APES Unit 7 Quiz Flashcards
Why do we care about air pollution?
Air pollution kills an estimated 7 million people each year (60,000 US)
This is often premature death via stroke, respiratory disease, lung cancer, and heart attacks
Some studies have suggested that air pollution can mimic effects of regular cigarette smoking in areas where it is severe (in terms of lung health)
Creates chronic diseases
Premature death - people who are dying before they should be dying (in this case because of air pollution)
Primary pollutants
directly emitted by natural or anthropogenic sources
Secondary pollutants
are released when primary pollutants react in the atmosphere to form them
Creates otherwise dangerous and harmful pollutants which we don’t emit
Eg. we don’t emit ozone so ozone is a secondary pollutant
Clean Air Act of 1970- Thresholds for 6 Air Pollutants
Sets a threshold for these pollutants (sets a maximum amount allowed in the air)
Knowing sources is important - sulfur is a byproduct from burning coal
10 fold safety factor factored in
Sources:
Sulfur compounds → primarily coal
Nitrous oxides → all FF combustion
Carbon monoxide → combustion byproduct (incomplete combustion - instead of creating CO2 it creates CO)
PM (particulate matter ~ like ash any particle thats extremely small) → any combustion, especially biomass and coal
Lead → factories or waste incineration (we got rid of led in fuel so it’s not as significant anymore)
Ozone (secondary pollutant) → VOCs react with nitrous oxide
Through the Clean Air Act, the Environmental Protection Agency (EPA) regulated the use of lead, particularly in fuels, which dramatically decreased the amount of lead in the atmosphere
1970s- new vehicles needed catalytic converters that could not take lead (phased out the use of led in gasoline)
1990s- all lead gasoline banned in US for vehicles- still used in some other equipment that is older (eg. tractors)
All Countries to date have banned leaded gasoline (Algeria in 2021 was last one)
Lead is so bad as it’s a neurotoxin that affects your brain, most common place is paint that has lead in it (problems as children will eat little pieces of paint coming off the walls) (and lead bullets can get eaten by animal that were shot by them killing them )
Up until a few years ago many nations were using lead
Even a small amount of lead is very dangerous
nitrogen oxide emissions
The combustion of fossil fuels releases nitrogen oxides into the atmosphere. They lead to the production of ozone, formation of photochemical smog, and convert to nitric acid in the atmosphere, causing acid rain. Other pollutants produced by fossil fuel combustion include carbon monoxide, hydrocarbons, and particulate matter.
NOx- Nitrous oxides- the x refers to the many different compounds that fall into this category
NO and NO2 are most common nitrous oxides that are formed due to the combustion of fossil fuels, mostly in vehicles and power plants
Nitrous oxides can interact with other particles (like VOCs) in the atmosphere to form ozone, which is an air pollutant in the troposphere and can lead to smog
Nitrous oxides can interact with water vapor in the air to produce nitric acid, one potential culprit of acid rain
Ways to reduce nitrogen oxide emissions:
Cleaner fuels
Maintain vehicle maintenance
Optimize combustion process
sulfur oxide emissions
Air quality can be affected through the release of sulfur dioxide during the burning of fossil fuels, mainly diesel fuels.
Sulfur dioxides (mostly SO2 but there are many) are air pollutants released in industrial settings and when fossil fuels (coal) are burned for power generation.
Sulfur dioxides, like most air pollutants, are responsible for respiratory issues and lead to potential asthma, especially in elderly people and children
Gaseous SO2 is harmful to plants and can inhibit growth
SO2 can interact with water vapor in the troposphere to create sulfuric acid, which leads to acid rain
photochemical smog
Ozone, PM 2.5, and other pollutants can cause a visible haze referred to as smog
Post industrial revolution with very little environmental regulations
Windows covered in black soot, made it hard to live there
Power plants, burning fossil fuels/wood cause this
Wildfire produces it the most (like when the sky turned orange → this is very dangerous)
Smaller the particles are = more hazardous they are
PM 2.5 is very small and it is the most dangerous because you can inhale it deep in your lungs, if the particle was like PM 10 it is less likely to do this but it is still dangerous
“Normal” Troposphere Ozone Formation
rimary cause of the smog is ozone when it is in the troposphere
Naturally occurring, considered an air pollutant in the troposphere
Hole has been a huge problem
Tropospheric ozone commonly forms in areas with significant combustion of FF-
Nitrogen dioxide formed from combustion is broken down into NO and O by sunlight and heat. The ‘free’ O is able to find O2 molecules and create O3 (ozone)
Ozone forms during the morning
Ozone decays pretty quickly back into o2 and No
This leads to a buildup of ozone by day but relief later in the day
During the day ozone formation builds up but then decays during the night
Prevents ozone from building up too much in the troposphere
VOCs and Ozone
VOCs can accelerate ozone production by giving an oxygen to NO so it doesn’t ‘steal’ one from ozone and allow ozone to break down as quickly
I think VOCs can also react with certain chemicals to create ozone but the organic chemistry here is far above my head
Remember Sunlight + NOX + VOCs= OZONE!!
