Deadly New Delhi Air Pollution Keeps Getting Worse

At certain times of year, some immense cities in the world become cesspools of extreme air pollution, putting the lives of millions of people in danger.

Extreme air pollution in India this past week. Photo by Arushree
Fadnavis./Reuters

In recent days, New Delhi, India has probably topped them all. The pollution was so thick, so dangerous, that you couldn't measure it.

A widely used air qualilty index measures ground level ozone, particulates, carbon monoxide, sulfer dioxide and nitrogen dioxide.  If the index is at 50 or lower, the air is clean and great to breath.

Up to 300, the air is a bit iffy - unhealthy for people with underlying health issues or other sensitivities, but the rest of us can probably manage, though with some potential health effects. If you get over 300, the air is downright dangerous for everybody.

We don't know how high the air quality index got in New Delhi, because the measuring devices only go to 999. I imagine the pollution levels were at least four times higher than what is considered dangerous for everybody.

 Here's how Time magazine describes what this is like:

"By one estimate, breathing Delhi's air for one day has the health impacts of smoking at least 25 cigarettes. Although Delhi typically experiences marked increases in air pollution around Novermber, this year's pollution prompted Delhi's Chief Minister, Arvind Kejriwal to call the city a 'gas chamber.'"

Time says New Delhi's experience with air pollution is part of a global trend that is causing roughly 7 million premature deaths annually.

Inversions, in which warm air traps cooler air beneath it, is the root meteorological cause of these pollution episodes. That warm air aloft acts as a lid so that pollutants can't escape and blow away. As cars, trucks, agricultural fires, factories and everything else loft stuff into the air, it just accumulates under this "lid," with toxic results.

In New Delhi's case, it started with an annual celebration called Diwali, in which lots of people set of fireworks. Those add a lot of smoke to the air.

This is also the time of year that farmers in land surrounding New Delhi to set fires in fields to clear land for the next round of crops.  Add to it the millions of cars, trucks, factories and scooter and you get a real disaster.

By the way, we here in Vermont are not immune from pollution problems caused by inversions.  These inversions often happen in the winter.  That can trap pollutants from things like cars and wood stove smoke in our Green Mountain valleys, elevating pollution levels.

The area around Rutland, for instance, is shaped like a bowl, and is sometimes subject to wintertime air pollution alerts. Of course, and thankfully, Rutland will never get as bad as New Delhi.

Blame Out Of Season Temperature Inversion On Dank Vermont Weather

Spring flowers in my St. Albans, Vermont perennial gardens and bright
flags on my deck try to brighten up a very dreary Thursday
afternoon, but they can only do so much. 

For almost all of us Vermonters, this Thursday morning and afternoon has been an unpleasant exercise in chill, damp, clouds, fog and drizzle.  It's not the type of bright, blossomy May weather we expect, and feel entitled to this time of year.  

Blame it on a temperature inversion. It's warmer a few thousand feet up above us than it is near the surface.

This is the opposite of the usual regime, where it gets progressively colder the more you go up in elevation.

The warm-ish air up above locks us in the thick, chilly moisture and mist, as the atmosphere can't mix. Drier up above can't penetrate the "lid" the temperature inversion forms.

Since the drier air can't work its way down to us, it can't clear the clouds. The sun can't penetrate to warm us up. So, yuck.

These inversions are pretty typical in the late fall and winter. At that time of year, the sun angle is low and the light is weak.  If the sun is able to warm the air near the surface, it starts to rise, poking holes in the inversion up above until it finally breaks apart. In the winter, the sun just doesn't have the strength to pull that off.

The sun angle this time of year is much higher, so inversions are more rare. The sun usually can burst through, offering us a jail break from the gloom. Not today. The inversion is just too strong.

There's a slow moving weather front just to our south. Warmer air is feeding up and over that front and gliding northward, keeping that inversion sustained, despite what the sun wants to do.

South of the front, it's mild. It was 60 degrees at mid-afternoon in Bennington, which is just south of the front. Not super warm for early May, but much better than the March-like foggy 40s in the rest of Vermont.

So far today, the high temperature in Burlington was 45 degrees. That's not far from the coldest high temperature on record for the date, which was 41 degrees in 1953.

The inversion will break up tomorrow as a new, relatively weak storm comes in from the west and southwest. It will be a bit warmer Friday, but the overall weather won't improve much. It'll be in the 50s during the day - still a little chilly for this time of year. And there will be a lot of light rain and showers around.

You won't see the sun, so if you're craving it, you're out of luck.

Until Saturday, that is. By then, a little clearing will at least temporarily work in. The afternoon that day will feature some sun, and temperatures near 60 degrees. That's not too far from normal, so that's good.

With the forecasted sun and comfortable temperatures Saturday, it will be great if you want to participate in Vermont's Green-Up Day. That's when thousands of volunteers go out and clean up roadside trash. You ought to consider joining in.

