Air Pollution in Los Air Pollution in Los Angeles: Angeles: History & OverviewHistory & Overview

Prof. Suzanne PaulsonProf. Suzanne PaulsonDepartment of Atmospheric and Department of Atmospheric and

Oceanic Sciences & Institute of Oceanic Sciences & Institute of Environment and SustainabilityEnvironment and Sustainability

Director, UCLA Center for Clean AirDirector, UCLA Center for Clean Air

Earliest written records of air pollution begin in Earliest written records of air pollution begin in at least 65 BC. at least 65 BC.

Mention of air pollution increased steadily as Mention of air pollution increased steadily as society developed.society developed.

The first air pollution regulation was probably The first air pollution regulation was probably issued in 1273, when King Edward I forbid coal issued in 1273, when King Edward I forbid coal burning near the White Castle.burning near the White Castle.

Air Pollution has a Long Air Pollution has a Long HistoryHistory

Mid 1600s John Evelyn: Mid 1600s John Evelyn: ““It is evident … that It is evident … that near half of the children that are near half of the children that are born and bred in London die under born and bred in London die under two years of age (a child born in a two years of age (a child born in a country village has an even chance country village has an even chance of living near forty years) ...the of living near forty years) ...the constant and unremitting poison is constant and unremitting poison is communicated by the foul air, communicated by the foul air, which, as the town grows still which, as the town grows still larger has made regular and steady larger has made regular and steady advances in its fatal influence.” advances in its fatal influence.”

Air Pollution Has Been Air Pollution Has Been Around for a Long TimeAround for a Long Time

1930: Meuse Valley, Belgium1930: Meuse Valley, Belgium, 63 dead, 600 injured. , 63 dead, 600 injured. TThe 15-mile valley trapped pollutants released by coke he 15-mile valley trapped pollutants released by coke ovens, steel mills, blast furnaces, zinc smelters, glass ovens, steel mills, blast furnaces, zinc smelters, glass factories, and sulfuric acid plants. factories, and sulfuric acid plants.

1948 1948 Donora, Pennsylvania, USA Donora, Pennsylvania, USA – This industrial – This industrial valley experienced a four-day air pollution episode valley experienced a four-day air pollution episode that resulted in 20 deaths, 600 ill, and 1400 seeking that resulted in 20 deaths, 600 ill, and 1400 seeking medical attention. Out of a population of 14,000. medical attention. Out of a population of 14,000.

Air Pollution Air Pollution Directly from SourcesDirectly from Sources Becomes Hard to IgnoreBecomes Hard to Ignore

These happened in Winter Time

What is an excess death? Who died?What is an excess death? Who died?

1952 London, five-day winter episode resulted 1952 London, five-day winter episode resulted in 12,000 excess deaths + many illnesses.in 12,000 excess deaths + many illnesses.

London, 1956, Similar winter meteorology leads to London, 1956, Similar winter meteorology leads to “only” 700 deaths. New regulations were already “only” 700 deaths. New regulations were already helping.helping.

New York City Thanksgiving 1966: 168 people died New York City Thanksgiving 1966: 168 people died during a during a strong temperature inversion.strong temperature inversion.

Between the Early 1950’s and Now, Many Between the Early 1950’s and Now, Many More ‘Air Pollution Disasters’ have More ‘Air Pollution Disasters’ have Happened, but Most Have Been Milder.Happened, but Most Have Been Milder.

We’ll discuss temperature inversions later

It happens in summer, not winter. It happens in summer, not winter. Began in the 1940s. Began in the 1940s. Low visibility from summer time smog is blamed for Low visibility from summer time smog is blamed for 2000 car accidents in 2000 car accidents in one dayone day 1954. 1954.

Los Angeles Smog: a Whole Los Angeles Smog: a Whole New StoryNew Story

Los Angeles had lots of agriculture, and crop yields were dropping fast.

Los Angeles smog is similar to winter smogs, but it is whiter, and contains high levels of ozone.

Particles: Particles: Size MattersSize Matters

PM10 PM10 = All particles smaller than 10 microns in = All particles smaller than 10 microns in Diameter. Mostly from stuff being ground up.Diameter. Mostly from stuff being ground up.PM2.5PM2.5 = All particles smaller than 2.5 microns in = All particles smaller than 2.5 microns in Diameter. Mostly from combustion.Diameter. Mostly from combustion.

