As you may have noticed, this year is one of the most polluted in history.

The U.S. Environmental Protection Agency has declared a national emergency for the entire country, which is why the Trump administration has been taking all sorts of precautions to try and contain the problem.

But in many places, air purification systems are only part of the problem: There’s also the pollution itself.

The Environmental Protection Department has issued more than 200 advisories in the past year, according to the Los Angeles Times, but it’s not enough.

“In terms of the scope of the pollution problem, there’s not really much that can be done to clean up it,” Matt Miller, a senior attorney at the Natural Resources Defense Council, told The Verge.

In California, the pollution is particularly egregious.

The state is home to some of the largest concentrations of coal ash, and while some cities are dealing with their own problems, Los Angeles is a prime example of a city where the pollution level is so extreme that the state’s air quality management program has issued “no confidence” ratings for more than half the cities in the state.

(Los Angeles is one state that has yet to issue a no-confidence rating for the city’s coal ash pollution.)

This pollution is already impacting California’s tourism industry.

“We are really concerned about the potential for coal ash to migrate into communities that are not currently affected by coal ash,” Dan Wesson, a spokesperson for the California Department of Forestry and Fire Protection told The LA Times.

The Los Angeles area is also home to a massive coal ash storage facility that’s been burning for more, and the state is now considering requiring it to shut down, Wesson said.

As for the dust from the ash being transported from coal plants, it can spread into areas that aren’t covered by the ash.

“When you’re not covering the dust with dusts that have already been washed off, then the dusts can easily become airborne,” Miller said.

Even with all of the precautions being taken to prevent the spread of air pollution, Miller said, there are still some places where coal ash can still be found.

“The best bet is to take a walk in a forest and look for it,” he said.