Environmental Science Chapter 19

Describe the current state of ozone pollution in San Diego, including it spatial distribution, and how that spatial distribution co-occurs with the distribution of different ethnicities.

San Diego in a non-attainment area for ozone pollution (meaning it does not meet current EPA standards for human health). It is the 20th most polluted urban area in the United States for ozone. Spatially, it is lowest near the coast and highest inland- likely due to onshore flow from the coastal winds. Despite controlling for factors like income, minority ethnicities tend to suffer higher cancer rates from air pollution. This may be because communities are clustered near areas where point source pollution is high, like near industry, freeways, etc.

Photochemical Smog

brownish/orange haze formed by chemical reactions involving sunlight, nitrogen oxide, and hydrocarbons. A temperature inversion (higher air is warmer than air close to the ground) may temporarily halt air circulation and will cause this smog to sit at ground level and be breathed by humans for long periods of time. (LA Basin). This inversion occurs to cities that are in valleys, on leeward sides of mountains, and along the coast. This smog reduces visibility, causes respiratory illnesses, and can damage plants.

Particulates

consists of thousands of different solid and liquid particles suspended in the atmosphere. Solid particulate matter is generally referred to as dust, whereas liquid suspensions are commonly called mists includes a variety of pollutants such as soil particles, soot, lead, asbestos, sea salt and sulfuric acid droplets

Hydrocarbons

diverse group of organic compounds that contain only hydrogen and carbon, the simplest is methane (CH4) which is a natural gas. Ozone: a pale blue gas that is both pollutant in the lower atmosphere (troposphere) and an essential component that screens out UV radiation in the upper atmosphere (stratosphere

Stratosphere

extends 12-50 km above earths surface, oxygen reacts with the uv radiation coming from the sun to form ozone. The "envelope of air" that reaches from 12km - 50km. This sphere is supposed to harbor ozone (O3) and protect the Earth from harmful incoming UV radiation from the sun. Its depletion by CFCs has created ozone "holes" that are now allowing in more UV radiation that can damage plants, harm human health, and increases the heat that makes it to Earth's surface

Nitrogen Oxides

gases produced by the chemical interactions between atmospheric nitrogen and oxygen when a source of energy, such as a combustion of fuels, produces high temperatures. Nitric Oxide (NO), nitrogen dioxide (NO2), and nitrous oxide (N2O). inhibit plant growth and aggravate health problems such as asthma

Sulfur Oxides

gases produced by the chemical interactions between sulfur and oxygen. Sulfur dioxide (SO2), a colorless and non flammable gas with a strong and gross odor. Sulfur trioxide (SO3), forms when sulfur dioxide reacts with oxygen in the air

Troposphere

the layer of the atmosphere closest to Earths surface is a human made air pollutant. The "envelope of air" closest to Earth's surface that reaches up to about 12km from the ground. This sphere is now inundated with ozone (O3) because of the reactions of human-created primary pollutants NOx and hydrocarbons. This results in a trapping of longwave radiation from the Earth and an overall warming.

Air Pollution

various chemicals added to the atmosphere by natural events or human activities in high enough concentrations to be harmful.

Carbonic Acid

(H2CO3) This weak acid forms two kinds of salts: carbonates and bicarbonates. It can dissolve limestone and marble and therefore has a great impact on manmade structures and natural bedrock of such materials. (Caverns and karst topography are often formed this way). Additionally, this acid's levels are rising in the ocean- leading to coral reef die-offs. Rising CO2 levels from fuel combustion are a main contributor to this acid's increasing presence.

Sulfuric Acid

(H2SO4) Sulfur dioxide (SO2) is the main byproduct produced when sulfur-containing fuels such as coal or oil are burned; when it reacts with water it creates sulfuric acid which can come to Earth as sulfur rain/ deposition.

List four pollutants that are present in photochemical smog, and circle which ones are secondary pollutants.

