I live in a suburban area in Michigan. I, like most of my neighbors, use a gas fired furnace for heat and have a gas powered water heater. My NOx readings on my outdoor monitor show sporadic spikes, usually overnight, but they are inconsistent. My guess is that during low-wind periods the fumes from my high efficiency gas furnace (which puts out fumes about 20 feet from the monitor) are settling near the monitor. But that’s only a guess. Any other suggestions on how to interpret these data?