TSP: Total Suspended Particulate = Everything you can catch on a filter

Where Particles Deposit Depends on Their Where Particles Deposit Depends on Their SizeSize

Movememt of ultrafine particles along sensory neurons (neurodegeneration)

Transfer of ultrafines to circulatory system

Coarse Particles, > 2.5 micronsDeposit in upper airways, where they are removed by cilia but likely exacerbate Asthma

0.1 micron < Fine particles < 2.5 microns Penetrate into Alveoli. Body cannot remove them.

Old Federal Standard: PM 10 below 150 Old Federal Standard: PM 10 below 150 g/mg/m3 3 for 24 for 24 hrs and 50 hrs and 50 g/mg/m3 3 annual average. annual average.

Newest Federal Standard: PM 2.5 below 65 Newest Federal Standard: PM 2.5 below 65 g/mg/m3 3

for 24 hrs and 12 for 24 hrs and 12 g/mg/m3 3 annual average.annual average.

PM2.5 particles scatter light very efficiently, especially PM2.5 particles scatter light very efficiently, especially particles that are between 0.2 and 1 microns particles that are between 0.2 and 1 microns

Small Particles are visible!Small Particles are visible!

{{

Air Pollutant Types and Air Pollutant Types and SourcesSources

Wintertime vs. Summertime SmogWintertime vs. Summertime Smog

PrimaryPrimary pollutants are emitted directly from pollutants are emitted directly from sources. sources. Particulate Matter (PM), Carbon monoxide, Lead, Particulate Matter (PM), Carbon monoxide, Lead,

sulfur dioxide, nitrogen dioxide, many “air toxics” sulfur dioxide, nitrogen dioxide, many “air toxics” London, Beijing, California’s central valley, New London, Beijing, California’s central valley, New

DelhiDelhi

SecondarySecondary pollutants form in the atmosphere from pollutants form in the atmosphere from chemical transformations of the primary chemical transformations of the primary pollutants. pollutants. Ozone, particulate matter, some nitrogen Ozone, particulate matter, some nitrogen

dioxide, some air toxicsdioxide, some air toxics Los Angeles, Mexico City, Santiago ChileLos Angeles, Mexico City, Santiago Chile

Types of Air PollutionTypes of Air Pollution

--Pollutants for which there are Pollutants for which there are national national ambient air quality standards ambient air quality standards (NAAQS) In (NAAQS) In the US the criteria pollutants are:the US the criteria pollutants are:

Carbon monoxideCarbon monoxide CO CO LeadLead PbPb Oxides of nitrogenOxides of nitrogen NONOxx

OzoneOzone OO33

Sulfur dioxideSulfur dioxide SOSO22

Particulate matterParticulate matter PM10/PM2.5PM10/PM2.5

Criteria Pollutants

fuel + Air fuel + Air Carbon dioxide + water +Carbon dioxide + water +VOCs + NOVOCs + NOxx + particulate + particulate matter (PM), Carbon matter (PM), Carbon

Monoxide Monoxide (CO), SO(CO), SO22, Pb, toxic , Pb, toxic organics as organics as benzene, benzene, polyaromatic polyaromatic hydrocarbons, acrolein etc.hydrocarbons, acrolein etc.

Combustion makes more Combustion makes more than just COthan just CO22 and water and water

NONOxx:: All combustion sources All combustion sources NO NOxx Vehicles, Industry, Biomass Burning Vehicles, Industry, Biomass Burning

NONOxx is is essentially allessentially all from human from human activitiesactivities

HydrocarbonsHydrocarbons (HCs or VOCs or ROGs) (HCs or VOCs or ROGs) come from many sourcescome from many sources::

Vehicles (both the engine and Vehicles (both the engine and leaking unburned fuel)leaking unburned fuel)

Industrial and Residential: solvents, Industrial and Residential: solvents, paints & coatings, cleaners paints & coatings, cleaners

TreesTrees

Pollutant Sources: NOPollutant Sources: NOxx from from Combustion, VOCs from EverythingCombustion, VOCs from Everything

ParticlesParticles:: All combustion sources All combustion sources fine fine

and ultrafine particles and ultrafine particles Vehicles, Industry, Biomass Vehicles, Industry, Biomass

Burning Burning Industrial processes Industrial processes dust dust

and fumesand fumes Roadways, agriculture, deserts Roadways, agriculture, deserts

and desertification and desertification dust dust

Small particles (PM2.5 and PM0.1) are Small particles (PM2.5 and PM0.1) are from combustion or smog chemistry, from combustion or smog chemistry, large particles (PM10) are from large particles (PM10) are from mechanical grinding. mechanical grinding.

