A report released this week from EU-body the European Environment Agency (EEA) found the highest levels of natural pollutants were in Spain, which frequently experiences forest fires, most recently this month.
Of 42 instances where the levels in Spain were reported above legal limits, 18 were caused by natural pollution, said the report, which is the first European study of its kind.
Spain’s proximity to the Sahara desert makes it especially vulnerable, said the Observatory of Sustainability, an independent organisation in Spain.
“This will get worse [due to] desertification caused by climate change in the peninsula, converting this topic to a very important issue in Spain,” the group said in a statement.
Ten other countries - including Cyprus, Greece and Italy - also reported air pollution above legal limits because of natural particles.
“This analysis shows that authorities should make extra efforts to reduce the air pollution they can control, because the cumulative effect of natural and man-made particulates can damage people's health,” Jacqueline McGlade, EAA’s executive director said.
While pollution from sea spray and sand result from natural phenomena, 90% of forest fires are caused by humans, as estimated by the EU research organisation.
But if wind carries the smoke and particles from fires into other countries, they are classed as natural pollution.
"From time to time there are events with very high levels of particulate matter that cannot be explained by local sources," said Panos Hadjinicolaou, a researcher at the Cyprus Institute.
The World Health Organization reports health problems from short-term exposure can cause breathing difficulty, where long-term exposure can decrease lung function and shorten life expectancy. The Observatory of Sustainability reported that in Spain the particles have been connected to asthma in children and premature deaths.
First adopted in 2005, the EU's Air Quality Directive requires a 20% reduction in air pollution by 2020.
The directive allows member states to subtract pollution from natural sources from the numbers they report to the European Commission, but each country measures man-made pollutants and natural pollution differently, making it difficult to evaluate consistently.