Thurston, Pope and others cautioned against reading too much into the monitor's data.
"[Pollutant] concentrations get diluted pretty fast as you get away from the sources," Rutgers environmental science professor Barbara Turpin says, arguing that the high PM2.5 levels measured by the Jersey City and Newark monitors, sitting so far from the George Washington Bridge, do not necessarily show the pollution levels being generated by the traffic jam.
Still, Carlton says, the only apparent change in the area from Sept. 9 to 12 was the traffic jam.
"If we think about what emits particles – Burger King, other industries like that – there was no new Burger King that started operating and caused that to happen," she says. "But we know that particles can come from cars, and that's the only thing that happened that was different."
Looking at the higher PM2.5 level each day, she continues, "If you think that there were a whole bunch of cars waiting – cars that would normally have a 45-minute commute, but idled for three hours – those emissions have to go somewhere, and it seems to me that that's where it's from."