The state of Washington uses a separate indexing system called the Washington Air Quality Advisory (WAQA). The WAQA considers lower particulate concentrations more harmful to human health than the federal AQI, but otherwise follows the AQI. This is a better reflection of best available science since we know that it is the very small microscopic particles that are ingested most deeply into our lungs and do the most damage.

And just to make things more fun for everyone, the Northwest Clean Air Agency readings do not always match what you will find from the Washington Department of Ecology. And there are also differences between the various state clean air agencies. For example, the Puget Sound Air Agency (for South Puget Sound) tends to be very pro-active and the NWCAA much less so.

Another problem is that in most cases, but not in this one, air quality impacts are very localized, and there may be big smoke problems on one block but none a few blocks away, depending on who is heating with wood, or using a fire pit, or air flow patterns.

Most of Whatcom County is in the Frasier Valley air shed, although the most southern end of the County, from the Chuckanuts south, is in the Skagit Valley air shed. So the best thing to do is rely on your own senses. If you smell smoke, or see smoke (more than the thinnest of wisps.. more of an impression in the air really), then you are being exposed to harmful air pollution, and the more extreme the smell, the smoke, the haze, etc. the worse the air pollution has become.