Abstract
Almaraz et al. reported that agricultural soils are a dominant source of NO (x) pollution in California (20 to 32% of total statewide NO (x) emissions). However, this conclusion may be undermined by the lack of agreement between their modeled estimates and previously reported empirical measurements, the extrapolation of NO (x) fluxes during hot moments to derive annual estimates, and the overestimation of nitrogen fertilizer consumption in California.