1. Ground-Level Air Pollution

2. SMOG Smog: combination of smoke and fog Smoke + fog (London-type) Smog
results from the burning of coal and other raw materials in the presence of a fog
Photochemical (Los Angeles-type) Smog
results from the emissions of hydrocarbons and oxides of nitrogen in the presence of sunlight

3. London-type smog
Several deadly London-type smog events in the 19th and 20th centuries, such as the one on
December 1952 (London): >4000 deaths!

5. Photochemical (LA) smog
“soup” of gases and aerosol particles
some of the substances are emitted (primary pollutants) whereas others form chemically or physically in the air (secondary pollutants)
involves hundreds of different reactions (our atmosphere is a “giant chemical reactor”)
sunshine: vital ingredient
relatively little movement of the air masses
relatively high levels of ozone at ground level (“ozone in the wrong place”)

9. LA
Smog

10. Persistent Organic Pollutants (POPs): History and Characteristics
(1962)
By the 1960s, many compounds were discovered to be harmful, not only through environmental studies (leading to Carson’s coverage of DDT in Silent Spring in 1962) but also industrial accidents that led to high exposure. By the 1970s and 1980s, several of these compounds were banned for their toxic side effects in the United States.
While these compounds were largely successful due to their persistence in the environment, particularly for pesticides, this unintentionally led to their accumulation and spread over long global distances.
Environmental observation, industrial accidents showed harmful effects

12. Source/Receptor Regions in Los Angeles
121
Source/Receptor Regions in Los Angeles

13. Particulates in Air Pollution
Although most regulations of air pollution focus on gases,
aerosol particles cause more visibility degradation and possibly
more health problems than gases.

14. Aerosols: liquid and solid particles suspended in the air
- Natural and Anthropogenic Sources

16. Chapter One: Persistent Organic Pollutants (POPs)
Production began in 1930s-1940s
Pesticides (DDT, Aldrien/Endrin, HCBs, Mirex)
Fungi, lice, malaria, typhoid
Flame retardants (PBDEs)
Electrical insulation (PCBs)
Advantage: Long half-lives (months-years)
Production of compounds now known as persistent organic pollutants, or POPs, began as early as the 1930s around the globe. Some, including DDT, Aldrien, hexachlorobenzenes (HCBs), and Mirex, served as effective and persistent organopesticides for controlling spread of fungi, lice, and major post-World War II diseases like malaria and typhoid. Others were useful for a variety of reasons, including brominated flame retardants for controlling fires and polychlorinated biphenyls (PCBs) for electrical insulation, while some were unintentional industrial byproducts, including dioxins (PCDDs) and furans (PCDFs).

17. Persistent Organic Pollutants (POPs): History and Characteristics
Organochlorine Pesticides
Table 1. "Dirty dozen" most hazardous POPs in the environment.
POP
Year Banned in U.S.
Soil Half-Life (yrs)
Aldrin
1987*
N/A
Chlordane
1988 1
DDT
1972*
10-15
Dieldrin 5
Endrin
1980* 12
Heptachlor 2
HCB
1966
Mirex
1976 10
Toxaphene
1982*
PCBs
Dioxin
10-12
Furan
*Banned for most uses.
Stockholm Convention,
Dioxins and Furans
In 2004, the Stockholm Convention of 121 parties identified 12 POPs as “most hazardous” to human health, referred as the “dirty dozen.” These compounds fell into three classes: organochlorine pesticides, dioxins and furans, and polychlorinated biphenyls.
Polychlorinated Biphenyls (PCBs)

