The maps use different inputs
AirNow maps are built from monitoring and reporting systems that observe ambient pollutants at specific sites or reporting areas. HRRR-Smoke begins with fire-emission estimates and weather-model physics. One describes recent observed air quality; the other predicts smoke-related particle mass on a grid.
Because monitoring stations are not located at every address, the nearest AirNow reporting area may be miles from the forecast point. Because HRRR cells are approximately 3 kilometers wide, the smoke model also cannot represent every street, valley, or neighborhood. Both require geographic context.
AQI is not micrograms of modeled smoke
AQI is a standardized index with official categories and health messaging. A reporting area’s primary pollutant may be PM2.5, PM10, or ozone. Near-surface HRRR-Smoke is modeled primary fire-emitted fine-particle mass in micrograms per cubic meter. It is not total PM2.5 and cannot be converted directly into AQI by this app.
Smoke Window deliberately gives the model and AirNow separate panels. Official AQI colors and category names belong only to the observation. The model legend uses numeric bands and explicitly says it is not AQI.
Use both without forcing agreement
The smoke map can suggest how a plume may move over the next 48 hours. The air-quality map can show what a nearby reporting area has recently observed. Agreement can strengthen a broad interpretation, but disagreement is informative too: the plume may be elevated, the monitor may be outside the modeled feature, or another pollutant may drive AQI.
Check valid times before comparing. AirNow’s NowCast incorporates multiple recent hours, while a model frame represents a particular forecast time. The two products are not synchronized measurements of the same quantity.
Why the legends should look different
Official AQI colors carry standardized category and health meanings. Reusing those category names for a smoke-model layer would encourage a false conversion between modeled smoke mass and observed air quality. Smoke Window labels its own numeric bands and explicitly marks them “not AQI.” The AirNow panel alone uses official AQI category language. Reading the legend title before the colors is the fastest way to identify which product is on screen.
Points, reporting areas, and grids
An air-quality monitor measures at a physical site, and AirNow may aggregate that information into a reporting area. A smoke model estimates every cell on a regular atmospheric grid. The two geometries answer different spatial questions. A monitor can capture local emissions the grid does not resolve, while a grid can depict a regional plume between sparse monitors. Neither should be described as an exact reading for every address inside a city or county.
Current maps and future maps
AirNow emphasizes recent observed conditions through the NowCast, while HRRR-Smoke extends into future forecast hours. Comparing a current observation with a frame valid tomorrow will create an apparent disagreement that is only a time mismatch. First align valid times as closely as the products allow. Then use the model for movement and the observation for present context. A future AQI forecast, when issued by an air agency, is a third distinct product.
What causes apparent contradictions
Modeled smoke may be elevated above the monitor, displaced by a grid-cell error, or predicted before arrival. AQI may be high because of ozone, dust, urban particles, or smoke not captured well in the emission estimate. The AirNow site may also be far from the chosen point. These are testable explanations: inspect primary pollutant, reporting distance, model time, surrounding cells, and official local commentary before deciding that either map is broken.
Choosing the right map quickly
For “what has a nearby station recently observed?”, choose the AirNow map. For “where might modeled fire particles move over the next two days?”, choose the HRRR-Smoke map. For “which incidents are officially reported?”, choose WFIGS or incident-agency products. For “is this activity appropriate for me?”, begin with official air-quality and health guidance. Smoke Window places these layers together while keeping their units, times, and claims separate.
Bottom line: air quality map vs smoke map
A quick final check is to read the legend’s noun: AQI or modeled smoke concentration. Then read the time and geography. Those three labels prevent most category mistakes. Air-quality maps serve observed pollutant and health communication; smoke maps serve transport and timing. Keeping both available but visually and verbally separate gives users more context than blending them into a single color that cannot honestly represent either product.
A careful reading of air quality map vs smoke map
An air-quality map summarizes observed pollutant conditions as AQI. A smoke map estimates smoke-specific mass through space and future time. They answer different questions. Keep that immediate answer attached to the valid time, selected geography, model run, and product limits described above. Those details are part of the result, not fine print, and they should travel with any shared interpretation of this guide.