles lasting approximately three days, attributed to external dust events. Strong associations were measured between stations, especially for monthly averages, but also for continuous hourly measurements. Results suggest the importance of internal and external sources, regional transport and mixing, and a need for subhourly monitoring to better define polluted air space for exposure assessment.
Speaker / Author:
Paul F. Hudak, PhD, Department of Geography and the Environment, University of North Texas