- There is a higher level of PM2.5 pollution outside of the house. Readings are in the 80-150 range due to wildfires. (PM2.5 levels determined by sensors in PurpleAir.com's sensor network)
- Using a handheld air monitor that can measure PM2.5 readings were taken indoors.
- Most rooms in the house are reading +/- 40, but one room read 450
- smokey haze could be seen in the room during the highest readings (what alerted us to the problem)
- relative humidity outside is typically low (30-40%)
- the room with the high reading (450 PM2.5) has
- high humidity (80-90%) to support tropical plants
- windows from the 1990s (older, don't seal well)
- an attic access panel that allows some air movement
- no fans that would draw in air from outside or push air outside
- room is long and skinny (40'x15') with windows along the long axis and has a door halfway down the 40' axis
- one end has higher humidity (where the humidifier is)
- putting 3 small HEPA filters in the room can reduce PM2.5 to 5 in about an hour. After about 10 hours, readings of PM2.5 are much higher 80-400
- if we reduce the PM2.5 to under 10 and close the door halfway along the 40' axis of the room, the lower humidity side of the door stays free of PM2.5 whereas the PM2.5 on the higher humidity side of the door continues to increase.
- there is no internal source of PM2.5 - this only started this week as smoke has blown into the area
Q: what's the likelihood that the humidity differential between indoors and outdoors is "pumping" air and effectively pulling smoke indoors?
Q. What's the likelihood of the humidity differential being able to concentrate the smoke indoors (there have been no readings outside that come close to the 450 PM2.5 that was seen indoors, could the humidity differential be "pumping" pollution indoors and concentrating it)?
Q. what else might be contributing or causing this?