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March 12, 2013

air pollution blog series

Air Pollution Blog Series: Part One

This winter, the winter of 2012-2013, has been marked by some intense inversions in Utah (what is an inversion link).  Inversions are an interesting occurrence because they trap much of the pollution that we generate locally in the lower atmosphere.  As a result the otherwise invisible emissions of our activities become partially visible as their density increases and as they react amongst themselves and other atmospheric gases to produce secondary pollutants day-after-day.  
Photo courtesy  http://www.cleanair.utah.gov/images/photos/InversionStateCapitol.jpg

I began to wonder a few weeks ago where all of this air pollution comes from.  What are the major sources? What is being done to curb it?  How is air pollution measured and monitored?  What are some issues surrounding air pollution in Utah?  I don’t plan on being able to answer all of these questions at hand and so I will explore these questions in a series of blogs over the coming weeks.

In Utah the government agency that monitors air pollution is the Division of Air Quality (DAQ) which is a subunit of the Division of Environmental Quality.  The DAQ reports to the Environmental Protection Agency (EPA).  They have various monitoring stations throughout the state of Utah that measure the amount of, PM10, PM2.5, O3, CO, SO2, NO2 and Pb, in the air. 
I consulted the EPA’s website to find out what the health effects and major producers of each category of air pollutant are (6 common air pollutants EPA link). 

PM10 and PM2.5 refer to particulate matter of 10 micrometers and 2.5 micrometers or less, respectively.  Particulate matter is particularly damaging to the lungs and heart.  It can be dust, particles in smoke, metals, organic molecules, and gases from combustion and industry that react in the air.  

Particulate matter was one of the catalysts that began a closer monitoring of air quality in industrialized areas.  A classic study in 1952 was done reporting the number of deaths and sulfoxide levels (sulfoxides being a component of particulate matter) during an intense London smog.  It was found that there was a very strong correlation between deaths and particulate matter (the number of deaths was as high as 4 times the normal average for a given day!  It rose from around 200 deaths per day to over 800 deaths per day in the week and a half of the smog).  This study was soon followed by other studies at Harvard and many other institutions that definitively proved a correlation between particulate air pollution and number of deaths.  With this evidence, air pollution monitoring and regulation of particulate matter emissions became law in the USA.  

O3 or ozone is not a pollutant when in the higher atmosphere protecting us from UV radiation, but at ground level it can cause respiratory irritation and worsen respiratory diseases.  Prolonged exposure can scar the lungs.  Ground level ozone is created by sunlight catalyzed chemical reactions between nitrogen oxides and volatile organic compounds mainly emitted from vehicles and industries.

CO or carbon monoxide is a product of partial combustion when there is insufficient oxygen in the reaction between oxygen and hydrocarbons.  CO can cause death because our blood cells preferentially bind it over oxygen when we breathe thus causing oxygen deprivation to vital organs.

SO2 or sulfur dioxide also wreaks havoc on the respiratory and its major emission sources “are from fossil fuel combustion at power plants (73%) and other industrial facilities (20%).  Smaller sources of SO2 emissions include industrial processes such as extracting metal from ore, and the burning of high sulfur containing fuels by locomotives, large ships, and non-road equipment.”  (Source cited: http://www.epa.gov/air/sulfurdioxide/)

NO2 or nitrogen dioxide is produced mainly by vehicle emissions, small engines, and power plants.  It is also implicated in respiratory ailments.  Nitrogen oxides react in sunlight with other chemicals to produce ozone as a secondary pollutant. 

Pb or lead “Once taken into the body, lead distributes throughout the body in the blood and is accumulated in the bones.  Depending on the level of exposure, lead can adversely affect the nervous system, kidney function, immune system, reproductive and developmental systems and the cardiovascular system.  Lead exposure also affects the oxygen carrying capacity of the blood.  The lead effects most commonly encountered in current populations are neurological effects in children and cardiovascular effects (e.g., high blood pressure and heart disease) in adults.  Infants and young children are especially sensitive to even low levels of lead, which may contribute to behavioral problems, learning deficits and lowered IQ.” (Source cited: http://www.epa.gov/airquality/lead/health.html) “Major sources of lead emissions to the air today are ore and metals processing and piston-engine aircraft operating on leaded aviation gasoline.  The highest air concentrations of lead are usually found near lead smelters.  Other stationary sources are waste incinerators, utilities, and lead-acid battery manufacturers.” (Source cited: http://www.epa.gov/airquality/lead/)
Thankfully, because of regulation by the EPA, many major sources of lead have been eliminated--such as from leaded gasoline.

Most of the pollutants monitored seem to be related to chemicals and particulates that cause respiratory complications.  Why other chemicals that might have adverse developmental, carcinogenic or neurotoxic effects are not regularly monitored in the air might be a question to research later, but for now I wonder who does the polluting and in what proportions?

File:Lake Side Power Plant.jpg 
Photo courtesy http://en.wikipedia.org/wiki/File:Lake_Side_Power_Plant.jpg

Driving through Lindon/Orem I see the vapor plumes of the natural gas Lake Side Power Station and from N. Salt Lake I can see the refineries with tall fires coming out of the stacks.  These seem like prime sources of pollution to me but the Division of Air Quality website gives this breakdown for total pollution in Utah: 57% is from vehicles, 32% is from “area sources” (houses, small businesses, buildings, etc.), and 11% is from “industry point sources.” (Sited source: DAQ pollution breakdown graphic)  This would ironically imply that as I am driving the roads criticizing industries for being the major polluters that I, unknowingly, am actually part of the largest polluting demographic in Utah: vehicles.

How the DAQ's breakdown of 57%, 32%, 11% is arrived at I couldn't find on their website (quantified data without the supporting methodology applied to obtain it is problematic).  As such, it should be met skeptically when considering its accuracy, but it isn't that surprising that cars, residencies and small businesses are the major contributors to air pollution considering how many vehicles are on the road on any given day in Utah and that the population of Utah rose by 530,716 people from 2000-2010 according to the US Census (2,233,169 (2000)--2,763,885 (2010)).

As always, however, there are some confounding factors and some problematic questions I'll have to ask as a result of my research into the causes of air pollution in Utah and these I will address in the next blog of this series. 

-Seth Commichaux

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