What are the 6 air pollutants that have set National Ambient Air Quality Standards?
Which 2 are the most widespread health threats?
Particles and ground-level ozone are the most widespread health risks
What is particle pollution?
What size particles have the highest potential for causing health problems?
Particle pollution is a mixture of small particles [ injury.
Describe:
in terms of where they are found and what size they are
Inhalable coarse particles:
Fine particles
What is ground-level ozone?
Ozone in the trophosphere that is harmful [as opposed to ozone in the stratosphere which protects life on earth from the suns rays]
How does ground-level ozone form?
What is the seasonal preference?
Forms by a chemical reaction between nitrogen oxides and volatile organic compound in the presence of HEAT and SUNLIGHT
-motor vehicle exhaust, industrial emission, gasoline vapor, chemical solvents
What is the primary constituent of ground-level ozone?
How does this effect our health?
Smog is the major constituent.
03 produces free radicals that injure epithelial cell lining of the respiratory tract and type 1 alveolar cells causing:
What are the major sources of CO?
What is the seasonal preference for high levels of CO in outdoor air? Why?
Colder months because there are “inversion conditions” where air pollution gets trapped near the ground beneath a layer of warm air
How much greater is the Hb affinity for CO over O2?
What levels cause systemic hypoxia?
What levels can cause unconsciousness and death?
200x affinity for CO
20-30% CO –> systemic hypoxia
60-70% CO –> unconsciousness and death
What is the major effect of chronic CO poisoning [low levels but persistent exposure]?
Widespread hypoxic damage to the CNS
What are the major effects of acute CO poisioning [suicide, accidental exposure]?
Sulfur is present in which materials?
When are sulfur oxides formed?
Once sulfur oxide is released into the air, what 2 things can it form?
It is in crude oil, coal and ore.
SO2 is formed when fuel containing sulfur is burned [gas extraction from oil, metal extraction from ore]
-electric utilities, petroleum refinery, cement factory, metal processing plants, large ships
S02 can dissolve with:
Both sulfuric acid and sulfate particles can cause respiratory problems esp in people with asthma
What is the normal appearance of Nitrogen oxides?
How does the appearance differ when it is NO2?
Nitrogen oxides are highly reactive gases that are ODORLESS and COLORLESS.
However, nitrogen dioxide along with particulates are reddish-brown layer over urban areas
When do nitrogen oxides form?
What are the man made sources?
When fuel is burned at high temperatures [as in combustion process].
-cars, electric utilities, industrial, commercial, residential sources of burn fuels
What are the 4 negative effects of nitrogen oxides?
What were the main sources of lead emissions historically?
What has changed?
Historically:
Now metal processing is the major source over cars because the phasing out of leaded gasoline
What is the most widespread source of lead today for US children?
flaking lead paint from old buildings and soil contamination
Why are children at greater risk of lead toxicity?
When lead is absorbed from food, where does it distribute?
What is the effect of lead on pregnancy?
Lead competes with calcium and binds phosphate in the bones.
When a woman is pregnant or lactating, this is a calcium stress and Lead is released into the blood where it can expose the fetus/infant.
What enzymes are inhibited by lead?
What is the clinical result of inhibiting these enzymes?
What are the indicators of lead toxicity in the blood?
When ferrochelatase is inhibited there will be elevated blood:
Lead affects every organ system, but what are the most notable?
What is the most useful screening and diagnostic test for recent or ongoing lead exposure?
venous blood lead concentration {BLC}