ENVR 301 Final

air pollution

any material added to the atmosphere (naturally or by humans) that harms living organisms, affects the climate, or impacts structures

Natural Sources of Air pollution

natural fires

volcanoes

sea spray

vegetation (generally not dangerous on their own)

bacterial metabolism

dust

pollen

primary pollutants

released directly from the source

secondary pollutants

modified to hazardous form after entering air and mixing with other environmental components

point source for air pollutants

“identifiable” source like a smokestack (generally stationary)

non-point source for air pollutants

mobile, small, or diffuse sources: gas stations, automobiles, cement plants, and country roads

mobile sources: vehicles

fugitive emissions

do not go through smokestack /pipe

ex: dust from human activities, fires

Primary Air Quality issues

particulate matter (rocks)

acid precipitation (SOx and NOx)

smog / ozone (NOx)

Toxins/irritants (Tox)

SOx pollutant forms

SO2, SO3, and SO4

NOx pollutant forms

NO and NO2

Criteria for air pollutants to be regulated by the EPA

1. 1. Harmful to human health or environment

2. 2. Come from numerous sources

HAPs

Hazardous Air Pollutants: pollutants that are toxic even in very small amounts

particulate matter

Aerosols (particulates/droplets) small enough to remain aloft in the air for a long period of time

• solid or liquid particulates in atmosphere that are larger than individual molecules

• 90% of all particulates are natural

  • salt spray, dust, and volcanoes

How are particulates in the atmosphere classified? What are the ranges?

classified by size

PM₄₄: μm or less (can remain suspended but generally don’t make it into the lungs)

PM₁₀: 10 μm or less (coarse); actually worry about this

• most natural PMs are larger than this

• generally direct result of combustion

• can make it into lungs

PM_2.5: 2.5 μm or less (fine); generally secondary pollutants

• SOx from coal fired power plants

• some can enter blood stream

what are add on pollution controls?

AKA end of stack/ end of pipe

reduces pollution after it is produced

Usually at release point

source reduction

change process so pollution is not produced

Types of add on controls and what they do

Fabric filters/baghouse: smaller the particles, smaller pore size = more energy it takes to push air through. Cheapest option

electrostatic precipitator: turn power off and particles drop to clean; more efficient; size of particle doesn’t matter; expensive; high power usage; only cleans charged particles

Wet scrubber: get lots of particles out of air; won’t clog; creates a lot of liquid waste

How to create source reductions

switch fuels

don’t burn coal

use alternatives

use less electricity

Industrial Smog

Product of coal burning/ common during industrial revolution

SO2 forms particulates, acid rain

CO: toxic gas

carbon particles: particle matter (ash and smoke)

greatly declined due to particle matter

Photochemical Smog

most concerning pollutants

Ingredients: NO, VOCs, O2, UV radiation

Production of Smog

Daily cycle

NO + VOC → NO2

NO2 + UV → NO + O (only starts when sun is out)

O + O2 → O3

NO2 + VOC → PAN etc

sources of VOCs in the atmosphere

organic chemicals that exist as gases

Natural: plants

Anthropogenic: mostly unburned hydrocarbons (fossil fuels)

How does acid rain form?

SO2 and NO react with O2 and H2O in atmosphere to form H2SO4 and HNO3

Sulfur in atmosphere

Natural:

• Evaporation of sea spray

• sulfate containing dust from arid regions

• volcanoes

• biogenic emissions: Hydrogen sulfide in soil

Anthropogenic:

• SO2 gas (majority) from combustion of fossil fuels

• smelting sulfide ores

Effects of atmospheric sulfur

SO2 toxic (lung damage) above 5ppm

Acid Rain

Effects of NOx in atmosphere

NOx gases are toxic (part of smog)

In precipitation it leads to:

• fertilization (Nitrogen) of terrestrial plants and aquatic environments; some plants are adapted to low nutrients (mountain tops)

pH of unpolluted rainwater

5.6

pH of acid rain

< 5.5 (typically between 4 and 5)

Acid rain terrestrial impacts

damages vegetation

Acidic soils release toxic metals (aluminum and mercury)

• aluminum drops pH as it leeches out

fertilization of nutrient poor soils can stress native plants

makes nutrient uptake more challenging

Acid rain aquatic impacts

simplifies food web

• - lose sensitive species like zooplankton, plants, and insects

Fish

• - eggs and fry die around pH of 5

• - adults die below pH of 5

• - enzymes denature and metabolic functions are disrupted

• - toxic metals become soluble: Aluminum gets stuck on gills and suffocates

Why does buffering capacity of soil and/or water matter for acid rain?

