Outdoor Exposures Flashcards
Who determines the Air Quality Index (AQI)?
the EPA, AQI is a color-coded and numeric scale (6 levels), Green (0) - Maroon (500)
What are some major sources of air pollution?
Major sources: power plants, refineries, transportation
Smaller sources: nail salons, dry cleaners, auto body shops
Classification of particulate matter(PM): PM10
All particles ≤ 10 microns. Anything bigger usu. not deposited in lungs
Classification of particulate matter(PM): PM2.5
- fine fraction particles
- Directly emitted from combustion sources and formed secondarily from gaseous precursors of sulfur dioxide, nitrogen oxides, or organic compounds
- Remains in atmosphere days to weeks and travels through atmosphere hundreds and thousands of km.
- Main cause of reduced visibility (haze) in the U.S.
Classification of particulate matter(PM): PM10-2.5
- coarse fraction particles
- Tend to deposit to the earth w/in mins to hrs and w/in tens of km from emission source
Classification of particulate matter(PM): Ultrafine
- all particles < 0.1 microns
- May leave lung and travel thru blood to other organs, including heart
Define acid rain
Any form of wet precipitation with ph <5.6
What causes acid rain and what are the effects of it?
- Caused by fossil fuel emissions: S and NOs combine w/ H20 in the atmosphere
- When the environment cannot neutralize the acid deposited → damage! Such as accelerating the decay of buildings, changing aquatic ecosystems, and loss of nutrients in forest soils
Define smog
- Combination of words smoke and fog
- Mixture of air pollutants including gases and fine particles often seen as a brownish-yellow or grayish-white haze in the air
How does smog form and from what?
- Formed in Earth’s lower atmosphere when pollutants from cars, refineries, power plants, etc. react chemically in the presence of sunlight
- Components: Ground level ozone, Nitrogen oxides, Volatile organic compounds (VOCs), Sulfur dioxide and Particulate matter
What are the 6 criteria pollutants?
Pollutants the Clean Air Act requires the EPA to set standards for:
- Ground level ozone
- Nitrogen oxides
- Polycyclic aromatic hydrocarbons (PAH)
- Benzene
- Carbon Monoxide
- Particulate Matter (particles of soot, dust, or other matter including small droplets of liquids)
How is ground level ozone created?
- Not emitted directly into the air but created by chemical reactions between oxides (NOx) and Volatile Organic Compounds (VOCs) in the presence of sunlight (i.e. ozone is a secondary pollutant)
How does carbon monoxide exposure impact health?
RBCs can pick up CO quicker than O2. If there is a lot of CO around, they may replace the oxygen in the blood with CO → tissue necrosis→ death
What symptoms are associated with carbon monoxide poisoning?
HA, Dizziness, Weakness, N/V, Chest pain, Confusion
HIGH LEVELS: LOC and death
What is the main cause of haze?
PM2.5 = fine fraction particles
What is the primary cause of acid rain?
Sulfur Dioxide (colorless gas, smells like burnt matches)
What are CFCs?
Chlorofluorcarbons = compound consisting of chlorine, fluorine, and carbon.
Where are CFCs commonly used in and why are we concerned?
Commonly used in: Refrigerants, Solvents, Foam blowing agents
Concern: Very stable in the atmosphere, moves to the stratosphere and is broken down by strong UV light which releases the chlorine atoms that break down the ozone layer
What is being used to replace CFCs?
HCFC = Hydrochlorofluorocarbons
- EPA efforts to reduce the amount of ODS (Ozone Depleting Substances) produced or imported into the U.S.
- Contains chlorine and thus depletes the ozone but less so than CFCs
Notable characteristic organochlorine pesticides and what are some examples?
Commonly used in the past but many have been removed from the market because of their health and environmental effects and their persistence
ex: DDT, Chlordane, Dieldrin, Heptachlor
Notable characteristics of organophosphates pesticides?
- Developed during the early 19th century but main effects were realized in 1930s; used in WWII as nerve agents
- Popular after ban of organochlorines in the 1970s
- acetylcholinesterase inhibitor
- Higher toxicity than carbamates
Notable characteristics of carbamate pesticides?
- Salts or esters or carbamic acid
- acetylcholinesterase inhibitor
What is the health concern regarding fertilizers?
Nitrate alters the iron in hemoglobin from the ferrous to the ferric state, which forms methemoglobin (abN hemoglobin) → blood loses its ability to carry oxygen to tissues.
What are the 2 classes of acetylcholinesterase inhibitors that are pesticides?
Organophosphates and Carbamates