Formation of Los Angeles Formation of Los Angeles Style SmogStyle Smog

{{

The “Air Quality Index” (AQI) is defined The “Air Quality Index” (AQI) is defined as the percent of the Ambient Air as the percent of the Ambient Air Quality Standard (Usually National or Quality Standard (Usually National or World Health Organization’s)World Health Organization’s)

Formation of Smog- LA StyleFormation of Smog- LA Style

VOCs + NOVOCs + NOxx + + sunlight sunlight

photochemical smog photochemical smog (= (= OO3 3 , more particles , more particles

and other nasty and other nasty compoundscompounds))

VOCs VOC reaction products Ozone

The Daily Smog Cycle

CO is emitted directly from sources—no photochemistry, so it shows where most of the pollution sources are.

http://www.epa.gov/airnow/mapselect.html

http://www.airnow.gov/index.cfm?action=airnow.mapsarchivedetail&domainid=33&mapdate=20150728&tab=1

OZONE IN LOS ANGELES 1976-2014(There is a new ozone standard 12/2014: 70 ppb over 8 hrs)

PM 2.5

2002

2013

Air Pollution Air Pollution Then and NowThen and Now

1950’s1950’s NowNow PopulationPopulation 4.8 Million4.8 Million 16 Million 16 Million VehiclesVehicles 2.3 Million2.3 Million 11 Million 11 Million Peak Ozone Levels Peak Ozone Levels 680 ppb680 ppb 160 ppb 160 ppb Peak CO Levels Peak CO Levels 33 ppm33 ppm 4.7 ppm 4.7 ppm Peak NOPeak NO22 Levels Levels 690 ppb690 ppb 110 ppb 110 ppb Peak PM10 Levels Peak PM10 Levels 649 649 g/mg/m33 84 84 g/mg/m33

Peak PM2.5 Levels Peak PM2.5 Levels unknownunknown 65 65 g/mg/m33 75+ % Reduction of most pollutants!75+ % Reduction of most pollutants!Emissions have been reduced by more than 90%.Emissions have been reduced by more than 90%.

Schedule for meeting Federal Schedule for meeting Federal Air Quality StandardsAir Quality Standards

PollutantPollutant Target AttainmentTarget Attainment StatusStatus

ScheduleSchedule

CO: CO: 20002000 Actually met in Actually met in 20032003

PM10: PM10: 20062006 Actually met in 2010.Actually met in 2010.

Ozone-1-hr: Ozone-1-hr: waswas 2010 2010 Current target: 2022 Current target: 2022

PM2.5: PM2.5: 2018 2018 Maybe. Maybe.

8-Hr Ozone: 8-Hr Ozone: 2040?2040?

{{

Why some places have good Why some places have good air quality and others have air quality and others have bad air qualitybad air quality

Large amounts of pollution emissions. Cars, Large amounts of pollution emissions. Cars, industry, trucks, dust, agricultural burning, industry, trucks, dust, agricultural burning, wildfires…. wildfires….

Summer time smog requires sunlightSummer time smog requires sunlight

Low winds, temperature inversions.Low winds, temperature inversions. ““the solution to pollution is dilution”the solution to pollution is dilution”

Ingredients for poor air Ingredients for poor air qualityquality

Temperature InversionsTemperature Inversions

Wind flow in Los Angeles on typical (smoggy) days

Daily smog cycle in Los Angeles

Daytime mixing height limitations in Los Angeles

If the local temperature profile matches the normal rate of cooling for air parcels, there is no reason for parcels to prefer one height or location over another. The parcels can move around freely.

Pretend an air parcel is a contained in a weightless, elastic balloon containing a fixed amount of air. As the balloon’s altitude increases, the balloon will expand, and its air temperature will cool.

