The major air pollutants Carbon monoxide (CO) Nitrogen oxides (NOx) Ozone (O3) Particulate matter (PM-10, PM-2.5) Sulfur dioxide (SO2) Lead (Pb) Greenhouse gases (CO2 and others)

Carbon Monoxide Impacts: Blood oxygen levels Headaches, alertness, death Sources: Vehicles (plus others) Source: Ref. (1)

Carbon Monoxide CO levels are improving, but still a problem in many colder urban areas. Source: Ref. (1)

Nitrogen Oxides Impacts: Respiratory irritant Leads to ozone formation Leads to acidic deposition of HNO3 Sources: High-temperature combustion Source: Ref. (1)

Ozone Impacts: Respiratory irritant Plant damage (forest, crops) Sources: Produced in the atmosphere

Ozone A major urban and regional pollution problem Source: Ref. (1)

Particulate Matter Definitions: PM10 = PM < 10 um Impacts: Lung irritation Visibility

Particulate Matter Impacts: Lung irritation Visibility Sources: Depends on particle size Source: Ref. (1)

Particulate Matter Impacts: Visibility at Shenandoah Nat’l Park Source: Ref. (2)

Sulfur Dioxide Impacts: Eye and lung irritation Acidic deposition of sulfuric acid. Damage to limestone and concrete. Sources: Source: Ref. (1)

Sulfur Dioxide Impacts: Acidic deposition of H2SO4. Pure water pH = 5.6 Source: Ref. (3)

Lead Impacts: Brain and kidney damage. Sources: Leaded gasoline was dominant, but Pb is no longer in U.S. on-road gasoline Source: Ref. (1)

Lead Impacts: Brain and kidney damage. Sources: Metals processing, battery mfr, etc Source: Ref. (1)

Greenhouse Gases Impacts: Global climate change Gases: Sources: See : Ref. (4)

What determines the average temperature of the earth? The Greenhouse Effect What determines the average temperature of the earth? 1. Source: Ref. (5)

What determines the average temperature of the earth? The Greenhouse Effect What determines the average temperature of the earth? 2.

What determines the average temperature of the earth? The Greenhouse Effect What determines the average temperature of the earth? 3.

The Natural Greenhouse Effect Average solar radiation in: 236 W per square m Without the atmosphere, temperature would be: -2 F Greenhouse effect of natural water and CO2: 148 W per square m (1 lightbulb every 2 feet) Result: Average temperature = 57 F

The Human Contribution Source: Ref. (6)

The Human Contribution Total effect until now: about 2.3 W / m2 (1 light bulb every 15 feet) Predicted effect by 2050: Up to 7 W / m2 (1 light bulb every 9 feet)

Expected Impacts: More precip, more energy in weather More extreme weather events are predicted On average, more precipitation, but region-by-region, some will be wetter, some drier.

CO2 Emissions by Nation Developing nations will soon be the largest CO2 producers, but most CO2 in the atmosphere today came from to industrialized nations Source: Ref. (8)

Particulate Activities Light scattering Particles most effectively scatter light. Uncontrolled car exhaust scatters blue light. Atmospheric gases also scatter, blue more than red. Large concentrations of particle mixtures scatter all colors  white haze

Haze in Los Angeles Source: Ref. (9)

Local Issues Vehicle emissions Sources of CO, CO2, particulates, NOx, VOCs Strategies for reducing emissions Fuel economy (all, proportional to fuel use) Catalytic converters and no exhaust system leaks (CO, NOx, particulates, VOCs – no effect on CO2)

Local Issues 2. Snowmobiles and wood stoves Snowmobiles: 2-cycle engines are light, but of the C burned, ~1/3 is fully burned and emitted as CO2. ~1/3 is emitted as CO. ~1/3 is not burned at all and released as gasoline.

Local Issues 2. Snowmobiles and wood stoves Wood stoves: Newer wood stoves have catalysts or secondary combustion; those without emit more particles and VOCs Can compare by viewing chimney exhaust (don’t be fooled by water fog) Wood stoves can be a major source of indoor air pollution when smoke is pulled in from outdoors.

Local Issues 3. Indoor air pollution Key issues: Radon Molds Particles and smokes

PCBs “PolyChlorinatedBiphenyls” Used in transformers, as hydraulic fluids, … Chemically stable, thermally stable, high dielectric constants. Not broken down in the environment. Accumulate in animal fats. Cause birth defects. Manufacture in U.S. banned in 1977.

Stratospheric Ozone Antarctic ozone hole Source: Ref (13)

Stratospheric Ozone Declining outside of Antarctica Source: Ref (5)

Stratospheric Ozone Impact on UV radiation Source: Ref (5)

Stratospheric Ozone Success of the Montreal Protocol Source: Ref (18)

Stratospheric Ozone Some common questions CFCs are heavier than air, so cannot reach the stratosphere. The ozone hole is natural, and is caused by volcanoes and oceans. Ozone depletion occurs only over Antarctica.

Roles of Ozone in the Lower Atmosphere Human health effects (urban and rural). Causes forest and crop damage (regional).

Ozone is an issue in urban areas and in large regions Source: Ref (17)