Air Quality and Pollution

Posted on Aug 24, 2024 in Geology

Composition of the Atmosphere

Nitrogen: 78%

Oxygen: 21%

Argon: 1%

Carbon Dioxide: 0.04% (important because it’s involved in the greenhouse effect. Plants need it, and it is produced by us.)

Structure of the Atmosphere

Exosphere: 1000 km

Thermosphere (Ionosphere): 200 km

– Temperature increases because X-rays are absorbed.

Mesosphere: 70 km

– Temperature decreases, gases are less dense.

Stratosphere: 15 km

– Temperature increases as we move up.

– Ozone Layer: 35 km

– UV rays are absorbed here (main reason for the temperature increase).

Troposphere

– As we move up, the temperature gets lower at first.

– All atmospheric phenomena happen here.

Air Pollutants

  • Sulfur Dioxide: Causes acid rain.
  • Carbon Monoxide: Poisonous gas, it reacts with blood and can be fatal.
  • Nitrogen Dioxide: Acid rain, causes breathing problems, can worsen asthma.
  • Particulates: Make things dirty, can be breathed into your lungs and worsen lung infections or asthma.

Factors Influencing Air Quality

The quality of the air depends on two things:

  1. Emissions: Vehicles, power stations, industry, and other sources release pollutants into the air. Homes and factories are called stationary sources. Most emissions come from cars and lorries (mobile sources).
  2. Weather: Pollutants are mixed and carried around by winds. Wind can move pollutants across borders.

Primary Pollutants: Human activities add pollutants directly to the atmosphere.

Secondary Pollutants: They appear from chemical reactions.

Acid Rain

pH < 6.5. It can be rain, snow, or solid particles.

  • Sulfur and nitrogen from fossil fuels are converted to oxides during combustion.
  • SO2 and NOx mix with water vapor, forming acids.

Effects of Acid Rain

  • Soil becomes very acidic, leading to leaching of minerals (leaching is when rain washes down minerals from plants).
  • Water in lakes and rivers becomes acidic.
  • Plants die.

Solutions to Acid Rain

  • Scrubbers and catalytic converters.
  • Clean fuel to remove sulfur and prevent sulfuric acid formation.
  • Add crushed limestone to neutralize the acidic conditions of the water.

Desertification

Desertification is a major problem in Spain, a consequence of deforestation, leading to the loss of fertile soil.

Hole in the Ozone Layer

The ozone layer is depleting and getting thinner.

  • Caused by pollutants like CFCs (stable chlorofluorocarbons).
  • UV radiation has direct impacts on humans, including skin cancer and cataracts.
  • Radiation levels are higher in Australia, New Zealand, and South America (near Antarctica).
  • The Montreal Protocol, signed in 1987, prohibits the use of CFCs and promotes alternative refrigerants.

Technology for Improved Air Quality

  • Less fuel consumption and reduced pollution.
  • Catalytic Converters added to car exhaust systems: Waste gases (CO and NO) pass through a metal honeycomb structure coated with a thin layer of platinum (catalyst).

CO + O2 ————————–> CO2

NO + CO ————————–> N + CO2

  • Unleaded Petrol: Lead and particulates (small pieces of unburned carbon) in the atmosphere or human blood harden and are not easily absorbed. Unleaded petrol is used because lead damages the catalyst coating in converters.

Cleaner Fuels

  • Cleaner Fuel: Remove sulfur compounds (impurities) from natural gas and coal (used in power stations and domestic heating).
  • Low-sulfur petrol is now available.
  • Use of hydrogen as fuel, producing only water as a byproduct.
  • Research on new fuels.

Reducing Pollutants from Power Stations

  • Burning coal and natural gas produces CO2.
  • Impurities release SO2, contributing to acid rain.
  • SO2 can be treated with a spray of powdered lime (calcium oxide) and water.

SO2 + O2 + lime ————–> Solid Calcium Sulfate (CaSO4)

  • Reduce the release of SO2 gas.

Government and Individual Actions for Air Quality Improvement

  • International Agreements: Kyoto Protocol (revisions in Copenhagen, Durban, and Doha), Montreal Protocol, etc.
  • Sustainable Development: Meeting people’s needs without compromising the environment for future generations.
  • Financial Incentives:
    • Car tax (higher excise duty for larger cars), fuel duty, energy efficiency grants.
  • Laws and Regulations.

Global Warming

Global warming is a pressing environmental problem.

Greenhouse Effect

Solar rays heat the Earth. When the Earth loses heat, it’s in the form of infrared radiation, which gets trapped, increasing the Earth’s temperature.

Effects of Global Warming

  • Polar ice is melting.
  • Sea levels are rising, affecting tourism in Spain.
  • Loss of biodiversity.

Pollutants: CO2, CH4 (from grazing animals), water vapor, combustion of fossil fuels (oil, coal, natural gas).

Radiation Models

Two types:

  1. Ionizing Radiation: Energetic enough to change the energy levels of electrons.
  2. Non-Ionizing Radiation

Effects of Absorbing Non-Ionizing Radiation

  • Microwave and Radio: Electric currents in metals.
  • Radiation: Heating effects (increased vibration).
  • Visible Light Radiation: Chemical changes (cones, rods in eyes).

Ionizing Radiation

  • UV, X-ray, Gamma Radiation: Matter ionization (ions).

(Ionizing Radiation)

Photons: Energy packets of radiation.

Intensity Depends On: Number of photons and energy per photon.