The atmosphere cools with increasing altitude, at an average of 6.5 degrees C per km.

Temperature profile of the lower atmosphereWhen it is well mixed

An inversion is a temperature profile that is constant or increasing with increasing height. This puts warm air over cool air, and stops upward mixing completely.

Temperature profile of the lower atmosphereWhen when mixing is poor

Causes of InversionsCauses of Inversions

                                                                                                                                            

1. Radiation Inversions: 1. Radiation Inversions: These are common These are common almost everywherealmost everywhere

The average atmosphere is The average atmosphere is warmest near the surface, but warmest near the surface, but locally the temperature profile can locally the temperature profile can be different.be different.

After sunset, the earth's surface After sunset, the earth's surface cools and radiates energy, so the air cools and radiates energy, so the air closest to the surface cools before closest to the surface cools before air higher up.air higher up.

An An inversioninversion forms - air near surface forms - air near surface cooler and denser than the air cooler and denser than the air above it. These inversions are most above it. These inversions are most common and strongest on winter common and strongest on winter mornings.mornings.

Diurnal evolution of the nocturnal surface inversion and daytime mixed layer.

Unlike the daytime “mixed layer”, the nighttime surface layer is very poorly mixed. Pollutants stay at the level where they were emitted, and move laterally bad pollution

In the evening and night, the ground surface cools. If the ground is not flat, the cooled air will flow down hill, and accumulate in the valley. The air will be trapped there until the sun comes out and warms up the ground.

Sometimes the cold weather persists for days, and pollution accumulates day after day. This is usually the reason extreme pollution events (London, Beijing, Denora) happen when they do.

Radiation Inversions in Valleys

Measuring plumes from freeways in the Measuring plumes from freeways in the early morning: Weak winds from the north early morning: Weak winds from the north of the freeway dominate in the early AM. of the freeway dominate in the early AM. (They reverse during the day)(They reverse during the day)

_________________________________________________

The Imprint of the Freeway is Many Times The Imprint of the Freeway is Many Times Larger During Just Before Sunrise Larger During Just Before Sunrise Compared to DaytimeCompared to Daytime

0

0.2

0.4

0.6

0.8

1

-1500 -1000 -500 0 500 1000 1500 2000 2500 3000

Distance from Freeway (m)

Rel

ativ

e U

FP

Con

cent

ratio

n

Pre-Sunrise: WinterPre-Sunrise: SummerDaytime (Zhu et al 2002b)

DownwindUpwind

Freeway

Pico

Pearl

Olympic

Ocean ParkDonald Douglas

Palms

Kansas

_________________________________________________

High pressure systems produce large areas of subsiding air. As the air descends, it is compressed and heats up. Subsidence inversions are large enough to cover entire regions, and persist for days to weeks. They are common in many places, especially Los Angeles.

2. The Trouble with Beautiful Weather: Subsidence Inversions

When the weather is fair, there is almost always an upper level inversion

On sunny days, the land surface heats and causes air to rise. Marine air is pulled in to fill the void, and the marine air is cooler, resulting in cold air under air warm air.

3. Marine Inversions

Inversion Types – Los Angeles has Four!Inversion Types – Los Angeles has Four!1) Radiation inversions.1) Radiation inversions.2) Subsidence inversions.2) Subsidence inversions.3) Cool marine air undercuts warm air over land, resulting 3) Cool marine air undercuts warm air over land, resulting

in a in a marine inversionmarine inversion. . 4) Flow of air from a high plateau descends and warms by 4) Flow of air from a high plateau descends and warms by

compression, creating a cap above a cooler air mass in compression, creating a cap above a cooler air mass in a basin below the highlands. a basin below the highlands.

The mixing height changes with season; it is lowest in the winter

Cleaning up the airCleaning up the air

Regulatory AuthorityRegulatory Authority South California Air Quality Management District South California Air Quality Management District

(SCAQMD): (SCAQMD): Local industrial and commercial sources.Local industrial and commercial sources. California Air Resources Board (CARB): California Air Resources Board (CARB): passenger passenger

vehicles, consumer products, local diesel vehicles & vehicles, consumer products, local diesel vehicles & construction equipment.construction equipment.

