Toxic fog hits Utah: Pregnant women and children urged to stay indoors as pollution goes 'off the charts' in freezing weather



Health emergency declared Utah where pollution is now the worst in America

The greater Salt Lake region had up to 130 micrograms of soot per cubic meter - more than three times the federal clean-air limit

More than 100 Utah doctors are calling for immediate action



Two million people are at risk from a toxic fog that has descended over Utah as pollution levels in Salt Lake City reach an all-time high.



The icy fog has smothered the Salt Lake Valley for several weeks and trapped lung-busting soot emitted in the city underneath.

The level of pollution in the city is now the highest in America according to the Environmental Protection Agency and medical experts are now urging residents to stay indoors.

Health emergency: A toxic cloud caused by fog trapping pollution underneath hangs over Salt Lake City

Warning: Doctors - including Dr Gary Kunkel, pictured - are urging Utah residents to stay indoors to avoid inhaling the toxic air over

The smog over Salt Lake City has been caused by a temperature inversion - where warmer air creates a barrier above cold fog so everything underneath is trapped

The smog over Salt Lake City, which is surrounded by the Wasatch and Oquirrh mountain ranges, has been caused by a temperature inversion where warmer air has created a barrier above cold fog so everything underneath is trapped.

Snow cover on the surrounding mountains has amplified the phenomena, leaving Salt Lake City at just 18 degrees while Park City basks in sunny 43-degree weather.

The warmer air aloft has acted like a lid on the frigid valley air, leaving it with no place to go.

The pollution is now getting so bad that more than 100 Utah doctors are calling for authorities to immediately lower highway speed limits, curb industrial activity and make mass transit free for the rest of winter.



Travelwise: Residents have already been asked to cut down their travel to prevent more petrol emissions adding to the pollution

Off the charts: There are now 130 micrograms of soot per cubic meter in Salt Lake City - three times the federal clean-air limit

Doctors say the microscopic soot - a shower of combustion particles from tailpipe and other emissions - can tax the lungs of even healthy people.



'We're in a public-health emergency for much of the winter,' said Brian Moench, a 62-year-old anesthesiologist and president of Utah Physicians for a Healthy Environment, which delivered the petition demanding action at the Utah Capitol.



The greater Salt Lake region had up to 130 micrograms of soot per cubic meter - more than three times the federal clean-air limit, according to the U.S. Environmental Protection Agency.



And for two million Utah residents, there is no escape from the fog, except to the snow-capped mountains surrounding the city or resort towns like Park City, where the Sundance Film Festival is under way.



Dangerous: Doctors warn the pollution levels are still toxic to people without any health issues

Capped: The polluted fog is trapped under a warmer layer of air that is acting like a lid on top of cooler air

Authorities have already prohibited wood burning and urged people to limit driving. Vehicle emissions account for more than half of the trapped pollutants.



Utah regulators are working on a set of plans to limit everyday emissions, including a measure to ban the sale of aerosol deodorants and hair spray that contain hydrocarbon propellants.



Those plans, however, will take years to show results.



Doctors say people - especially pregnant women and children - should stay indoors, or at least avoid active outdoor exercise under the sickening yellowish haze. Elderly people with heart disease are most at risk, Moench said.



The most polluted: The U.S. Environmental Protection Agency has singled out the greater Salt Lake region as having America's worst levels of pollution

Above the fog: The air around the mountains above Salt Lake City - on of America's top ski resorts - is completely clear

Time for change: Salt Lake City residents have already been prohibited from wood burning but doctors are calling for more stringent measures

'If you can see it, you don't want to breathe it. Think about what's going into your body,' Salt Lake City pediatrician Ellie Brownstein said.

'It's essentially like smoking. Instead of breathing clean air, you're breathing particles that make it harder for your lungs to function and get oxygen.'

CAUSE OF THE TOXIC FOG Smog is caused by a weather phenomenon known as an inversion layer. This happens when warm air mass moves over the top of an area with cooler air. The warmer air then acts like a lid on top - effectively trapping everything underneath. Over cities, this then causes a build-up of pollution as fumes and emissions have no where to escape to.

Severe inversions can last for several weeks and cause respiratory problems for the inhabitants in the areas trapped underneath.

A previous example of this happening was the Great Smog of London in 1952 which caused thousands of deaths.





For weeks, industrialized cities in northern China have been dealing with bouts of sickening smog several times more toxic than Utah's.



But by U.S. standards, Utah's pollution index is off the charts with readings routinely exceeding a scale that tops out at 70 micrograms a cubic meter.



The EPA sets a standard for clean air at no more than 35 micrograms.

'People think the health implications are limited to asthma - that's only a drop in the bucket,' Moench said.



'For every pregnant woman breathing this stuff, this is a threat to her fetus through chromosome damage.



'It sets people up for a lifelong propensity for all sorts of diseases.'

Mother Michelle Francis has seen the effects of the toxic fog firsthand as her nine-year-old daughter now suffers from chronic asthma.

The air pollution is so awful in her Salt Lake City suburb that Francis keeps her daughter indoors on many days to prevent her cough from being aggravated.



'When you add all the gunk in the air, it's too much,' Francis said.



The Utah health emergency comes as a deep arctic freeze has locked parts of the Midwest to the Northeast in their fourth day of glacial temperatures felt as low as -36F degrees.



In Chicago, water froze on firefighters’ gloves almost as soon as it left their hoses as they attempted to battle a fire, while an entire façade of a building located on the city’s South Side was coated in sheets of ice.



In New York's Manhattan, commuters similarly woke to temperatures around 12-degrees today, but with wind gusts of 15-20 mph, it felt more like five below as people started their work day.



The cold snap arrived on Saturday night as waves of Arctic air swept south from Canada, pushing temperatures to dangerous lows and leaving a section of the country well-versed in winter's pains reeling.



It is expected to last several more days.



Cold snap: Trucks in Chicago are frozen in place under sheets of ice as an Arctic blast continues to grip the U.S. Midwest and Northeast

Frozen to the spot: Temperatures have dropped as low as 50 degrees below zero Fahrenheit (-46C)

Tricky situation: Firefighters were attempting to tackle a blaze at this warehouse in Chicago but their water froze as soon as it left the hoses







