Monday, July 29, 2013

Cool in the summer soup

photograph of children sleeping outside in the summer on a fire escape

Extreme heat with humidity levels that are amazonian, as we were reminded in recent weeks - the 111th anniversary of the air-conditioner- is no fun.
We have greater incentive and thus inclination to retreat indoors now.
And of course, when it's the mid-90's (35C) for days in a row, not much else seems very sensible.
In terms of indoor temperature we've arguably never been cooler.
According to Con Ed, in the New York city area alone there are 525.000 central air systems now and increasing by 6% every year and the number of window units is estimated at six million.

Window and wall units are problematic because they are so poorly insulated.
Two years ago a study by the URBAN GREEN COUNCIL found that the average room air-conditioner leaked as much as a six-inch-square hole (15 cm) waste amounting to 1% of city greenhouse gas emissions.
It is good to know that transportation accounts for 33% of carbon emissions in the united states, whereas buildings account for 40%.

While larger cooling systems have become more efficient in recent years, we don't necessarily use them as well as we could.
Federal guidelines and Con Edison advise to keep your home at 78 degrees , the same as municipal buildings.
For every degree a thermostat is set below that, cooling costs increase by 6%.
Extensive research found that, 79 degrees was the upper temperature threshold at which most people could maintain comfort.
Three years ago Con Edison began offering free programable thermostats to residents with central air systems, the thermostats would allow them to adjust temperatures remotely via the internet or mobile phone, so that houses did not have to be chilled when no one was in them.
Only a small fraction of central-air customers are enrolled.
A newer program providing the same service for those with room units has only 1.175 customers signed on.

photograph o kids in the summer cooling off with a fire hydrant

If you do have to go out, you'll find yourself wrapped up in the "summer soup", as William Bryant Logan calls it in his Op Ed piece for the New York Times.
Water vapor is not the only thing in that sopping summer air, it also contains aerosols -both solid and liquid.
They may have condensed from the gasses that emerge from your tailpipe or from a factory chimney, or they may have risen into the air from the ground: tiny particles of silicon, organic matter, threads, starch,spores, bacterial cells, tire rubber.
One of the most common aerosols in the New York City air, thanks in part to the booming restaurant scene, is fat. 
The aerosols and the water-vapor together make summer soup.
A halo of water condenses upon each bit of stuff and this spicy mixture sloshes against your skin, leaving behind a bit of fat and water, while picking up a few of your skin cells for it's own purposes.

Before the industrial age , even at the height of summer, there were not enough aerosols to mix with all the water in the air.
So a small amount of stuff would quickly attract all the extra water, making drops that were heavy enough to fall from the sky as rain.

But nowadays we put so much stuff into the air , that mot every tiny vapor puff has an aerosol partner, making for a lot of little wet airborne parcels, each to small and to light to fall.
There is on average 5% more water in the air now than there was during World War II.

This is the summer soup, it can stay put for a long time.
It envelops us with it's miscellany of flavors , solids and liquids.
It is reluctant to rain.
Today it just doesn't rain, it pours.
We get cloudbursts , the soup hangs around us for days.
Then suddenly there's a change, a cold front of converging air, or hot rising air, pushes the soup up higher into the atmosphere.
There it get's colder and the rest of it's vapor condenses.
One drop falls into another, pick's it up and slams into another.

Finally, big , thick drops come down.

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