Federal: Federal: Interstate sources; planes, trains, interstate Interstate sources; planes, trains, interstate trucks & bussestrucks & busses

InternationalInternational: Large marine vessels and international : Large marine vessels and international airlinersairliners

Major Steps to Cleaning Major Steps to Cleaning up Air in LAup Air in LA

State Actions: Mobile Sources State Actions: Mobile Sources

Because California has such a large economy, if it Because California has such a large economy, if it requires lower emissions from cars than the USEPA, requires lower emissions from cars than the USEPA, automakers cannot ignore it. In the end, California has automakers cannot ignore it. In the end, California has almost always succeeded in setting the regulations it almost always succeeded in setting the regulations it wants.wants.

19611961 The first automotive emissions control The first automotive emissions control technology in the nation, Positive Crankcase technology in the nation, Positive Crankcase Ventilation, is mandated. Ventilation, is mandated.

19781978 Mandate 3-way catalysts control hydrocarbons, Mandate 3-way catalysts control hydrocarbons, nitrogen oxides, and carbon monoxide.nitrogen oxides, and carbon monoxide.

State Actions: Mobile Sources State Actions: Mobile Sources

1984 1984 first smog check program; this will be first smog check program; this will be updated repeatedly. updated repeatedly.

1990-current 1990-current Mandated improvements to the Mandated improvements to the durabilitydurability of emissions control of emissions control

1990-current 1990-current Mandate low and Zero Emission Mandate low and Zero Emission Vehicles. Vehicles.

Vehicles on the road today are 100 to 400 times Vehicles on the road today are 100 to 400 times cleaner than vehicles in the 1960s. And some cleaner than vehicles in the 1960s. And some vehicles have zero emissions.vehicles have zero emissions.

State Actions: GasolineState Actions: Gasoline

Clean fuels are probably the closest we can get to a “silver Clean fuels are probably the closest we can get to a “silver bullet”. Clean the gasoline, and all of the cars use it right bullet”. Clean the gasoline, and all of the cars use it right away. away.

1976, 19921976, 1992 CARB limits then removes lead. CARB limits then removes lead. 1992 & 19961992 & 1996 Phase I & Phase II California Cleaner Burning Phase I & Phase II California Cleaner Burning

Gasoline introduced. Reduces volatility, reactivity and Gasoline introduced. Reduces volatility, reactivity and toxicity of gasoline, and made major improvements to 1 hr toxicity of gasoline, and made major improvements to 1 hr ozone concentrations.ozone concentrations.

Winter 1992, Winter 1992, ARB requires addition of oxygenates to cut CO ARB requires addition of oxygenates to cut CO emissions by 10%. (MTBE was added, to be replaced later by emissions by 10%. (MTBE was added, to be replaced later by ethanol).ethanol).

State Actions: Fuel Delivery & State Actions: Fuel Delivery & Diesel fuelDiesel fuel

1972, 1976, 1991 1972, 1976, 1991 Vapor recovery at gas stations in Vapor recovery at gas stations in San Diego, Polluted areas, and then the whole stateSan Diego, Polluted areas, and then the whole state19931993 First California Diesel Fuel comes to market. First California Diesel Fuel comes to market. Lowers diesel particulate emissions by 14 tons/day, Lowers diesel particulate emissions by 14 tons/day, sulfur dioxide by 80 tons/day and nitrogen oxides by sulfur dioxide by 80 tons/day and nitrogen oxides by 70 tons/day emissions. 70 tons/day emissions. 20062006 Ultra-low sulfur diesel is introduced Ultra-low sulfur diesel is introduced

State State & Local & Local Actions: Consumer Actions: Consumer Products, Small EnginesProducts, Small Engines California has many reformulated products. California has many reformulated products.

These include These include household cleaners, insect sprays, household cleaners, insect sprays, bbq lighter fluid, and paintsbbq lighter fluid, and paints. .

CARB andCARB and SCAQMD SCAQMD have implemented multiple have implemented multiple programs programs for small engines such as gardening for small engines such as gardening equipment and small boatsequipment and small boats..

