Saturday, 23 May 2015

How We Contribute to Air Pollution and Climate Change

How We Contribute to Air Pollution and Climate Change

The pollutants released into the atmosphere cause local air pollution. However, they also cause regional air pollution, as with huge plumes of smoke covering a large area, and acid rain. Beyond that, we are emitting such a high level of pollutants that they are causing serious global environmental problems: climate change and ozone depletion. The human race has become capable of affecting the atmosphere that encircles the Earth, and the very planet itself.

MAIN (COMMON) POLLUTANTS

Pollutant

Description and Sources

Health Impact

Environment

Particulate Matter (PM)

Dust, soot, and tiny bits of solid material.
PM10 — Particles smaller than 10µm (microns) in diameter.
Far too small to see — 1/8th the width of a human hair.
• Road dust; road construction
• Mixing and applying fertilizers/ pesticides
• Forest fires
• Coarse particles irritate the nose and throat, but do not normally penetrate deep into the lungs. • PM is the main source of haze that reduces visibility.
• It takes hours to days for PM10 to settle out of the air.
• Because they are so small, PM2.5 stays in the air much longer than PM10, taking days to weeks to be removed.
• PM can make lakes and other sensitive areas more acidic, causing changes to the nutrient balance and harming aquatic life.

PM2.5 –Particles smaller than 2.5µm in diameter • Combustion of fossil fuels and wood (motor vehicles, woodstoves and fireplaces)
• Industrial activity
• Garbage incineration
• Agricultural burning
• Fine particles are small enough to make their way deep into the lungs. They are associated with all sorts of health problems — from a runny nose and coughing, to bronchitis, asthma, emphysema, pneumonia, heart disease, and even premature death.
• PM2.5 is the worst public health problem from air pollution in the province. (Research indicates the number of hospital visits increases on days with increased PM levels).

Ground level Ozone (O3)

Bluish gas with a pungent odour
• At ground level, ozone is formed by chemical reactions between volatile organic compounds (VOCs) and nitrogen dioxide (NO2) in the presence of sunlight.
• VOCs and NO2 are released by burning coal, gasoline, and other fuels; and naturally by plants and trees.
• Exposure for 6-7 hours, even at low concentrations, significantly reduces lung function and causes respiratory inflammation in healthy people during periods of moderate exercise. Can be accompanied by symptoms such as chest pain, coughing, nausea, and pulmonary congestion. Impacts on individuals with pre-existing heart or respiratory conditions can be very serious.
• Ozone exposure can contribute to asthma, and reduced resistance to colds and other infections.
• Ozone can damage plants and trees, leading to reduced yields.
• Leads to lung and respiratory damage in animals.
• Ozone can also be good: the ozone layer above the earth (the stratosphere) protects us from harmful ultraviolet rays.

Other Pollutants

• sulphur dioxide (SO2)
• carbon monoxide (CO)
• nitrogen dioxide (NO2)
• total reduced sulphur (TRS)
• volatile organic compounds (VOCs)
• persistent organic pollutants (POPs)
• lead (Pb)
• polycyclic aromatic hydrocarbons (PAHs)
• dioxins and furans
Most of these pollutants come from combustion and industrial processes or the evaporation of paints and common chemical products.
• The health impacts of these pollutants are varied.
• Sulphur dioxide (SO2), for example, can transform in the atmosphere to sulphuric acid, a major component of acid rain.
• Carbon monoxide is fatal at high concentrations, and causes illness at lower concentrations.
• Dioxins and furans are among the most toxic chemicals in the world.
• While some of these pollutants have local impact on the environment (e.g., lead) or are relatively short lived (NO2) some are long lived (POPs) and can travel the world on wind currents in the upper atmosphere.
 
Processes such as fossil fuel burning in industry, motor vehicles and buildings emit pollutants that cause local and regional pollution. These pollutants include particulate matter (PM) and ground-level ozone (O3) — the key ingredients of smog — along with nitrogen oxides (NOx), sulphur oxides (SOx), volatile organic compounds (VOCs) and carbon monoxide (CO).
The same processes also release greenhouse gases, mainly carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), which are linked to global climate change.
In some cases, air pollutants contribute to climate change, and greenhouse gases contribute to air pollution:
  • Air pollutants such as ground-level ozone and soot (a portion of particulate matter) contribute directly to global warming, which is linked to climate change.
  • Methane, one of the most important greenhouse gases, is a major cause of increased ground-level ozone.
Climate change itself may have a direct impact on air quality.

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