Environmental and Health Impacts of Urbanization

Joyce E. Rosenthal

January 15, 2004

Mailman School of Public Health

Environmental Health Sciences Division

Today’s Talk

Overview of some major environmental impacts of contemporary urbanization in the U.S.:

Water quality

Air quality

Urban heat island effect

Biodiversity loss

Major Points

In the US (and increasingly other nations), recent urbanization has become a process of “spreading out” – the vast expansion of metropolitan regions.

The adverse ecological impacts that stem from low-density urbanization are associated with adverse public health impacts

The public health and planning professions are challenged to work together to understand the impact of the built environment on health, and build communities that promote physical and mental health.

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Urban Density (persons per hectare)

Sprawl, defined:

Changes in residential development styles: large-lot housing

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Roots of Sprawl

Housing policies

Highway building vs. transit investment

Zoning policies

Lack of regional planning

Competition for tax revenue

Lifestyle choices

Las Vegas map and total population

Las Vegas, 1972

Las Vegas, 1986

Las Vegas, 1992

Problems with Sprawl

Environmental impacts

Health impacts

Automobile dependency

Land consumption & loss of farmland

Loss of a ”sense of place"

Costs to local government (infrastructure)

Social impacts and disinvestment in city centers

Environmental impacts of low-density land development -- aka Sprawl:

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Croton Watershed within the NYC Water Supply System

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Air Quality

Relationship between HH density and VMT:

Vehicle Miles Traveled (VMT) Per Capita, 1960-1995

Contribution of Highway Vehicles to Total U.S. Emissions of CO, NOx, and VOC, 1996

Air Quality Impacts

Pedestrian Safety

Urban form and physical activity

Urban form affects the relative convenience and viability of walking or biking for recreational, shopping, or work purposes – and thus influences the levels of physical activity patterns.

Only 30-40% of the American population engages in regular sustained exercise – another 30% are completely inactive!

Car dependency is associated with reduced walking or bicycling.

Slide 30

Obesity Trends* Among U.S. Adults
BRFSS, 1986

Obesity Trends* Among U.S. Adults
BRFSS, 1987

Obesity Trends* Among U.S. Adults
BRFSS, 1988

Obesity Trends* Among U.S. Adults
BRFSS, 1989

Obesity Trends* Among U.S. Adults
BRFSS, 1990

Obesity Trends* Among U.S. Adults
BRFSS, 1991

Obesity Trends* Among U.S. Adults
BRFSS, 1992

Obesity Trends* Among U.S. Adults
BRFSS, 1993

Obesity Trends* Among U.S. Adults
BRFSS, 1994

Obesity Trends* Among U.S. Adults
BRFSS, 1995

Obesity Trends* Among U.S. Adults
BRFSS, 1996

Obesity Trends* Among U.S. Adults
BRFSS, 1997

Obesity Trends* Among U.S. Adults
BRFSS, 1998

Obesity Trends* Among U.S. Adults
BRFSS, 1999

Obesity Trends* Among U.S. Adults
BRFSS, 2000

Obesity Trends* Among U.S. Adults
BRFSS, 2001

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Car Free City Center, 1996

Bicycles in Copenhagen

Public Spaces & Public Life

What Is an Urban Heat Island?

NY Regional
Temperature Trends

Slide 56

Heat-Related Mortality:
as Public Health Issue

* Direct heat casualties (NOAA)

- 1936-1975: 20,000 US deaths

- #1 US weather killer in 1995, 1998,

1999, 2000

- current US average ~220/yr

* Heat-related casualties (health researchers)

- NYC: 307/aver summer now, 460-1000 by 2050 with climate change

(Kalkstein & Greene, 1997)

Slide 58

Relevant Risk Factors for
Heat-Related Mortality

Elderly most susceptible to heat stress

Built-environment and social factors: A/C access, isolation

Early season heat waves worst

Slide 60

Cool City Project:
NYC Urban Heat Island
Mitigation & Research

Mitigation Measures:
Light-Colored Surfaces and Trees

Methodology: Energy and Air-Quality Analysis

Slide 64

Reflective Pavements are Cooler

Slide 66

Potential National Savings from Changing Roof Reflectivity

Objectives of A Cool City Project

Phase 1: Research on design and feasibility of residential roof-top demonstration projects; demographic analysis and identification of “hot” neighborhoods through thermal imagery; selection of methods for test projects

Phase 2: Implementation and documentation; measurement of energy consumption in demonstration buildings; preliminary assessment of air quality and public health impacts of UHI mitigation

Phase 3: Analysis of results and community outreach: Including an economic impact assessment of energy savings and benefits of cool roofing techniques, on an individual building and the community scale.

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As the human population and land development increases, more and more habitats are impacted. Today, we may be losing 30,000 species a year -- a rate much “faster than at any time since the last great extinction 65 million years ago that wiped out most of the dinosaurs. Estimated rate is 1,000 - 10,000 times above normal “background level.”

Native New Yorkers: Some endangered local species

Goals? Research to understand the interactions between land-use and public health priorities, and “smart growth” rather than sprawl:


	Joyce E. Rosenthal
	January 15, 2004
	Mailman School of Public Health
	Environmental Health Sciences Division


	Overview of some major environmental impacts of contemporary urbanization in the U.S.:

		Water quality
		Air quality
		Urban heat island effect
		Biodiversity loss


	In the US (and increasingly other nations), recent urbanization has become a process of “spreading out” – the vast expansion of metropolitan regions.

	The adverse ecological impacts that stem from low-density urbanization are associated with adverse public health impacts

	The public health and planning professions are challenged to work together to understand the impact of the built environment on health, and build communities that promote physical and mental health.


	Housing policies
	Highway building vs. transit investment
	Zoning policies
	Lack of regional planning
	Competition for tax revenue
	Lifestyle choices


	Environmental impacts
	Health impacts
	Automobile dependency
	Land consumption & loss of farmland
	Loss of a ”sense of place"
	Costs to local government (infrastructure)
	Social impacts and disinvestment in city centers


	Urban form affects the relative convenience and viability of walking or biking for recreational, shopping, or work purposes – and thus influences the levels of physical activity patterns.

	Only 30-40% of the American population engages in regular sustained exercise – another 30% are completely inactive!

	Car dependency is associated with reduced walking or bicycling.


	* Direct heat casualties (NOAA)
	- 1936-1975: 20,000 US deaths
	- #1 US weather killer in 1995, 1998,
	1999, 2000
	- current US average ~220/yr
	* Heat-related casualties (health researchers)
	- NYC: 307/aver summer now, 460-1000 by 2050 with climate change
	(Kalkstein & Greene, 1997)


	Elderly most susceptible to heat stress

	Built-environment and social factors: A/C access, isolation

	Early season heat waves worst


	Phase 1: Research on design and feasibility of residential roof-top demonstration projects; demographic analysis and identification of “hot” neighborhoods through thermal imagery; selection of methods for test projects

	Phase 2: Implementation and documentation; measurement of energy consumption in demonstration buildings; preliminary assessment of air quality and public health impacts of UHI mitigation

	Phase 3: Analysis of results and community outreach: Including an economic impact assessment of energy savings and benefits of cool roofing techniques, on an individual building and the community scale.