But the weather pattern will remain active. We might not have more foggy, dank and drizzly inversions like we're having this afternoon, but we will have frequent bouts of clouds and showers for at least the next week or so.

New Delhi, India, Choking In Toxic Smog

Thick smog in New Delhi this month. Photo by Altaf
Qadri/Associated Press

In 1952, a deadly smog enveloped London, England.   

In those days, coal and polluting fuels heated homes and businesses and basically powered the city.

During one of those famous London fogs, all those pollutants got trapped within the fog, causing a four-day dense cloud of smog that killed an estimated 4,000 people.

London has literally cleaned up its act, and pollution there rarely gets to dangerous levels.

Not so in other cities in the world.  Beijing, China is famous for its toxic pollution.

So is New Delhi, India, which is now enveloped in a smog so bad that it's being compared to that terrible London smog of 1952.

The smog cloud in New Delhi, like most pollution outbreaks is caused by an inversion, which is warm air over the top of cooler air that acts like a lid, preventing pollutants and smoke and such from rising and moving away. So it sits there.

Illegal crop burning at farms surrounding New Delhi, vehicle emissions and construction activity and dust are pouring into the New Delhi air, and the pollutants keep accumulating under this inversion.

The Straights Times says New Delhi is trying to deal with the immediate crisis by reducing the number of cars allowed to be driven on its streets each day, banning commercial trucks unless they're carrying essential commodities, new construction has been stopped and charges for parking cars has quadrupled to force people into public transportation. Schools are shut down.

But that's not really doing the trick. There has been a 20 percent spike in hospitalizations due to heart and lung problems. The amount of microscopic particles in the polluted air is 75 times what the World Health Organization considers safe. Breathing the air is the equivalent of smoking two packs of cigarettes per day. 

And this pollution attack isn't a one-off. It's happening with increasing frequency in New Delhi and other cities in India and elsewhere in Asia.

And remember how I said London and England's air is cleaner? That's true, but it's still too polluted even there. Of 51 British towns and cities in a WHO database, 44 have too much air pollution, the Independent said.

Meanwhile, in the United States, air quality has also improved since the 1960s and 1970s but still sometimes falls short.

Don't expect even cleaner U.S. air in the coming years. Robert Phalen is an appointee to a Trump White House environmental panel. Phalen has said that "Modern air is a little too clean for optimum health."

He claims that children should be exposed to some dirty air to teach their immunie systems to ward off irritants, or something like that.

Hope you love breathing microscopic, toxic particles, folks!

Inversions A Wintertime Topsy Turvy Fog And Smog Creator

This visible satellite image taken Sunday morning
and provided by the National Weather Service in
Burlington, Vermont shows low clouds
and fog in the valleys, and clear skies
in the higher elevations. 

Here in Vermont on Sunday, the early morning forecast called for sunny skies during the day with unseasonably warm temperatures.

That forecast proved spot on, especially in higher elevations. Some of the state's valleys, however, stayed foggy, overcast and chilly most of the day.

What happened? It's called a temperature nversion, and they are generally most common this time of year, when the sun angle is low and the days are short.

Normally, the temperature drops as you go up in elevation.  Sometimes, though, there's a layer of warmer air above some chilly air trapped in lower spots, like valleys. The normal elevation temperature regime is inverted. You have an official inversion. Congratulations!

Inversions happen often at night, when cold air drains down into valleys on clear, calm nights. These inversions usually break up quickly in the morning, especially in the warmer times of the year.

That's because the sun comes up, heats the air right near the ground, which starts to rise, which mixes with the warm air above. The atmosphere in these cases sorts itself out, and you go back to the normal circumstances of it getting colder as you get higher up.

This time of year, though, the sun angle is pretty much at its lowest point. The sun isn't able to heat the ground easily, and it's not above the horizon for all that long. Which means it's sometimes too feeble to break the inversion.

That happened in much of the Northeast Sunday, and it was happening again in parts of eastern New England this morning.

For much of Sunday morning, the landscape was shrouded n many areas by dense fog or dense freezing fog.

Freezing fog is merely fog that occurs when the temperature is below freezing. Water droplets that make up the fog stay in liquid form despite the subfreezing tempertures. The droplets stay in liquid form, that is, until they touch something, when the instantly freeze.

The frozen droplets in dense fog cause beautiful rime ice on trees, but also black ice on roadways.  The beauty and the beast, I guess.

On Sunday, mid and high elevations in the Northeast in the warm air above the valley chill  enjoyed a sunny, mild day. The inversion also broke up in some valleys when enough sun broke through to disrupt the inversion.

Other areas stayed firmly in the foggy inversion. Montpelier, Vermont, for instance, had fog or freezing fog pretty much all day Sunday, and the temperature only barely rose above freezing to a high of 34 degrees.

However, Saranac Lake, New York, at a relatively high elevation and normally the coldest reporting station in the North Country, reached a sunny 45 degrees Sunday afternoon.

Another danger from temperature inversions is pollution, especially if the inversion lasts a long time.

