AIR POLLUTION - CONTINUED

The Clean Air Act requires EPA to set standards for 6 “criteria” air pollutants.

We have talked about two - particulates and ozone.

The other four are:

1. Carbon Monoxide, CO

2. Nitrogen Dioxide

3. Sulfur Dioxide

4. Lead

The two major sources of lead pollution have been vehicular emissions and industrial sources.

In the early 1970’s EPA started to reduce lead in gasoline.

In 1975, unleaded gasoline was introduced for cars with catalytic converters.

By 1995, all leaded gasoline was off the market except for aviation gasoline.

By 1999, lead in air had been reduced by 94%.

Most emissions are now from industrial sources - metal processing plants and lead acid battery facilities.

13% is from aviation gasoline.

High levels of lead are still found in localized areas.

It particularly affects infants and small children.

Low levels of lead can affect learning and lower IQ.

It can damage organs including the liver, kidneys, brain, nerves and heart.

Emissions from industrial sources have decreased only 6% since 1988.

The EPA standard for lead is 1.5 ug/m3 for a quarterly average.

CARBON MONOXIDE, CO, IS A COLORLESS, ODORLESS GAS. IT IS POISONOUS, AS IT BINDS HEMOGLOBIN AND PREVENTS OXYGEN TRANSPORT.

PEOPLE WITH HEART DISEASE ARE PARTICULARLY SUSCEPTIBLE, BUT EVEN HEALTHY PEOPLE ARE AT RISK FROM HIGHER LEVELS.

IT CAN ALSO DAMAGE THE CENTRAL NERVOUS SYSTEM.

MOST CO COMES FROM VEHICULAR EMISSIONS.

ABOUT 55% OF THE NATIONAL EMISSIONS COME FROM VEHICULAR EMISSIONS.

IN LARGE CITIES, THIS CAN AMOUNT TO 85 TO 95% OF THE EMISSIONS.

ATTEMPTS TO LIMIT EMISSIONS HAVE BEEN MADE THROUGH THE INTRODUCTION OF CATALYTIC CONVERTERS ON AUTOMOBILES AND TRUCKS, BUT THE NUMBER OF VEHICLES ON THE ROAD HAS DOUBLED OVER THE LAST 20 YEARS.

2 CO + O2 --> 2 CO2 (catalytic converter)

EPA CURRENT STANDARDS FOR CO ARE:

9 ppm (10 mg/m3) for an 8 hour average

35 ppm (40 mg/m3) for 1 hour

OXIDES OF NITROGEN, NOX, IS A COLLECTIVE TERM USED FOR SEVERAL COMPOUNDS FORMED WHEN OXYGEN AND NITROGEN REACT AT HIGH TEMPERATURES.

MOST ARE COLORLESS, BUT NO2, NITROGEN DIOXIDE, IS A REDISH BROWN.

YOU CAN SOMETIMES SEE THIS AS A BROWNISH HAZE OVER CITIES.

SOURCES INCLUDE AUTOMOBILES, ELECTRIC POWER PLANTS AND OTHER COMBUSTION SOURCES.

WHY ARE WE CONCERNED ABOUT NOX?

• contributes to formation of acid rain.• contributes to nutrient overload that deteriorates water quality.• contributes to atmospheric particles, that cause visibility impairment most noticeable in national parks.• reacts to form toxic chemicals.• contributes to global warming• involved in ground level ozone formation

CURRENT EPA STANDARDS FOR NITROGEN DIOXIDE:

0.053 ppm (100 µg/m3) Annual (Arithmetic Mean)

SULFUR DIOXIDE, SO2, IS FORMED WHEN FUELS CONTAINING SULFUR ARE BURNED OR METALS ARE EXTRACTED FROM ORES.

65% OF ALL SULFUR DIOXIDE COMES FROM ELECTRICAL UTILITIES BURNING COAL.

SULFUR IN GASOLINE AND DIESEL FUEL HAS BEEN GREATLY REDUCED OVER THE LAST SEVERAL YEARS.

SULFUR DIOXIDE IS A COLORLESS GAS WITH A VERY ACRID ODOR.

IT FORMS SULFURIC ACID IN THE AIR.

THE CAUSES OF CONCERN FOR SULFUR DIOXIDE ARE:

1. RESPIRATORY PROBLEMS

2. ACID RAIN

3. REDUCED VISIBILITY FROM SULFATE PARTICLES IN THE AIR

IT CAN BE TRANSPORTED OVER LONG DISTANCES.

EPA STANDARDS FOR SULFUR OXIDES:

0.03 ppm Annual Arithmetic Mean

0.14 ppm 24 Hour

EPA HAS ESTABLISHED AN AIR QUALITY INDEX FOR FIVE OF THE MAJOR AIR POLLUTANTS - OZONE, PARTICULATES, SULFUR DIOXIDE, OXIDES OF NITROGEN, AND CARBON MONOXIDE.

THIS IS A COLOR CODED HEALTH WARNING SCALE.

YOU WILL SEE THIS IN OUR AREA FOR OZONE AND PARTICULATES, ESPECIALLY IN THE SUMMER.

Air Quality Index (AQI) Values

Levels of Health Concerns

Meaning

0 - 50 Good Air pollution poses little or no risk

51 - 100 Moderate For some people there may be a moderate concern

101 - 150 Unhealthy for sensitive groups

General public is not likely to be affected

151 - 200 Unhealthy Everyone may begin to experience health effects

201 - 300 Very Unhealthy Health alert

> 300 Hazardous Emergency conditions