Air Quality Alert?
The only place in the USA that is having an air quality warning tomorrow is Maryland so we can assume that is where you are located. The reason for the alert is: because of an inversion, and the wintertime buildup of smoke and emissions in the atmosphere from home heating plants. - it's related to rising temperatures and low/high pressure. Here is an article about it: https://www.baltimoresun.com/news/weather/bs-md-air-quality-alert-20190203-story.html
Winter air quality issues are generally caused by a temperature inversion, where cooler air near surface gets trapped in place by warmer air up high. Normally, the higher you go, the colder the air gets, and the cold air sinks. Warm fronts tend to arrive in a wedge shape that can put warm air above colder air at ground level, and prevent the normal mixing process. the cooler air at surface doesn't go anywhere, at least until the front passes through and returns the temperature gradient back to normal. Sometimes this happens with a stationary front, and then you can get air quality problems for basically the same reason. it is the length of time that the normal air mixing gets blocked which is the source of the problem. It takes time for air pollutants to build up in concentration, and they will build up if they aren't getting flushed away. Need nature to unclog the air toilet flusher.
I would presume because the air quality is bad. Why should they be confined to the summer ? Are there any fewer vehicles on the streets in winter? Do people use less fuel and less energy in the winter ? Why do YOU think air quality depends upon the season?