Calcium carbonate (CaCO3)

• limestone

• areas with lots of limestone: acid rain is neutralized

Clean air act types of pollutants

Criteria pollutants and Hazardous Air Pollutants

Criteria Pollutants

do harm and are more common (come from lots of sources

• not specifically listed out in the act

• PAM, O3, CO, SOx, NOx, Pb

established National Ambient Air Quality Standards

• Primary: human health

• Secondary: materials, environmental, aesthetic, comfort

Hazardous Air Pollutants

pollutants that may cause serious health effects or environment damage at low concentrations

• don’t have to come from numerous sources

• EPA created list of 189 HAPs and can add more

Air quality control regions

country is broken into air quality control regions (like a watershed for WQS’s but with no designated use)

• each region is either at attainment or non-attainment

meeting NAAQs

States create Implementation Plans (SIPs)

• sets limits on pollutants as they see fit → not on cars because on interstate travels

• primarily point sources (factories and power plants)

Federal Emissions Standards

set for “major sources” for all listed pollutants

Criteria Pollutants attainment Region: limits emissions from major new stationary sources

• Major = 100 tons per year of the pollutant

Criteria Pollutants non-attainment region: major new AND major existing stationary sources

• must offset pollution for major new sources

HAPS: limits ALL major sources regardless of location

• definition of major is lower

Federal Emissions Standards: mobile sources

Pb phased out of gasoline: 1975-1995

National fuel economy limits (minimums for mpg)

National emissions limits

• Required 90% reduction of CO, VOCs, NOx, from 1970 emissions levels (tailpipe)

The Greenhouse effect

warming of earth as greenhouse gases trap heat near earth’s surface

• we need some ggs to stay warm; makes earth livable

greenhouse gases

gases in atmosphere that trap heat (infrared light) near earth’s surface

Types of Greenhouse gases

H20: water vapor (least concern)

CO2: Carbon dioxide; fossil fuels

O3: ozone; fossil fuels

N2O: Nitrous oxide; fossil fuels

CH4: methane; fossil fuels

CFCs: chlorofluorocarbons; entirely man made

Enhanced Greenhouse effect

humans are elevating amounts of greenhouse gases in atmosphere; 33% CO2 increase since 1700s

• more heat is trapped by more greenhouse gases

How is relative heat trapping ability measured?

based on CO2 molecule

• CFCs have the highest heat trapping ability

weather

a description of physical conditions of the atmosphere at any given time

climate

a description of long-term patterns of average temperatures

albedo

measure of earth’s reflectivity

High albedo = more reflective (like snow)

low albedo = less reflective (like asphalt)

global warming potential

ability to trap heat and how long it stays in the atmosphere

impacts of climate change

global average temp has increased 1.2-1.3°C since 1900s

1.6-5.5 °C increase predicted by 2050; hoping to keep it below 1.5°C increase

Make an argument for 2 most important greenhouse gases to regulate

CO2 and CH4 are probably the easiest to argue for

Impacts of climate change on patterns

some areas are wetter or drier

more extreme weather

• increase in intensity, not in frequency

• Warmer ocean water feeds storms

melting glaciers and ice sheets

• 80% of earth’s glaciers are retreating

• rising sea levels from glacial water melt and thermal expansion

effects on biodiversity

current evidence of climate change

• sea level increase of another 2-3 feet by 2100 with only 2°C increase

• Storm surge: storm pushes water up; climate change brings up high tide making storm surges more dangerous

• Effects on biodiversity

What is biodiversity?

the variety of life that exists in an area

community (species) diversity, genetic diversity, and ecosystem diversity

species richness

total number of species in a community

species evenness

relative abundance of individuals within each species

genetic diversity

variation within a species, variation of alleles within a species

ecological/habitat diversity

variation in habitats, ecological interactions, ecological niches

• the more complex a habitat, the more species you will find

Landscape diversity

differences in variety and abundance of species in an area

Result of variation in

• abiotic factors (any disturbance or change) i.e. fires and floods

• geology/soils

• elevation/slope

Biodiversity from largest to smallest

Ecosystem → landscape → species → genetic

When is there high species diversity?

