MISSOULA, Mont. -

There is an inevitable day in the Missoula Valley every summer when residents will cough and wheeze as smoke from any number of wildfires settles over Montana's 2nd largest city.

Farther south in the Bitterroot Valley, it can be even worse. It's why the Missoula City-County Health Department keeps two air quality experts on its staff.

NBC Montana caught up with Air Quality Specialist Sarah Coefield on Monday at a speaking event for the City Club of Missoula.  She says the longer fire seasons in recent years -- sometimes over a month longer -- have made air quality a larger issue than it was in the past.

Missoula County starts issuing alerts for unhealthy air, mainly due to smoke, when the pollution level is 30 percent lower than the standards set by the Environmental Protection Agency. Those standards are a measurement of how many particulates are in the air.

The ones from industrial pollution and wildfire smoke are dangerous for anyone to breathe. People with respiratory problems are especially at risk.

Coefield says the Health Department does not encourage wearing masks if you want to venture outside during a smoky day. She says your common surgical or dust masks aren't able to block the fine particles in the smoke the cause lung problems. The solution is what's called a respirator. It's a high-grade mask that filters out much smaller particles. The Health Department advises those especially at risk to stay indoors during days with poor air quality.