18. Persistent Organic Pollutants (POPs): History and Characteristics
Organochlorine Pesticides
Household and agricultural pesticides/fungicides
300+ Da, halogenated (degradation resistance)
Semi-volatile (long-range atmospheric transport)
Lipophilic (ease of transport across PMs)
Bioaccumulation
’97 AMAP: PCBs in Canadian caribou/wolves
Dioxins and Furans
Industrial byproducts (combustion, unintentional)
Since the Stockholm Convention’s activation in 2004, many other POPs have been identified that pose a health risk.
All hazardous POPs share three common characteristics. They are persistent, in that they are resistant to environmental or biochemical degradation, usually due to a high degree of halogenation. They are often semi-volatile, with a vapor pressure around 1000 Pa, which allows evaporation into the atmosphere for long-range travel before condensing in colder regions. Their high molecular weights (usually at or above 300 Da) make them more difficult to break down, and their lipophilic nature makes them more readily soluble in fatty tissue, increasing bioaccumulation.
Polychlorinated Biphenyls (PCBs)
Electrical insulation leeching
Polybrominated diphenyl ethers (PBDEs), hexachlorobenzene (HCB), chlorophenols, PFOS, Lindane, PBBs…

19. Persistent Organic Pollutants (POPs): History and Characteristics
Byproducts in first-world countries (dioxins/furans, PCBs)
Still produced in second-world countries
No affordable alternatives (DDT)
PBDEs for export (no PCBs)
Fish oil, salmon feeds
Main use, particularly insecticides, is in second-world countries with no affordable, environmentally friendly alternative (DDT still used). Also often byproducts of industry in first-world countries, leading to cross-country drifting of all types (DDT can be found here and PCBs found elsewhere). Plus, we produce some, including PBDEs, for export despite restrictions for domestic use. POPs show high levels in fish oil as well due to exposure in bodies of water, and builds up with oil-containing salmon feed used in U.S. farming fisheries (though some steps with vegetable oil alternative are being used to lessen this).

20. Persistent Organic Pollutants (POPs): History and Characteristics
Causes
Effects
Enzymatic inhibition (DDT)
DNA hypomethylation
Estrogenic qualities
50% POPs = estrogenic disruptors
Decreased fertility (PBDEs, PFOA, PFOS)
Fetal malformations (PBDEs)
Behavior/memory changes (PBDEs, pesticides, PCBs)
Impaired learning ability (PBDEs)
Hormone disruption (all)
Hepatotoxicity (PFOA, PFOS)
Arthritis, Breast Cancer, Diabetes (pesticides)
POPs are dangerous not only for their widespread presence, but their highly toxic effects on animals and humans. Accumulation of PBDEs have been shown to decrease sperm count and delay puberty14, cause fetal malformations if exposed neonatally15, cause behavior changes and alter memory and learning ability16, and disrupt hormone levels17. Perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), forms of perfluorinated compounds (PFCs), have been associated with hepatocarcinoma, liver weight increase, and other hepatotoxic effects after its discontinuation by 3M, its biggest U.S. producer, as well as impaired sperm quality and overall fecundity18. Organochlorine pesticides have been associated with diabetes, breast cancer, arthritis, DNA hypomethylation, and neurological symptoms, and PCBs have been shown to cause birth defects and cognitive impairment19,20. The most common source of these compounds is believed to be dietary9.

23. Visibility Degradation

25. Health Effects of Air Pollutants

26. Health Effects of Air Pollutants
Lung functions
Lung growth
Irregularities in heartbeats
Long-term [chronic] exposure
Respiratory illness
Asthmatic attacks
Angina pain
Hospital admissions
Emergency room visits
Pulmonary deaths
Cardiovascular deaths

27. Health Effects of Outdoor Air Pollutants Gaseous Pollutants

28. Regulation in the U.S. Air Pollution Act of 1955 Clean Air Act of 1963
Motor Vehicle Air Pollution Control Act of 1965
Air Quality Act of 1967
Clean Air Act Amendments of 1970
Clean Air Act Amendments of 1977
Clean Air Act Amendments of 1990
Clean Air Act Revision of 1997
New Clean Air Act Regulations (2002/2003)
New Source Review (NSR) modification

29. INDOOR AIR POLLUTION
Although epidemiological studies have found an association between short-term exposure to outdoor particulate air pollution and health problems, people spend most of their times indoors, and concentrations of aerosol particles are often greater indoors than outdoors.

32. Sources of Major Indoor Air Pollutants