Residents within two kilometres of a fire in St Margarets are being urged to close their windows.
People with breathing difficulties are also being warned about the blaze at a car scrap yard near the airport.
It's being brought under control now with no injuries reported, and flights remain unaffected.
But Dublin Fire Brigade's James Mulholland says the smoke contains danger gases:
"With the plastics that are used in modern cars, you'll get additional very hazardous chemicals released. All our firefighters will use breathing apparatus when they're putting out this fire. But the gases will come back down to earth and there's a risk of getting into people's homes."