Rachel Carson, DDT, and air pollution

Interdisciplinary perspectives

• Natural sciences (biology, chemistry, etc.)• Medical sciences (especially epidemiology, the

study of disease and risk factors)• History• Ethics• Economics• Writing and story-telling• National and international perspectives

Historical perspectives

• 1962: Silent Spring • 1969: Natl. Environmental

Policy Act (requiring Enviro Impact Statements)

• 1970: Creation of EPA• 1970+: Clean Air Act• 1972+: Clean Water Act• 1972: U.S. bans DDT• 1973: End. Species Act

Rachel Carson (1907-1964)

“Silent Spring” is a metaphor referring to

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1. Aquifers running dry

2. An imaginary polluted city near Washington DC

3. Loss of songbirds

According to Tina Rosenberg, Rachel Carson didn’t consider

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19% 19%62%1. DDT impacts on farmworkers

2. DDT impacts on malaria

3. DDT impacts on wildlife

Natural Science: Evolution #1 (Sharing)

• To what extent can we design chemicals that harm insects without harming humans?

• To what extent do insects and humans share biological processes?

• “The organic phosphorus insecticides …destroy enzymes… Their target is the nervous system, whether the victim is an insect or a warm-blooded animal.” (p. 18)

Natural Science: Evolution #2 (Resistance)

Natural science: Bioaccumulation

• Each food chain step involves ≈90% loss of energy, e.g., 1 pound of snake comes from 10 pounds of frog.

• If 0% of chemicals are lost, then 1 pound of snake contains the chemical load of 10 pounds of frog.

PBDEs (compounds used in flame retardants) in human breast milk

• “Germ theory” of disease vs. “miasma theory” (“bad air” / “mal aire” / “malaria”)

• John Snow’s map of London in 1854, showing cholera deaths

• Clustered around Broad Street pump!

Epidemiology: Scientific detective work about diseases and their causes

Annual % change in incidence and death rates, 1994-2003 (cancer.gov)

Generating and testing hypotheses about cancer

• What could cause cancer incidence rates to increase or decrease?

• What could cause cancer death rates to increase or decrease?

• How to test hypotheses about cancer?• These are not academic questions!– Breast cancer: 1 in 8 will get it, 1 in 33 will die from it. – Prostate: 1 in 6 will get it, 1 in 34 will die from it.

• PS. Conduct self-exams for breast, testicular cancers!

Epidemiology: Scientific detective work about diseases and their causes

1) Establishing cause-and-effect links between pollution and health or other impacts is hard!

2) Precautionary principle? “When an activity raises threats of harm to human health or the environment, precautionary measures should be taken, even if some cause-and-effect relationships are not fully established scientifically.” (Wingspread Statement, 1998)

Case study: Toxics http://www.epa.gov/tri/

Case study: Toxics

• Only a quarter of the 82,000 chemicals in use in the U.S. have ever been tested for toxicity. Each year industry seeks to add 1,700 new compounds.

• How (if at all) to apply precautionary principle? (Retroactively?)

• Is the absence of evidence the evidence of absence?• “Ignorance is not a solvable problem, but rather an

inescapable part of the human condition. The advance of knowledge always carries with it the advance of some form of ignorance.” (David Orr)

Health effects research options

• Animal toxicology and in vitro methods– Controlled; hard to extrapolate

• Controlled human studies– Controlled; small samples; short exposures

• Analysis of the real world– Asks the right question– Estimates health outcomes and exposures– Confounding variables?

A brief history of air pollution, mostly focused on the U.S.

• Air is a basic necessity for life (without O2 we get brain damage in ~3 minutes);

• Lungs are readily irritated by noxious gases (e.g. O3, SO2, smoke, etc.);

• Lungs are also a good conduit for absorption into bloodstream of toxics such as Pb [lead], CO [not CO2!], benzene, etc.

• Due to low mass of earth’s atmosphere and sometimes poor dispersion, air can be readily polluted.

History of major air pollution “incidents”Belgium, 1930-- 63 deaths;Donora, PA,1948--20 deaths;London, 1952--4000 deaths;New York, 1966--166 deaths.

These incidents all occurred in heavily industrialized regions, under severe meteorological conditions (strong inversions with poor ventilation).

London Killer Fog

December 1952 A toxic mix of dense fog and sooty black coal smoke killed thousands of Londoners in four days. It remains the deadliest environmental episode in recorded history.

The Clean Air Act (CAA)• Used as a model for laws in other countries.• Original in 1970, with major revisions in

1977, 1985, 1990, 1995 to deal with toxics and stratospheric ozone in addition to 6 originals:

• CO (not CO2!) and Pb (Lead) and SOx.• NOx and VOCs (Volatile Organic Compounds),

which produce ground-level ozone (“smog”)] • Particulate matter (“rocks”): PM10, PM2.5

PM10 and PM2.5

The health risks from particulates are due in part to the small size. The smaller the size, the bigger health risk. PM2.5 stays in the air much longer than PM10, taking days to weeks to be blown away.

