Air Pollution

Toxicity

Toxin- any substance that is inhaled, ingested, or absorbed and can damage an organism.

Toxicity- a measurement of how biologically harmful a particular toxin is.

Factors that influence toxicity

• Dosage over a period of time

• Number of times of exposure

• Size and age of exposed organism

• Ability of body to detoxify

• Organisms sensitivity (frogs!!!)

• Synergistic effect (more than one toxic substance-effects add up)

Dose response analysis

• Organisms are exposed to toxins at different concentrations until they die- concentration at which they die is recorded

• LD50- the dosage at which 50% of the exposed organisms die

• HIGH LD50 = LOW TOXICITY

• LOW LD50 = High Toxicity

Poison

Any substance that has an LD50 of 50mg or less per Kg of body weight

Two more words

• Acute effect- an effect caused by short exposure to a high level toxin –like a snake bite

• Chronic effect- results from long-term exposure to low levels of toxin

• Example)-long term exposure to lead paint

You do in 2 min

1. What are toxins and toxicity

2. What factors influence toxicity

3. Which is better a high or low LD50 – why

4. When is something considered to be poison?

5. Compare and contrast chronic vs acute effects

Pathogens! – something living that can make us sick

• 5 types

• Viruses

• Bacteria

• Fungi

• Protozoa

• Parasitic worms

• Infection – results when a pathogen invades our bodies

• Disease- a change in health caused by the invasion of a pathogen

Brain eating amoeba

Vectors

• An organism that carries a pathogen and transmits or spreads the pathogen

• Example- Ticks carry Lyme’s Disease- tick bites deer, human, dog- that organism now has Lyme’s disease

Disease outbreak and weather changes

• Risk- how likely it is that a person will become sick after being exposed to a certain pathogen

• Risk Assessment- a study conducted to calculate the risk of a specific pollutant or pathogen

• Risk Management- using strategies to reduce the amount of risk from a pollutant or pathogen

You Do & write too!

• What contemporary topics have we discussed that risk assessments have been conducted on?

• What are three risk management techniques to deal with the environmental effects of using of fossil fuels.

Air Pollution!

• Approximately 14 million metric tons of air pollution are released annually into the atmosphere in the US by human activities.– Worldwide emissions total around 2 billion

metric tons.

• Developed countries have been improving air quality, while air quality in developing world is getting worse.

Natural composition of the atmosphere

• 78% nitrogen

• 21% oxygen

• 1% other – Carbon Dioxide, water vapor, etc.

The terms!• Primary Pollutants - Released directly into the troposphere from a

source, and are also toxic• .Example sulfur dioxide from coal burning power plant

• You do- Identify 3 primary pollutants you have learned about in AP Environmental

Secondary Pollutants

• Secondary Pollutants – Pollutants that form because of chemical reactions often after entering the air and mixing with other environmental components or other types of pollution – Example> Acid rain formed when sulfur

dioxide mixes with water vapor

Point source pollution:

• A specific location from where pollution is released

• Give three examples of a point source location

Non point source pollution

•Pollution that does not have a specific point of release

•Example – cows releasing methane or cars releasing carbon monoxide

2 types of Air Pollution

1. Natural releases from the environment

2. Manmade pollutants

NATURAL SOURCES OF AIR POLLUTION

• Natural Forest Fires - Smoke

• Volcanoes - Ash and Acid components

• Sea Spray – Sulfur from algae

• Bacterial Metabolism - Methane

• Dust

• Pollen

• Mold

Human have always added pollution!

Large scale pollution began with the Industrial Revolution

You do

• Identify and describe one way the industrial revolution significantly increased air pollution?

• Explain the difference between point source and non point source pollution and give an example of each

• Explain the difference between primary and secondary pollutants.

Environmental Protection Agency

• Government agency designed to protect human health and the environment- enforces regulations and laws passed by congress.

Man Made pollution

The dirty ½ dozen/ Criteria pollutants-

• the six pollutants that do the most harm to human health and welfare– Carbon monoxide– Lead (Pb)– Ozone (O3)– Nitrogen dioxide (NO2)– Sulfur dioxide (SO2)– Particulates

How do you know if there is too much

• ppb – parts per billion (small amounts)

• ppm- parts per million (large amounts)

• EPA has mandated “maximum ambient air levels” for the criteria pollutants

Carbon Monoxide

• Released from burning fossil fuels- 60% from vehicles

• Hazardous to humans because it binds to hemoglobin in the blood. Hemoglobin carries oxygen, if it is bound to CO it cannot carry oxygen.

• Hemoglobin has a “higher affinity” for CO than for Oxygen (it binds more easily to CO)

Lead

• Has been around since the Roman empire• Released as a particulate (small particle)

into the air- but then it lands on land and water and enters the food chain.

• Causes neurological disorders in children including mental retardation (& possibly aggression!)

• Used to be from leaded gas – now mostly from smelting (processing metal)

Ozone

• ONLY the ozone from human activity is harmful!• Human created ozone is in the troposphere –

not in the stratosphere where it should be!• Secondary pollutant – formed when nitrogen

oxides, heat, sunlight, and and Volatile organic compounds (voc’s) react.

• Tropospheric ozone is a big part of smog- • Most ozone pollution comes from cars!

Nitrogen Dioxide/ Nitrogen Oxides

• NO2 / NO• Formed when atmospheric nitrogen and

oxygen react when exposed to high temperatures

• Released from combustion engines and industrial combustion (coal burning power plants)

• Can also be a secondary pollutant- and is found in smog and acid rain

Sulfur Dioxide (SO2)

• Colorless gas with horrific odor (smells like rotten eggs mixed with poop)

• Serious respiratory irritant• Released through burning of coal- scrubbers on

coal plants can reduce emissions • Also released through smelting, making pulp (for

paper),fossil fuels and gas appliances• Mixes with water vapor to form acid rain

Particulate matter

• Small particles of solid or liquid

• Light enough to be carried in air

• Humans breath in they irritate respiratory passages (lungs)

• Examples are soot, and sulfate aerosols

You should recognize

• NOx

• Sox

VOC’s

• Volatile organic compounds– Carpet cleaners, dry cleaners, oils, paints,

glues/adhesives

– Of 188 air toxics listed in Clean Air Act, two-thirds are VOC’s.

Progress

• Significant decreases in lead and carbon monoxide because of no leaded gas and engines that burn fuel completely

• However other pollutants are increasing – like Carbon Dioxide and VOC’s

SMOG

London 1952

• Industrial smog led to the death of 10,000 people in London- high levels of smog led to tuburculosis, pneumonia, and bronchitis

• Lead to the Clean Air Act of 1952 in England

Industrial Smog

• Caused by burning of oil/coal

• CO and CO2 and SO2 combine with particulate matter

• Weather can affect smog- air inversions trap fog/pollutants and increase smog

Photochemical Smog

• Formed on hot sunny days in urban areas

• Heat causes ozone formation from NOx compounds

• NOx and VOC’s and Ozone combine to form smog with a brownish color

• LA! (and Athens Greece)

• Athens has laws about which days you can drive – LA does not…..

You Do

• Name and describe the six criteria pollutants

• What is a VOC

• What is Smog- how is it formed

• What progress has been made in remediating air pollution

• What laws were created to protect our air?