CARB and CARB and SCAQMDSCAQMD worked with other worked with other stakeholders to clean up stakeholders to clean up the ports: clean trucks, the ports: clean trucks, port and dock electrificationport and dock electrification

Federal (National) Actions Federal (National) Actions

1963 1963 First Federal Clean Air Act. First Federal Clean Air Act. The act has been The act has been amended many times, often tightening National Ambient amended many times, often tightening National Ambient Air Quality Standards (NAAQS)Air Quality Standards (NAAQS)

1967 1967 New federal Clean Air Act New federal Clean Air Act gives California special gives California special authority to set its own emissions standards for new authority to set its own emissions standards for new vehicles.vehicles.

1970 U.S. Environmental Protection Agency (U.S. EPA) 1970 U.S. Environmental Protection Agency (U.S. EPA) created. created.

2000’s2000’s USEPA works with CARB to create clean trucks USEPA works with CARB to create clean trucks program, finally addressing this major source of pollution.program, finally addressing this major source of pollution.

Socio-Political ClimateSocio-Political Climate

1940’s, 1950’s, 1960’s there were many protests related 1940’s, 1950’s, 1960’s there were many protests related to air quality in Los Angelesto air quality in Los Angeles

Rachel Carson writes Rachel Carson writes Silent SpringSilent Spring 1940s-1980s1940s-1980s Candidates for Governor all went to visit the Candidates for Governor all went to visit the

Universities to discuss air pollution control.Universities to discuss air pollution control. 1970 1970 First Earth Day. Earth Day is still observed every First Earth Day. Earth Day is still observed every

April.April. 1973 1973 OPEC Oil Embargo raises the price of oil. Market OPEC Oil Embargo raises the price of oil. Market

forces result in more fuel efficient automobiles and forces result in more fuel efficient automobiles and industry, and corresponding lower air emissions.industry, and corresponding lower air emissions.

1993 1993 adopts Regional Clean Air Incentives Market adopts Regional Clean Air Incentives Market (RECLAIM) program for NOx and SOx. VOCs were (RECLAIM) program for NOx and SOx. VOCs were considered, but VOCs are far more complicated. considered, but VOCs are far more complicated.

Runs the extensive air quality monitoring network; handles Runs the extensive air quality monitoring network; handles permitting for point and area sourcespermitting for point and area sources

..Holds public hearings, ~150 educational events each yearHolds public hearings, ~150 educational events each year Agencies (especially Agencies (especially SCAQMDSCAQMD) perform special studies for ) perform special studies for

communities when needed. communities when needed.

Local: Local: SCAQMD SCAQMD Control of stationary Control of stationary sources, monitoring, planning, educationsources, monitoring, planning, education

California’s Regulatory Approach: California’s Regulatory Approach: IndustryIndustry

California agencies (CARB and SCAQMD) expect California agencies (CARB and SCAQMD) expect best available control technologies best available control technologies at a at a minimum. minimum.

CARB often works to set policies that are CARB often works to set policies that are technology forcingtechnology forcing. .

Policies are developed with input from Policies are developed with input from stakeholders, including the industry to be stakeholders, including the industry to be regulated, but also representatives of NGOs, the regulated, but also representatives of NGOs, the public public and other interested parties.and other interested parties.

California has been sued repeatedly for its California has been sued repeatedly for its policies. This typically delays implementation.policies. This typically delays implementation.

New Policies in the mid ‘10sNew Policies in the mid ‘10sMost of the low hanging fruit has been picked. Also Most of the low hanging fruit has been picked. Also emphasis on climate – air quality co-benefitsemphasis on climate – air quality co-benefits More improvements in engine design and emissions More improvements in engine design and emissions

control durability.control durability. Tighter requirements for consumer productsTighter requirements for consumer products Require new glass in autos to keep them coolerRequire new glass in autos to keep them cooler Cash for clunkers, trade in programs for gardening Cash for clunkers, trade in programs for gardening

equipmentequipment ““Mode shifting” to encourage use of Mode shifting” to encourage use of

transit/walking/cyclingtransit/walking/cycling Further improvements in the ports and goods shipmentFurther improvements in the ports and goods shipment Emphasis on growing the zero emissions market, Emphasis on growing the zero emissions market,

including Hydrogen, electric vehicles, fuel cell vehiclesincluding Hydrogen, electric vehicles, fuel cell vehicles

Los Angeles still has a very long way to go Los Angeles still has a very long way to go to control ozoneto control ozone With existing

controls

Thank youThank you