I was in Rutland, Vermont on Sunday. The inversion sort of broke for a time, and the fog lifted. But the inversion re-established itself. It was dry enough by then that fog did not re-form.

But with so many people burning wood to heat their homes, and cars driving around and such, you could actually see a layer of brown smog hugging the populated valley floors around Rutland, West Rutland and Proctor.

Believe it or not, considering we're talking about "clean" Vermont, the area around Rutland in particular is prone to air pollution alerts in the winter because that valley is especially likely to get some persistent inversions during the cold season.

Elsewhere in the world, inversions can be more persistent, and last much longer. Salt Lake City, Utah often goes for days and days on end shrouded in fog and smog as inverstions take hold in the Salt Lake Valley.

And the type of dangerous, thick smog that has blanketed Beijing, China recently is also a product of wintertime temperature inversions.  I'm told the smog is back big time in today in Beijing, too.

This kind of thing used to happen in the United States, too. Most famously the industrial town of Denora, Pennsylvania suffered a smog inversion that killed perhaps 20 people and sickened thousands more in the late autumn of 1948.

Here in the Northeast, wintertime inversions usually don't last long. A storm system will come along with a bunch of wind, and the wind mixes up the atmosphere and breaks up the inversion. However, even then, inversions are a risk.

When a storm has a warm front approaching your area in the winter, sometimes onrushing mild air, which is lighter, goes up and over the dense cold air near the surface. The result is dangerous freezing rain.

Calm high pressure is likely to hold over much of the Northeast for at least the first half of this week, so we're likely to see more inversions, more fog or freezing fog, and maybe some smog in spots.

It's one of those cases that if you like sunny, mild weather this time of year, head for the hills.







except in  of the state's all

Incredible New England Inversion Freezes Valleys, Mountains Bask In "Warmth"

This photo shows an inversion trapping pollutants
in the Salt Lake City valley, while the air is
clear above the inversion. Photo from the
National Center for Atmospheric Research.  

Skiers who live in valleys beneath northern New England and northern New York mountains had to get up early this morning and try to start their cars amid temperatures in the teens and 20s below zero.  

Very frigid. Among the coldest mornings of the winter.  

Meanwhile, up at the summits of those mountains those freezing skiers wished to go to, temperatures were in the upper single numbers and teens above zero.

In Whiteville, NH. this morning, it was 21 below. The 6,000-foot summit elevation of Mt. Washington was 12 above.

In the valley at Morrisville, Vermont, the temperature at 7 a.m. was 21 below. A dozen or so miles away within easy sight of Morrisville, the summit of Mount Mansfield was a full 30 degrees warmer at 9 above.

Usually the opposite is true. The higher in elevation you go, the colder it gets.  Typically, it's roughly six or seven degrees colder for every 1,000 feet or so you go up in elevation.

That's why this morning's weather phenomenon is called an "inversion." The normal temperature pattern in the atmosphere was inverted.

So why were things so topsy-turvy in the Great White North this morning?

The short answer: An area of Arctic high pressure that had settled directly overhead in northern New York and northern New England last night.

Cold air is heavier than warm air. When the Arctic air moved in Monday night, it undercut and displaced warmer air, so that the heavy cold air lingered in the valleys while the warm, or at least warm-ish air stayed above.

At night, air in the valleys gets even colder at night without the weak heat from the winter sun, so the inversion intensifies.

That's why it was so cold in the valleys compared to the mountain summits.

The inversion has been in place since early Tuesday morning. In the summer the heat of the sun usually breaks up inversions. The sun heats the ground, the air near the ground warms, starts to rise, causing air up higher to start mixing down toward the valleys, and pretty soon things go back to normal, with colder air up high.

In the winter, the sun's heat is weak, so it doesn't heat the ground much. Plus, snow cover reflects what little heat comes in from the sun back up to space, so that keeps the sun from working well. The inversion holds firm.

This is why inversions are more often than not a winter type thing.

Inversions also trap pollutants. Smoke or particles or anything else get blocked from blowing away by that warm air up above.  The warm air layer acts like a lid. So the pollution sits and gets thicker and thicker, especially in valleys.

You don't think of Vermont as the Capital of Air Pollution, but there was an air pollution alert for the area around Rutland, Vermont last night and this morning. Rutland basically sits in a bowl, surrounded by mountains.

Wood heaters, cars, trucks and whatnot released particulates into the air, which got trapped in Rutland's valley.

Pollution from inversions can be a big wintertime problem in bigger cities in deeper valleys surrounnded by bigger mountains than those in the Northeast.

Salt Lake City, Utah has problems like this frequently in the winter. 

If the air is moist, dense fog will often form in the valleys while it's sunny in the mountains. That happened across northern New England in mid-December during a period of calm weather after a snowstorm.

An inversion usually breaks up when any kind of storm system starts to move air around. Another cold front is approaching the Northeast, and that will start to break up the inversion later Thursday and Friday.

We'll at least temporarily go back to frigid mountaintops and slightly warmer winter valleys.