Roughly seven weeks ago we had the popcorn ceilings of our house removed. The contractor primed with one coat of Kilz Original Oil Based Primer (SDS) and then used two coats of Sherwin Williams Promar 400 Zero VOC (flat, no tint) (SDS). The Kilz has a lot of VOCs and smelled a bunch (kind of like kerosene) after it went on but diminished quickly. Immediately after the two coats of the Promar there was a noticeable but different paint smell.
Since we've had fans in the windows providing several hundred CFM of ventilation at most times. The temperature has ranged from the 70s to the mid 90s (~20-35 C) over a range of humidities (this is in the Carolinas).
We started measuring the total VOCs about a week and a half later with three separate instruments. Initially we saw readings of about 0.03 mg/m^2 on two sensors and for the past several weeks they have been reading at the bottom of the scale - 0.01 mg/m^2. (The 3rd sensor is the Experimental Bosch Static IAQ sensor on a new Purpleair which reads on a different scale and tends on wander around, but it shows the same values indoor and out).
Despite the VOC readings being below the detection limit of these sensors, there's still a very slight lingering smell. Any ideas what this might be from? We're trying to figure out if this might be from some VOC that it's possible to smell even at very low concentrations, or from some other source (like the synthetic latex in the paint).
