Local and regional influences on VOC sources in the New York city metropolitan area

Because of its proximity to jurisdictional boundaries, understanding the spatial origins of volatile organic compounds (VOC) is critical for effective air-quality management in the New York City (NYC) metropolitan area. The combination of dispersion-normalized Positive Matrix Factorization, the Lenschow approach, and Concentration-Weighted Trajectory (CWT) analysis disentangled local versus regional contributions across six sites. Several factors exhibit predominantly regional influences. CWT fields reveal broadly consistent southwest–west transport pathways across source types, highlighting the role of synoptic airflow in shaping VOC variability. A high-quantile analysis shows spatial contraction toward the New Jersey corridor during peak events, indicating dominance of nearby regional and local sources under stagnation-prone conditions. Limitations of background-based apportionment were observed when key tracers are absent from the lower concentration background site. Overall, combining receptor- and trajectory-based approaches elucidates the scale of source influence and supports a two-tier control strategy: local actions targeting traffic and fuel handling, coupled with coordinated regional measures aimed at secondary/aged contributions, informing ozone control in nonattainment areas.