Urban Air Pollution

Nada Nabulsi & Thea Tadros

Sources

• Particulate Matter: smoke, dirt and dustfrom factories, farming, and roads• Ground Level Ozone (Tropospheric level)• Carbon Monoxide (Combustion of fossil fuels)• Nitrogen Dioxide (vehicles, power plants, etc.)• Sulfur Dioxide (fossil fuel combustion)• Lead (emission from industrial sources)• Waste Deposition (Landfills)

What is the Troposphere

Ozone can be found in the troposphere, the lowest layer of the atmosphere. Tropospheric ozone (often termed "bad" ozone) is man-made, a result of air pollution from internal combustion engines and power plants.

Ozone ProductionOzone production from NOx pollutants: When fossil fuels are burned, two of the pollutants emitted are hydrocarbons (from unburned fuel) and nitrogen monoxide (nitric oxide, NO) Oxygen atoms freed from nitrogen dioxide by the action of sunlight attack oxygen molecules to make ozone. Nitrogen oxide can combine with ozone to reform nitrogen dioxide, and the cycle repeats.

Tropospheric Ozone

. Nitrogen monoxide reacts with oxygen to form nitrogen dioxide (NO2), a brown gas that contributes to urban haze. Nitrogen dioxide can also absorb sunlight and break up to release oxygen atoms that combine with oxygen in the air to form ozone.Ozone is a toxic gas and an oxidizing agent. It damages crops and forests, irritates eyes, can cause breathing difficulties in humans and may increase susceptibility to infection. It is highly reactive and can attack fabrics and rubber materials

Photochemical smog is a mixture of about one hundred primary and secondary pollutants formed under the influence of sunlight. Ozone is the main pollutant. The frequency and severity of photochemical smog's in an area depend on local topography, climate, population density and fossil fuel use. Precipitation cleans the air and wind disperse the smog. Thermal inversions trap the smog's in valleys (for example, Los Angeles, Santiago, Mexico City, Rio de Janeiro, São Paulo, Beijing) and concentrations of air pollutants can build to harmful and even lethal levels.

Photochemical smog.

Educate, Legislate and Remediate Educate: Measures to reduce fossil fuel combustion should be considered, for example, reducing demand for electricity and private cars and switching to renewable energy. Clean up measures, such as, ‑catalytic converters. Catalytic Converters are vehicle emission control devices that convert toxic pollutants in exhaust gas to less toxic pollutants.

Legislate: Urban Air Pollution is local thus there is no legislation for it but the kyoto protocol can help decrease it as it reduces CO2 emissions which is one of the causes of Urban Air Pollution

Remediate:

Particulate Control:• Afforestation(Planting more trees) can help get rid of

particulate matter. • Particulate Scrubbers • Electrostatic precipitator

Renewable Energy (windmills, solar panels, etc.)Prevention of Nuclear Plants

They are very costly and time consuming they do not remove urban air pollution completely they just prevent its increasing. Some of the solutions may not be suitable for certain countries.