The amount of land ravaged in Portugal's recent devastating wildfires is estimated to cover 122,000 hectares. Around 83% of the land is located in the north and centre of the country.

These tiny solid or liquid particles in the atmosphere increase with fire activity, and can reduce visibility and impact health

Thousands of firefighters tackling deadly wildfires in central and northern Portugal had largely doused the flames in the Aveiro district, one of the worst-hit, as of Thursday morning, and were focusing on a dozen blazes still raging elsewhere.