Roundup: Northern Italy bans most polluting vehicles due to heavy fog

Many weeks of dry weather in often rainy northern Italy have pushed fog and pollution to a critical level, prompting a ban on vehicles and other special measures.

Industrial cities Milan and Turin as well as various nearby smaller towns have decreed a block on the most polluting vehicles and allowed free circulation on subway, buses and trams.

In the Po Valley, where Milan and other northern cities are located, fog is a frequent phenomenon because of the lay of the land, Colonel Guido Guidi, weather and climate expert of the Italian Air Force, explained to Xinhua.

This sunny autumn was particularly foggy, he said, as persisting high pressure combined with lacking flow of air generates a temperature inversion which increases the water vapor confinement in the lowest layers of the atmosphere.

However, there is a close relation between fog and pollution, Guidi noted.

The infinitesimal droplets that form the fog, he elaborated, are influenced by the presence of fine dust, that is to say minuscule solid particles which lead to the formation of droplets. These solid particles can be of natural origin but also of anthropic origin, meaning particulate matter (PM) of different sizes.

The more water vapor and PM both increase, the more the probability of fog formation increases too, Guidi said.

After several successive days of rising pollution levels, Milan banned the most polluting vehicles - Euro 3-class diesels with no anti-particle filters - in different time slots both for private use and for commercial traffic.

Sources from the Milan municipality explained to Xinhua that central heating units must be adjusted down one degree from 20 to 19 degrees Celsius, and the heating time lowered from 14 to 12 hours per day.

"Another two extraordinary measures were the disposal free of charge of buses and trams for adults taking children up to 10 - already traveling free - to school and of the bicycle-sharing scheme," the sources also added.

They said an improvement of air quality has been registered in the last three years in Milan, thanks to a road pricing measure launched in the city center which reduced by more than 30 percent the vehicles inside the designated restricted zone.

Compared to 2010, last year PM10 emissions for vehicles decreased 38 percent, according to official estimates. District heating and a low emission zone to monitor the access of big vehicles were other effective measures introduced to reduce pollution.

With some 7,000 shared cars, bikes and scooters, Milan has recently won the Euro - China Smart Mobility city Award 2015, which rewards European and Chinese cities for their commitments and achievements regarding eco-mobility. Enditem