At what height can I breathe right?

At what height can I breathe right?

By: Veronica Pineda

In 1952 the heart of Industrial Revolution experienced what was deemed the “Killer Smog.” Over 4,000 people suffocated in London from the terrible pollution of burning coal and releasing smoke vicariously into the air.

This was one of the gravest environmental repercussions of London’s rapid Urbanization that led to air quality regulation. But as the human population is expected to grow to 9 billion by 2050 with 70 percent living in urban areas more information on how humans contribute to air quality is needed to prevent disaster like that of London.

Currently, research is being done on this at the University of Utah by graduate research assistant Lacey Holland. Her research is monitoring the effects of urbanization on air quality from over 1,000 metropolitan locations around the world.

Her observations are based on records from a weather balloon called “Radiosonds” that are sent up twice a day to assess a vertical profile of the atmosphere.

By finding out the stability in the air and how the wind changes with height, Holland can determine an average height of where the air stops being so turbulent. The boundary between this height and our surface is called the “mixing height.”


“The big question that I’m trying to answer is do people effect the mixing height and if so does it have an effect on air quality,” said Holland.

The Earth's atmosphere naturally contains “greenhouse gases” such as, water vapor, carbon dioxide, methane, ozone, and nitrous oxide. They make the planet suitable for life as we know it.

Trees, mountains, rivers and other natural obstructions also create turbulence in the air.

But with Urbanization, our construction and emissions have produced a new dynamic variable to air quality.

The emissions from cars, refineries, and power plants mix together and collide against our buildings reversing their direction of flow and continuing their chaotic dance through the streets and alleys.

This turbulent flow of all the pollutants around people formed a lid that restricts any of those pollutants of ventilating out into the free atmosphere.

Depending on the geographical and atmospheric variables of that city, the mixing height layer ascends and descends anywhere between 100 meters to 1,00 meters such as a balloon of condensed and transforming contaminants.

“ Whenever the mixing height is low to the ground that means that there is a higher concentration of these chemicals and pollutants,” said Holland. “And whenever it’s up high, there is a bigger volume to be spread over so the concentration aren’t so high.”

Just imagine breathing in air in which all the contaminants have been crammed into one-tenth of the space it usually inhabits. Many of the gases and particles in the air are known to have adverse effects on people’s respiratory system.

Exposure to high nitrogen dioxide levels can contribute to the development of acute or chronic bronchitis, according to the Environmental Protection Agency (EPA).

According to the EPA, in the case of the London’s “Killer Smog,” it was high concentrations of sulfur dioxide that come from fossil fuel combustion at power plant’s industrial processes such as, extracting metal from ore, and the burning of high sulfur containing fuels by locomotives, large ships, and non-road equipment, according to the EPA.

The smog gave humans and animals difficulty breathing and induced the vomiting of phlegm.

Temperature has also shown to be a major variable affecting the mixing height. The change to cooler air lowers the mixing height.

In reference to Salt Lake City, the biggest impact is going to be in the winter because the mixing height becomes so low in the valley said Holland.

The mixing height is usually at its highest during the day and at its lowest at night, she said.

According to the EPA, Urbanization has also created a “heat island effect” in which the city becomes 0-3 degrees Celsius warmer than its surroundings.

“Initially I thought mixing heights would get bigger. SO if it gets bigger that means pollutants are spread out with more volume,” Holland said.

But her observations have proven otherwise.

In Beijing, the mixing height is increasing during the day and the night. In New Delhi, the mixing height is increasing at night and decreasing during the day. Mexico City’s mixing height is slightly decreasing during the day and the night.

According to a report by The Daily Finance, these cities are considered both the most developed cities in the world and also the ones with the worst air quality.

“What I think is happening is that in some cities it can be like urban heat island stuff, but for other cities it could be depending on some pollutants that they produce,” said Holland.

Different types of particles have different impacts on climate. Black carbon warms the climate while sulfates and nitrates cool the climate, according to the EPA.

The way these gases react with sunlight and with other pollutants is still in question to how it’s affecting the mixing height. But Holland’s research is mostly observational and the data has revealed how urbanization is causing wild fluctuations in mixing height.

Holland hopes that her research will influence individual awareness of how people contribute to air quality.

“I think that the main thing that will come out of it will be the effects people have on their surroundings,” she said.

During the past 20 years, about three-quarters of human-made carbon dioxide emissions were from burning fossil fuels according to U.S. Energy Information Administration.

It’s the inefficient combustion from our cars, our trends in consumption, and our use of energy that is the adding to the concentration of gases in our air.

It took killer smog that only lasted four days to directly influence the implementation of the Clean Air Act.  Despite regulation efforts, similar smog 10 years later killed approximately 100 Londoners.

What will it take for each city to take sustainable initiatives as populations grow?

“It will be interesting to see as people move to a place so quickly what impact they have on environment,” said Holland. 

Atmospheric Boundary Layer

Light pollution and the planetary boundary layer over Berlin