When you add VOCs it disrupts the cycle as it quickens the process as it prevents ozones from breaking up
In summary = VOCs create a lot of tropospheric ozone
Formula for bad smog
What are VOCs, Anyway?
Volatile Organic Compounds- can come from natural sources such as trees, but typically emitted from the following:
Building/Construction Materials, including paint, adhesives, varnishes
Cleaning Supplies
Cosmetics
Gasoline
Pesticides
Frires, fast food restaurants
Manufacturing chemicals and solvents
Smoke/high heat cooking with oil
Best example - nail polish and nail polish remover, all VOCs chemicals which are vaporizing easily
Where is smog a major issue and how to reduce it
Smog is an issue in cities, especially in the summer and in areas that receive a lot of sunlight and hot temperatures.
Essentially, smog is worse during daylight and better at night.
Smog irritates respiratory symptoms and can have negative health effects, including buildup of tar on lungs if chronically exposed to pollutants like PM2.5
Trap in pollutants
Review: Urban Heat Island Effect
More urban areas with lots of concrete is hotter than more suburban and rural areas
Happens due to black roads and concrete absorbing a lot of heat, no trees which give off shade and reflect, evapotranspiration
Lack of trees = lack of evapotranspiration = lack of cooling effect = hot!
Thermal Inversion
“Normal” periods are helpful because warm air near the surface that contains all the pollutants rises and brings pollutants with it
Hot air rises and then gets cooler and cooler as you go up - good as pollutants are contained in the warm air going up meaning we aren’t breathing it in
Eg. when you are on a plane and you get further up the temp significantly drops
Inversions prevent this from happening by ‘sealing’ surface level air with pollutants
Cool -> warm-> cooler
Warmer air forms above cool air
Two reasons why it occurs - anthropogenic, natural
Hot air rises, during the night the air below gets cooler, this means that cooler air is trapped by the warm air above
Cloud layers are really low, cold air blows under, shorter
There are both natural and anthropogenic causes of thermal inversion. Let’s hypothesize what they both are……
What is acidity
Acidity is a measure of hydrogen ions in an aqueous solution
Natural Sources of Air Pollutants
Volcanoes- SO2, PM, NOX, CO
Lightning- Atmospheric N2 into NOX
Fires- CO, NOX, PM
Plants/Trees- VOCs, CO2
Animals- Respiration generates CO2
Natural PM- Forest Fires, Pollen, Dust
Decomposition- Releases CO2 or CH4 (why dead things smell, b/c methane, VOCs produced as well)
PM 10 and PM 2.5
Smaller the particle the worse it is
Small particles - fire ash from combustion
Smaller particles travel deeper into lungs
Smaller particles generally generate combustion generated, while larger ones are more likely to be dust, pollen, mold spores, etc.
Indoor Air Pollutants
Can build up inside in ways that outside pollutants can’t
PM
Asbestos
CO
VOCs
Radon
Mold
Lead
Particulate Matter and Mold
C
Carbon Monoxide
Carbon Monoxide- CO- product of incomplete combustion
Not enough oxygen for combustion reaction to happen the way it should, so it produces CO
ANY combustion can produce CO- which is extremely deadly- CO outside is quickly diluted by air and does not normally concentrate (can be caused by house fires, any combustion, etc.)
Outside it is not a concern, but inside it can build up to high concentrations
Indoors, CO can become deadly- causing loss of consciousness within minutes and death shortly after
A PROBLEM - in indoor spaces without good ventilation
Colorless, odorless (which means that you don’t know if it is there) - CO detectors are a must in homes!
