A thick layer of wildfire smoke recently turned the Hastings sky hazy, reduced visibility and pushed the city’s
Air Quality Index reading to 444, a level considered hazardous for everyone. On July 16, the smoke moved south from large wildfires burning in northeastern Minnesota, including fires in
and around the Boundary Waters Canoe Area Wilderness, along with additional fires in Canada. Weather
conditions carried the smoke across much of Minnesota, bringing some of the poorest air quality the state has
experienced in recent years.
The unexpected AQI warnings forced organizers of many outdoor events to cancel for the day. The biggest
cancellation was for the annual kickoff to Rivertown Days event at the LeDuc Mansion property. The event, sponsored by Culvers and Merchants Bank, feeds and entertains nearly 1,000 area residents to start the Rivertown Days festivities each year. Organizers acted quickly and responsibly to get the word out to folks when it looked as though the air quality was going to be a problem for the entire day. Other organizations cancelled outdoor events including the state lacrosse organization which cancelled all youth lacrosse statewide. HYAA cancelled all baseball and softball games and practices for the day as well. For residents watching air quality maps, a reading of 444 can be startling, especially when a typical summer day may show a reading below 50. Understanding the Air Quality Index, commonly called the AQI, can help
residents decide when it is safe to spend time outside and when it may be better to remain indoors.
The AQI is a scale used to describe how clean or polluted the outdoor air is. It generally runs from zero to 500,
with higher numbers indicating more pollution and a greater risk of health problems. An AQI reading between zero and 50 is considered good. Air pollution at that level poses little or no risk, and normal outdoor activities can continue. Readings between 51 and 100 are considered moderate. The air remains acceptable for most people, although a small number of people who are unusually sensitive to air pollution may experience symptoms. The next level, between 101 and 150, is classified as unhealthy for sensitive groups. That category includes children, older adults, pregnant people and those with heart or lung conditions. People in those groups may need to reduce long or strenuous outdoor activities. Readings between 151 and 200 are considered unhealthy. At that point, everyone may begin to experience health effects, while people in sensitive groups face a greater chance of more serious symptoms. An AQI between 201 and 300 is classified as very unhealthy. Health officials may issue stronger warnings
during those conditions, and residents are encouraged to avoid strenuous outdoor activity. Anything from 301 to 500 falls into the hazardous category. An AQI of 444, like the reading reported in Hastings, is well within that range and near the upper end of the standard scale. Hazardous air quality is treated as an emergency condition because everyone can be affected, not only those with existing medical conditions.
Wildfire smoke contains fine particulate matter, often identified as PM2.5. Those particles are much smaller
than a grain of sand and can travel deep into the lungs. Some particles may also enter the bloodstream. Exposure can cause coughing, wheezing, shortness of breath, headaches, fatigue and irritation of the eyes, nose or throat. People with asthma, chronic obstructive pulmonary disease, heart disease or other health conditions may experience more serious effects.
At an AQI of 444, residents should avoid outdoor physical activity whenever possible. Children’s sports practices, outdoor workouts, yardwork and other strenuous activities should be moved indoors, postponed or shortened.

Remaining indoors does not completely eliminate exposure, because smoke can enter through open windows,
doors and ventilation systems. Closing windows and doors, running an air conditioner on a recirculation setting
and using a properly rated air filter can help improve indoor air. Residents should avoid activities that create additional indoor pollution, including smoking, burning candles, using wood-burning fireplaces and excessive frying or grilling. A portable air cleaner can also help reduce fine particles in a frequently used room.
People who must be outdoors may receive some protection from a properly fitted N95 or similar respirator. Cloth masks and loose-fitting face coverings generally do not filter the smallest smoke particles effectively. Pets can also be affected by wildfire smoke. Dogs should be taken outside only long enough for necessary breaks during hazardous conditions, and strenuous walks or play should be avoided. Animals with heart or breathing problems, older pets and short-nosed breeds may be especially vulnerable. Air quality can change quickly as winds shift and smoke concentrations move through an area. A hazy morning may improve during the afternoon, or apparently clear conditions may deteriorate within a few hours. Residents should check current local readings before beginning outdoor activities. 
The AQI reading of 444 provided Hastings residents with an extreme example of what the index is designed to
communicate. At the lower levels, the colors and numbers offer general guidance. At the hazardous level, the
message becomes much simpler, the air is unsafe, and outdoor exposure should be kept to a minimum. The recent smoke cleared as weather patterns changed, but wildfires can continue producing smoke for weeks or months. Future smoke events will depend on fire activity, wind direction, rainfall and atmospheric conditions.
For Hastings residents, learning the AQI scale now can make the next smoky day easier to understand. Green and yellow readings generally allow normal activities, orange calls for caution among sensitive groups, red and purple require increasingly serious precautions, and maroon means everyone should take steps to avoid exposure.
For those looking to add Air Quality Index monitoring to their weather observations, visit www.airnow.gov or install the AirNow app on your mobile device. Both the app and website give you important information regarding the current air quality and what types of pollutants there are in the air.