Acute versus chronic health effects

• Acute effects are those that appear to be associated with air pollution on the same day or 1-4 days prior to the outcome

• Chronic health effects—sometimes called longitudinal—are over 10-20 years or more. In children and young adults this can be a lifetime exposure.

Good news: Many local air pollutants have decreased over time…

Source: U.S. EPA

…even as populations and economic activity have risen!

Source: U.S. EPA

More good news: The Clean Air Act passes a Cost-Benefit Analysis!

In the 1990 CAA amendments, congress required EPA to conduct a cost-benefit analysis on the CAA

“Final Report to Congress on Benefits and Costs of the Clean Air Act, 1970-1990”

Annual Costs: $25 billion (mainly compliance costs)Annual Benefits: $1.1 trillion (range 0.3-2.5 trillion)

Mainly avoided deaths, avoided hospitalizations and avoided lost IQ points in children)

A “no brainer”...

Bad news: Air pollution is still a problem in the U.S.

• The CAA specifies that EPA should set air standards—called the National Ambient Air Quality Standards (NAAQS)—in order to protect the most sensitive members of the public with an adequate margin of safety.

• Costs or other economic considerations are not to be considered.

• NAAQS should be re-evaluated by EPA every 5 years to ensure they are consistent with best scientific data. This leads to a “ratchet effect.”

Currently, about 100 million people in the US live in areas that don’t meet the O3 standard.

Note that in 2007, EPA has proposed a new lower (tougher) O3

standard. Final rules will be announced in 2008.

Non-attainment areas for 8-hour O3 standard

Currently, ~50 million people in the US live in areas that violate the PM2.5 standard. By one estimate, there are 64,000 premature deaths in the US due to PM, at levels above and below the standard.

PM2.5 Non-attainment areas

Orange: Areas that exceed only the annual std (15 ug/m3).Yellow: Ares that exceed only the 24 hour std (65 ug/m3).

Red: Areas that exceed both.

New PM2.5 Non-attainment areas (2007)

Orange: Areas that exceed only the annual std (15 ug/m3).Yellow: Ares that exceed only the 24 hour std (35 ug/m3).

Red: Areas that exceed both.

International perspectives

• “In her 297 pages, Rachel Carson never mentioned the fact that by the time she was writing, DDT was responsible for saving tens of millions of lives, perhaps hundreds of millions. DDT killed bald eagles because of its persistence in the environment. Silent Spring is now killing African children because of its persistence in the public mind.” (Rosenberg 2004)

We should use DDT on malaria

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1. Strongly Agree2. Agree3. Neutral4. Disagree5. Strongly Disagree

Beijing Smog

According to the World Bank, 16 of 20 of the world’s most polluted cities are in China.

Wood smoke as a pollutant

Wood smoke as a pollutant

Wood smoke as a pollutant

Global Air Pollution: Science and Implicationsby Dan Jaffe, UW-Bothell

Research team (R to L): Will Hafner, Duli Chand, Phil Swartzendruber, Mary Howisey, Dave Reidmiller, Jeremy Smith

and Dr J (not shown Emily Fischer)

Most air pollution is from local sources, but as we move to lower standards, background air becomes more

important…

Figure: EPA Atmospheric Deposition Handbook, 2001.

Background air

Mean wind vectors for April700 mb (~10,000 feet elevation)

PHOBEA* Study Area

Aircraftprofiles

CPO

*Photochemical Ozone Budget of the Eastern North Pacific Atmosphere.

The view from Cheeka Peak

Cheeka Peak 10 meter

Sampling Tower

Vertical Profiles using Beechcraft Duchess

• Twin (piston) engine aircraft• Unpressurized cabin• Maximum flight altitude 6km, 4 hours useable flying time• Maximum instrument payload ~240 kg• Maximum instrument volume ~1.5m3

• Maximum power ~1 kw• Available locally (Northway Aviation, 20min from lab) • $250/hour including pilot.

How important is background air?

Background concentrations are partly natural and partly due to global anthropogenic sources.

New PM std

New O3 stdCurrent O3 std

Current PM std

The blue bars show the mean conc. of O3 and PM2.5 in the air arriving to Wash. State from the Pacific.

TOMS Aerosol Index (AI) for mid-April 2001

April 12, 2001

April 8, 2001

April 14, 2001

Satellites give useful information on large transport events, however this data is qualitative, lacks altitude and chemical information and is often obscured by clouds. To put this in perspective, we have identified about 15 transport events, but only 3 have been identifiable with satellite data. The April 2001 dust event was a biggie…

How did the April 2001 Asian dust episode influence air quality in several urban areas of the U.S.?

Old std

New std

More bad news: Global warming may worsen ground-level ozone (“smog”)

Source: Jane Koenig

But overall, what Tom Lehrer wrote is (mostly) no longer

true…If you visit an American cityYou will find it very pretty

Just two things of which you must be aware

Don’t drink the water and don’t breath the air!