High productivity conditions (nutrients, water, temperature)

top predator is present (keystone predator)

there is an intermediate level of disturbance

intermediate disturbance hypothesis

high disturbance favors pioneer species

low disturbance favors climax species

**Best diversity in the middle**

gene

section of DNA that codes for a protein

allele

variations of a gene

trait

what gets expressed (phenotype)

result of environment and genes

proteins

make variety of traits that help determine structure and function

Where do new alleles come from?

Mutations: change in genetic code

• more likely to have a negative effect; often protein doesn’t function or is not adaptive

• others are neutral and don’t change the protein at all

• most mutations are recessive

allelic diversity

number of alleles available at a given gene

Heterozygosity

% of genes in individual that are heterozygous

• good to have options to better adapt for future

• less chance of expressing a mutation

measures of genetic diversity

allelic diversity and heterozygosity

Why are harmful recessive alleles not commonly expressed?

all organisms have multiple harmful alleles resulting from mutations

• if harmful it is selected against

• rare and recessive harmful alleles

instrumental value

A species has value if its existence or use benefits us

• aka utilitarian or anthropocentric

can calculate value based on dollars

intrinsic value

a species has value for its own sake

ecosystem services

ecological processes that make life possible: what biodiversity does for us

• provisioning

• regulating and supporting

• cultural

Benefits of biodiversity- food

200,000 + plant species

modern ag focuses on about 30

• 3 species fulfill 50% of global food needs (rice, wheat, corn)

Benefits of biodiversity- food security

genetic diversity for our current food supply

• more options to adapt, avoid inbreeding

• easier when we already have an allele

• cultivated varieties are highly selected for certain traits

• lose genetic variation, lost other beneficial qualities

How do wild populations benefit from genetic diversity

natural selection creates beneficial traits

• disease and parasite resistance

• better survival in the wild

• tolerance to adverse conditions

• plant breeders search wild populations for beneficial genes

  • maize saved the corn population

Biodiversity and Drugs/medicines

½ of medicines are derived from wild species

(see notes for examples)

• periwinkle

• Jarac snake

• Pacific Yew

Key parts of ecosystem

keystone species: species that extremely impact the shaping of its community (generally predators)

ecosystem engineers: species that alter physical environment of ecosystem (beavers and prairies dogs

ecosystem function

higher levels of biodiversity generally lead to greater ecosystem function

• nutrient cycling, primary productivity etc

sampling effect

when more species present more likely productive species present

complementarity effect

different species exploit different niches; more species means more niches filled

ecosystem stability

higher levels of biodiversity generally lead to greater ecosystem stability

• redundancy of function: more than 1 species doing the same jobs

• increase in function → increase in stability after certain species number is increased

extinct

completely gone

extirpated

no longer exists in a specific area

endemic

only exists in a specific area

Natural rate of extinction

1 spp/million/yr

extinction rate over the last 400 years

.01%/yr

Threats to Biodiversity

Habitat loss

Invasive species

Pollution

Overexploitation

Disease

Habitat destruction

loss due to conversion to different land use

most impacted by habitat destruction in US. Globally?

1. Wetlands: from being drained

2. grasslands: only 3% left

3. longleaf pine savannas: 1% left

Globally: half of the tropical forests are gone

Forest/ecosystem fragmentation results

smaller populations

dangerous migration: intraspecific competition

some species require multiple habitat types within their range

edge effects

• different species/different ecosystems

• other human impacts at the edge

  • air pollution, poaching, invasives, roadkill

common places to find fragmentation

wetlands (separated by drained areas)

rivers (dams)

grasslands (agriculture)

coral reefs (areas killed by acidification and sedimentation)

Habitat simplification

reduces ecological/ habitat diversity

same type of ecosystem

removing dead trees and logs from forests

forest monocultures

streams channelized: stream embeddedness

Invasive species

introduced species that causes damage to environment, human health, or economy

introduced species

species that has been introduced to a new habitat outside of its native habitat

Process of invasion

Introduction

establishment: dispersal

Invasive spread

Tens rule

10% of introduced become established

10% of established cause damage

• roughly 1% of introduced become invasive

How do invasive species intentionally move?

pet trade: fish, snakes, cats

agriculture/aquaculture

landscaping

How do invasive species unintentionally move?

lots of species come from Eurasia because we have similar climate and lots of trade

ballast water: water released by ships in ports

recreational

contaminants of shipped goods: emerald ash borer

Ecological Release

escape from factors that limit populations

• predators, parasites, disease

• food or space limitations

• environmental conditions are just right

Allelopathic chemicals

Allelopathy: inhibition of growth of competitor plants by release of chemicals that inhibit growth or germination