Air Pollution Flashcards
NAAQS has standards for 6 “criteria pollutants”
- Primary standards
* Secondary standards
Clean Air Act
EPA establishes National Ambient Air Quality Standard (NAAQS)
Primary standards for Clean Air Act
Set to levels to protect human health
Secondary standards for Clean Air Act
Set to protect environmental property damage
Regulated air pollutants
- Carbon Monoxide (CO)
- Nitrogen Oxides
- Ozone
- Sulfur Oxides (SOx)
- Particulate Matter (PM)
- Lead
Carbon Monoxide (CO) (primary pollutant) produced by…
incomplete combustion of carbon
Major source of Carbon Monoxide
Motor vehicle exhausts
Health effects on humans of Carbon Monoxide
- binds to hemoglobin
- forming carboxyhemoglobin (COHb)
- reduces the oxygen carrying capacity of blood
CO sources
1) on-road vehicles: 56%
2) non-road vehicles and engines: 22%
3) miscellaneous: 12%
4) fuel combustion: 6%
5) industrial processes: 4%
How many Oxides of Nitrogen are there?
7
2 important air pollutants of nitrogen oxides (primary pollutant)
1) NO: nitric oxide
2) NO2: nitrogen dioxide
Health effects of NO
- NO2 irritates lungs
* promotes respiratory infections
Environmental effects of NO
- Acid deposition (rain)
* Formation of photochemical smog
Acid rain
- NO2 results in the formation of nitric acid
* causing acidification of lakes (drops pH of water) & eutrophication
Formation of photochemical smog
Sunlight + NOx + hydrocarbons –> photochemical smog (e.g ozone)
NO sources
1) motor vehicles: 55%
2) utilities: 22%
3) industrial/ commercial/ residential: 22%
4) all other: 1%
Ozone know as…
“Secondary pollutant”
Tropospheric (ground level ozone)
- air pollutant
* harmful to humans/ vegetation
Stratospheric ozone
- beneficial to humans
* protection from harmful UV radiation
Primary pollutant
Directly emitted into the atmosphere
Secondary pollutant
Created by reactants in the atmosphere
Health effects of ozone
- increased incidents of respiratory distress
* symptoms: chest pain & coughing
Environmental effects of ozone
- reduction in agricultural yields, forest yields
* increased plant susceptibility to disease, pests etc.
Sulfur Oxides (SOx)
- all fossil fuels contain sulfur
* during combustion, SO2 is released
Health effects of sulfuric oxides
Temporary breathing impairment
Environmental effects of sulfuric oxides
Acid deposition: SOx reacts with H2O to form sulfuric acid
Sources of sulfuric oxides
~86% fossil fuel combustion: mostly coal-fired power plants
~5% highway vehicles
Particulate Matter (PM)
- consists of small particles & liquid droplets
- also called “aerosols”
- may include: soil, smoke, dust, acids, organic chemicals
2 classifications of PM
1) PM 10
2) PM 2.5
PM 10
- course particles
* 2.5 μm- 10 μm in diameter
PM 2.5
- fine particles
* 2.5μm and smaller
Health effects of particulate matter
- potential for heart & lung disease
* primarily 2.5
Environmental effects of particulate matter
- decreased visibility
* damage to buildings e.g paint
Lead
- historically motor vehicles were important
* as lead gasoline was phased out, emissions have decreased
Lead health effects
- accumulates in the blood, bones & soft tissues
- adversely affects the kidneys, liver & other organs
- may cause neurological impairments e.g seizures, mental retardation & behavioral disorders
- may be a factor in high BP & heart disease