1. Nitric Oxide (NO) (primary) 2. Carbon Dioxide (CO2) (primary) 3. Hydrocarbons/ HC (such as VOCs) (primary) 4. Nitric Acid (HNO3) (secondary) 5. Peroxyacyl Nitrates (PANS) (secondary) 6. Formaldehyde (secondary) 7. Ozone (O3) (secondary

Clean Air Act

1970, set the standard for modern air quality regulation. Law authorizes the EPA to set limits on the amunt of specific air pollutants permitted everywhere in the united states. he CAA authorizes the EPA to set limits on the amount of specific air pollutants permitted to enter the atmosphere. They focus on six pollutants: lead, particulates, sulfur dioxide (SO2), carbon monoxide (CO), nitrogen oxides (NOx), and ozone (O3). This act has succeeded in reducing these major air pollutants, but most cities are still not up to health standards and are considered "non-attainment" areas.

Define the difference between a primary pollutant and a secondary pollutant

A primary pollutant is a harmful substance emitted directly into the atmosphere, while a secondary pollutant is formed in the atmosphere when a primary pollutant reacts with substances normally found in the atmosphere or with other air pollutants

Oxygen Radical

A single, unstable oxygen atom. These free-floating O atoms can attach themselves to stable O2 molecules and form harmful tropospheric ozone (O3).

Explain how the risk of getting cancer from air pollution differs by ethnic group in Los Angeles, including the effects of income as a potential confounding variable

Despite controlling for factors like income, minority ethnicities tend to suffer higher cancer rates from air pollution. This may be because communities are clustered near areas where point source pollution is high, like near industry, freeways, etc.

Nitric Acid

HNO3) The main industrial use of nitric acid is for the production of fertilizers. It is neutralized with ammonia to give ammonium nitrate. This acid can react violently with metallic and non-metallic materials. It can oxidize them and can potentially be explosive (thus it being used commonly in ammunitions as well).

Volatile Organic Carbon

Hydrocarbon compounds that have low boiling points, usually less than 100ºC, and therefore evaporate readily. Some are gases at room temperature. Propane, benzene, and other components of gasoline are all VOCs. VOCs cause burning eyes and coughing

Describe the chemicals and input of energy that are needed to create stratospheric ozone

Stratospheric ozone (O3) formation process: 1. O2 (atmospheric oxygen) + UV (sunlight) -> O + O (two free oxygen atoms) 2. O (single free oxygen atom) + O2 (atmospheric oxygen) = O3 (stratospheric (good) ozone)

Clarify what Ronald Reagan meant when he said that trees emit more pollution than cars, and why that statement is false

Trees and other plants emit VOCs (volatile organic compounds- a kind of hydrocarbon), which we can sense as smells the plants give off. VOCs are one of the compounds that may form tropospheric ozone or photochemical smog (which is made partially of tropospheric ozone). The issue with this statement is that such VOCs are primary pollutants and are benign until they are able to become secondary pollutants by reacting with NOx or SOx which are emitted by human activities like fossil fuel combustion. Therefore, if such large quantities of SOx and NOx were not emitted into the atmosphere by factors like transportation and industry, these VOCs would not adversely affect the environment

Describe the chemicals and input of energy that are needed to create tropospheric ozone

Tropospheric ozone (O3) formation process: 1. NOx (nitrogen oxides) + HC (hydrocarbons)/ VOCs (volatile organic compounds) -> NO2 (nitrogen dioxide) 2. NO2 + UV (sunlight) -> NO (nitric oxide) + O (free oxygen radical) 3. O + O2 (atmospheric oxygen) -> O3 (tropospheric (bad) ozone)

Clarify in what respects the Clean Air Act was successful, and in what respects there is still room for improvement, with an example from San Diego.

Updated from 1955 to the more modern version of 1970, the CAA authorizes the EPA to set limits on the amount of specific air pollutants permitted to enter the atmosphere. They focus on six pollutants: lead, particulates, sulfur dioxide (SO2), carbon monoxide (CO), nitrogen oxides (NOx), and ozone (O3). This act has succeeded in reducing these major air pollutants, but most cities are still not up to health standards and are considered "non-attainment" areas.

Carbon Monoxide

a colorless, odorless, and tasteless gas produced in the largest of quantities of any atmospheric pollutant except carbon dioxide, is poisonous and interferes with the bloods ability to transport oxygen

Secondary Pollutant

a harmful substance formed in the atmosphere when a primary air pollutant reacts with substances normally found in the atmosphere or with other air pollutants

Primary Pollutant

a harmful substance, such as soot or carbon monoxide, that is emitted directly into the atmosphere. Major ones are nitrogen oxides, sulfur dioxide, particulate matter and hydrocarbons