envr 1000 - unit 4, atmosphere and climate change, pt 2

Primary air pollutants

Carbon oxides, nitrogen oxides, sulfur dioxide, particulate matter, hydrocarbons, chlorofluorocarbons

Secondary air pollutants

Ozone, sulfur trioxide, and some acids formed through atmospheric reactions

Particulate matter

Solid or liquid particles suspended in air such as dust, soot, lead, asbestos, microorganisms, and sulfuric acid droplets

Particulate matter effects

Can cause toxic or carcinogenic effects, corrode metals, erode buildings, and scatter sunlight

PM10

Particulate matter smaller than 10 micrometers in diameter

PM2.5

Particulate matter smaller than 2.5 micrometers and more dangerous because it penetrates deeper into lungs

Nitrogen oxides (NOx)

Gases formed when nitrogen and oxygen react during combustion

Nitrogen oxides effects

Aggravate asthma, contribute to photochemical smog and acid deposition, corrode metals

Sulfur oxides (SOx)

Gases produced when sulfur reacts with oxygen

Sulfur oxides effects

Contribute to acid deposition, damage stone and metals, irritate respiratory system

Carbon monoxide (CO)

Colorless, odorless, poisonous gas that reduces the blood’s ability to carry oxygen

Carbon dioxide (CO2)

Greenhouse gas associated with climate change

Hydrocarbons

Organic compounds containing carbon and hydrogen

Hydrocarbon effects

Some are respiratory irritants or carcinogens and contribute to photochemical smog

Methane

Greenhouse gas hydrocarbon linked to global warming

Ozone (general)

Atmospheric gas that can be beneficial or harmful depending on location

Stratospheric ozone

Ozone layer that protects Earth from harmful ultraviolet radiation

Tropospheric ozone

Ground-level ozone that contributes to smog and acts as a respiratory irritant

Sources of air pollution

Transportation and power plants are the main human sources

Transportation sources

Cars, trucks, and construction equipment produce mobile emissions

Power plant sources

Burning coal releases large amounts of air pollutants

Industrial pollution sources

Chemical, metal, and paper industries

Agricultural burning

Burning forests or fields releases pollutants into the atmosphere

Effects of air pollution

Corrodes materials, injures organisms, harms human health, reduces crop productivity, reduces visibility

Human health impacts

Can cause eye irritation, respiratory inflammation, immune suppression, and chronic respiratory diseases

Ozone layer

Region of the stratosphere containing ozone that blocks ultraviolet radiation

Chlorofluorocarbons (CFCs)

Synthetic chemicals used in refrigerants and solvents that destroy ozone molecules

Ozone depletion

CFCs release chlorine atoms that break ozone into oxygen molecules

Ozone hole

Major thinning of ozone over Antarctica discovered in 1985

Montreal Protocol

International agreement in 1987 that reduced CFC use by about 95%

Ozone recovery

Ozone layer expected to recover after about 2050

Effects of ozone depletion

Increased UV radiation leading to skin cancer, cataracts, weakened immunity, and ecosystem disruption

Air pollution control technologies

Filters, scrubbers, catalytic converters, and fuel improvements reduce emissions

Scrubbers

Devices that chemically remove pollutants from smokestack emissions

Catalytic converters

Devices in vehicles that reduce carbon monoxide and hydrocarbon emissions

Low-emission zones

City areas where vehicle traffic is restricted to reduce air pollution

Benefits of low-emission zones

Improved air quality, reduced congestion, and better walkability

Indoor air pollution

Accumulation of pollutants inside buildings

Indoor pollution sources

Solid fuel burning, chemicals, smoke, and poor ventilation

Indoor air pollution deaths

World Health Organization estimates about 1.6 million deaths annually from indoor cooking smoke

Pea-soupers

Thick yellowish smog caused by coal burning in 19th century London

Great Smog of London (1952)

Four-day smog event causing about 12,000 deaths

Temperature inversion

Condition where temperature increases with altitude, trapping pollutants near the ground

Temperature inversion effects

Prevents vertical mixing of air and causes pollution buildup

Cities prone to inversions

Los Angeles, Mexico City, Rio de Janeiro, Salt Lake City

Indoor contaminants in developed countries

Radon, cigarette smoke, carbon monoxide, nitrogen dioxide, formaldehyde, pesticides, ozone, asbestos

Sick building syndrome

Health symptoms such as headaches, fatigue, and respiratory issues caused by indoor air pollution

Radon

Colorless, odorless radioactive gas produced by uranium decay in the Earth’s crust

Radon health risk

Second leading cause of cancer in Canada

Radon in homes

Radon can seep into buildings from the ground and accumulate to dangerous levels

Radon prevalence in Canada

About 18% of Canadian homes have unsafe radon levels

Radon and energy-efficient homes

Tightly sealed homes may trap more radon due to reduced ventilation