Any source of fossil fuels in your home can produce CO
CO binds to hemoglobin causing asphyxiation
100,000 ER visits per year in USA
Fires are a common source of CO poisoning, but automobiles, generators, fireplaces, and other activities can also lead to high CO levels
Lead
Lead is a neurotoxin, affecting the brain
Most of our homes built when lead was common, but is not used in paint today
You can breathe in lead, concern with alzheimers and lead
Lead from paint is most common source, but certain windows and some soil is contaminated
Lead poisoning can occur via ingestion but also via inhalation of small particles (paint chip)
Neurodegenerative decline can result over time with chronic exposure (especially as children), but lead can also kill someone in a single dose
VOCs
Cleaning supplies may be among the most significant indoor sources in residential homes- cooking is another large source (use vents when cooking or open windows)
Radon
Naturally occurring: Colorless, odorless, radioactive gas, you don’t notice it
Can infiltrate through foundation of a home and can build up overtime, through cracks in the foundation
You can possibly ventilate radon
Long term, chronic thing, builds up and you get sick
Found in rocks and dirt, only dangerous when it builds in home and is breathed in over a long period
Second leading cause of lung cancer in US
Radon decays in lungs into particles that can damage lung tissue
Typically a concern on lower levels of homes
Can test for radon with a 24 hour test
Asbestos
Mineral- typically used in insulation for homes (not so much anymore, but many older homes still have asbestos). Also used as fireproofing as it is very heat resistant
We mine for it and place it in attics
Normally, asbestos stays put- and poses no risk- but disturbing it can release particles into air that can be inhaled. In nature, it occurs in low concentrations but in homes the concentration can be much higher
Glass shards that can go airboard easily getting glass into the air
Smoking plus repeated asbestos exposure can lead to greatest risk of a rare and aggressive form of lung cancer, causes mesothelioma, usually doesn’t show up until about 30-40 years after asbestos exposure
Most exposure comes from destroying a home or playing in installation
reducing air pollution: the obvious
Reducing air pollutants isn’t hard…..
The Clean Air Act of 1970 had a huge impact! Legislation
Others are simple- switching to other types of insulation, venting homes and workplaces, having detectors for unsafe compounds can all help improve indoor air quality.
Outdoor air quality can be improved by transitioning away from FF and requiring technology that improves emissions- like scrubbers and catalytic converters!
reducing air pollution: technology and innovation - catalytic converters
Emissions from vehicle travel through catalytic converter- between engine and exhaust
Chemical reactions (redox) occur to chemically change VOCs, NOXs and CO into less harmful substances (like nitrogen gas, water, co2)
Harmful to less harmful
It is illegal to remove a catalytic converter from a vehicle in NY unless replacing it- although there is an issue with theft because they contain valuable metals and are often not particularly secure
Made with rare minerals causing people to melt them in order to sell on the black market causing people to steal them
Part of federal and state gov push to reduce air pollution
reducing air pollution: technology and innovation - vapor recovery nozzles
Gasoline contains VOCs and is highly flammable- gas stations typically stink of gas
Gasoline is very volatile meaning that it evaporates quickly
Captures the vapor from gasoline from going into the air and puts it back into the gas tank
Prevents VOCs emission and saves little bits of gas
Gas evaporates off the tank of the car being filled (it ‘boils’ or evaporates at a low temperature- hence volatile)
Vapor recovery nozzles capture those vapors and return them back to the gas tank- where it is pressurized and cooler-
Some of these vapors recondense into gasoline
reducing air pollution: technology and innovation - scrubbers
These are essentially filters (think of a water filter) that capture contaminants from factories or power plants before gas is let out
Scrubbers aim to remove PM, acidic gases (by neutralizing them), VOCs
They are NOT effective at removing NOx or CO2 (CO2 is not really an air pollutant)
Different from catalytic converters as they captures different things
LOOK AT INFO ABOUT DIFFERENT TYPES GO BACK TO DOCUMENT
Acid Rain
SOx and NOx interact with water and oxygen to form acids
H+ ions dissociate in water, and H+ is acid (Power of Hydrogen)
H+ ions fall with rain, making soil and streams, rivers, and lakes more acidic
Acid is pretty much hydrogen
As there is water in the atmosphere and with the oxides in the air it combines with the water to create acidity
HNO3
H+ & NO3 -
Acid can rob plants from nutrients as the acid will attach to the roots instead of the nutrients
Average PH of rainwater now is 5.5
