APES Chapter 15: Air Pollution

Volatile Organic Compounds

organic compounds that become vapors at typical atmospheric temperatures -hydrocarbons- contain carbon-hydrogen bonds -important role in formation of ozone - some potential to be harmful

What are the two sizes of particulate matter that the EPA classifies? Which is more dangerous and why?

particles smaller than 10 microunits are PM10. Particles of 2.5 microunits and smaller, called PM2.5 are a great concern because they deposit deeply within the respiratory tract and tend to be composed of more toxic substances

Primary air pollutant

polluting compounds that come directly out of the smoke stack, exhaust pipe, or natural emission source

acid deposition

primary pollutants are transformed through a series of reactions into the secondary pollutants nitric acid and sulfuric acid

Secondary air pollutant

primary pollutants that have undergone transformation in the presence of sunlight, water, oxygen, etc.

catalytic converter

reduce the nitrogen oxide and carbon monoxide emissions in vehicles

haze

reduced visibility caused primarily when particulate matter from air pollution scatters light.

particulate matter

solid or liquid particles suspended in air -comes from combustion of wood, animal manure, etc. -natural sources include forest fires, volcanoes, and dust storms -can affect respiratory tract and smaller PM is more toxic

Which pollutants are associated with the formation of smog?

sulfur dioxide, nitrogen oxides, and particulate matter

Which pollutants result from fossil fuel combustion?

sulfur dioxide, nitrogen oxides, carbon monoxide, carbon dioxide, particulate matter, mercury, VOC's

Which pollutants can be harmful to the human respiratory system?

sulfur dioxide, nitrogen oxides, carbon monoxide, particulate matter, ground level ozone

What is the primary cause for the thinning of the ozone layer?

the breakdown of ozone molecules due to a chemical reaction with free chlorine in the atmosphere

ozone layer hole

the depletion caused an area of severely reduces ozone concentrations over most of Antarctica

thermal inversion

the warm inversion layer traps emissions that then accumulate beneath it

What is the main threat that high levels of VOC's pose, even if many are not directly harmful?

they contribute to ground level ozone formation

electrostatic precipitator

use and electrical charge to make particles coalesce so they can be removed

smokestack scrubber

uses a combination of water and air that actually separates and removes particles

What are the main dangers of indoor air pollution in developed countries?

Materials in the home contain substances such as petroleum that give off chemical vapors and VOC's and particulate matter

Which air pollutants are key ingredients in forming photochemical smog?

NO2-->NO+O-->O+O2-->O3 NO+VOC's--> photochemical oxidants

Important facts about lead and mercury

-lead occurs naturally in rocks and soils, anthro fuels, lead based paint in older buildings -mercury found in coal/oil, bioaccumulates -harmful to central nervous system

chlorofluorocarbons

a class of anthropogenic compounds that contribute to the chlorine in the stratosphere

photochemical smog

a class of pollutants formed as a result of sunlight acting on compounds such as nitrogen oxides

sulfur dioxide

a corrosive gas that comes primarily from combustion of fossil fuels such as coal and oil -respiratory irritant, effects plant tissues too -combustion of plants and animals bring SO2 to air- fuels combusted sulfur combines with oxygen or volcanic eruptions or forest fires

asbestos

a long, thin, fibrous silicate mineral with insulating properties

radon

a radioactive gas that occurs naturally from the decay of uranium, exists in granitic and some other rocks and soils

What are the main risks of indoor air pollution in developing countries?

Biomass and coal are burned in open pit fires without the right fuel to air ratio, which causes incomplete combustion. Also, many homes don't have great ventilation systems so carbon monoxide will stay in the home

carbon oxides

CO is a colorless, odorless gas that is formed during incomplete combustion of most matter while CO2 is formed during the complete combustion of most matter

Clean Air Act

Require that the EPA establish standards to control pollutants that are harmful to human health and welfare

Which two gases are largely responsible for acid rain, and what are its main negative effects?

SO2 and NOx are responsible for acid rain, and it causes acidified waters that lower aquatic diversity, releases metals to the surface, and damages buildings

What are the 6 criteria pollutants monitored by the EPA?

Sulfur dioxide, nitrogen oxides, carbon monoxide, particulate matter, lead, and ozone

NAAQS

Through the National Ambient Air Quality Standards the EPA periodically specifies concentration limits for each air pollutant

What is one specific technology that can reduce RM emissions from coal-fired power plants?

baghouse filters can be used to filter out particulates using fabric

What are the main pollutants generated as a result of industrial agriculture?

nitrogen oxides, carbon dioxide

sick building syndrome

because new buildings contain many products made with synthetic materials and glues that may not have fully dried, a significant amount of off gassing occurs

What technology is used to reduce NOx emissions from cars?

catalytic converters

gray smog

dominated by sulfur dioxide and sulfate compounds

What is one specific technology that can reduce sulfur emissions from coal-fired power plants?

fluidized bed combustion

fluidized bed combustion

granulated coal is burned in close proximity to calcium carbonate, reduces sulfur dioxide emissions

tropospheric ozone

harmful to both plants and animals and causes respiratory inflammation such as asthma and emphysema -formed by combination of sunlight, water, oxygen, NOx, VOC's, forms naturally in stratosphere

pollution permits

involve giving firms the legal right to pollute a certain amount

nitrogen oxides

nitrogen oxide is a colorless, odorless gas and nitrogen dioxide is a pungent reddish-brown gas -all combustion leads to formation of some nitrogen oxides -comes from motor vehicles and stationary fossil fuel combustion (anthropogenic) -comes from forest fires, lightning, and microbial action in soil (natural)