1Communicating air quality trade-offs

Module 6. Communicating Air Quality to the Public in

the Mid-Atlantic United Statesby K.G. Paterson, Ph.D., P.E. ©2007

www.mtu.edu

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Did You Know?For the counties of the Mid-Atlantic states (DC, DE,

NJ, MD, PA, VA, WV) there were, on average, about 4 days in 2005 with air quality designated unhealthy*….down from 8 days in 2000.**

* Total of AQI categories unhealthy for sensitive individuals and unhealthy** Based on three-year moving averages

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Course GoalsBy the end of this session, you will be able

to Know how the public is informed about air quality in

the Mid-Atlantic U.S. Define the AQI Know where to find current and forecasted air quality

conditions for your community

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Theory: AQIAQI = Air Quality Index

Allows easy communication of the air quality condition

• Developed to translate the real state of air quality into a relative state via an index

Uses: • Current conditions• Forecasted conditions

Range: 0 to 500Basis: criteria air pollutant measurements

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Theory: AQIThe number of air pollutants makes it

difficult to communicate the general condition of air quality in a community.

One way through this problem is to use a relative measure, or index, of air quality that is dependent on real measurements of the pollutants.

Advantages: Many numbers become oneEasier to communicate and understand

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Theory: AQIAQI methodology

Designed to communicate relative risk to public health from criteria pollutants

Criteria pollutant measurements used in the AQI estimation: O3 8-hr, O3 1-hr, PM2.5, PM10, CO, SO2, NO2

AQI above 100 means a criteria pollutant has exceeded its NAAQS

AQI Value Level of Health Concern

When AQI is in this range: …air quality conditions are:

0 - 50 Good

51 - 100 Moderate

101-150 Unhealthy for sensitive groups

151-200 Unhealthy

201-300 Very unhealthy

301-500 Hazardous

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Theory: AQIAQI methodology

Daily concentrations of each criteria pollutant (except lead) at a monitoring site are used to interpolate an AQI for that pollutant from the table below

Reported AQI is the highest of the individual pollutant AQIs

AQI O3 8-hr O3 1-hr PM2.5 PM10 NO2 SO2 CO

0 0 -- 0 0 -- 0 0

50 64 -- 15.4 54 -- 34 4.4

100 84 125 40.4 154 -- 144 9.4

200 124 204 150.4 254 0.65 304 15.4

300 374 404 250.4 424 1.24 604 30.4

400 504 0.504 350.4 504 1.64 804 40.4

500 -- 604 500.4 604 2.04 1004 50.4

ppb ppb ppm ppmppbµg/m3 µg/m3

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Application: AQI In the Mid-Atlantic U.S., AQI is usually set by ozone or

particulate. Both carry health implications at high AQI values.

AQI Value Health Concern

0 - 50 None

51 - 100 Sensitive people should limit prolonged outdoor exertion.

101-150 Active children and adults, and those with respiratory disease should limit prolonged outdoor activity.

151-200 Active children and adults, and those with respiratory disease should avoid prolonged outdoor activity; everyone else should limit prolonged outdoor activity.

201-300 Active children and adults, and those with respiratory disease should avoid all outdoor activity; everyone else should limit outdoor activity.

AQI Value Health Concern

0 - 50 None

51 - 100 Sensitive people should limit prolonged outdoor exertion.

101-150 People with heart or lung disease, older adults, and children should reduce prolonged outdoor activity.

151-200 People with heart or lung disease, older adults, and children should avoid prolonged outdoor activity. Everyone else should reduce prolonged outdoor activity.

201-300 People with heart or lung disease, older adults, and children should avoid all outdoor activity. Everyone else should avoid prolonged outdoor activity.

Ozone Particulate

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Theory: AQI CommunicationState and local authorities are required to

report AQI to the public in any community with 350,000 people or more.

If AQI exceeds 100, authorities will issue statements targeting affected individuals with suggested actions (Action Days)

AQI is routinely published through various media outlets.

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Application: AQI CommunicationAction Days

When AQI reaches (or predicted to reach) 100 or more

Meant to trigger two types of action• Protective measures that affected individuals should take

• Emission reduction measures that the public can take

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Analysis: AQI Communication

Question: In the summer, the AQI often exceeds 100 in the Mid-Atlantic U.S. due to enhanced ozone production. If an ozone Action Day is issued, what are some ways that the public could possibly reduce emissions that affect ozone levels?

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Application: AQI Communication

Based on the state’s AQI forecasts, EPA’s AirNow site is the most comprehensive source of regional AQI information

www.airnow.gov

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Application: AQI CommunicationState level authorities provide more local

AQI information.

Maryland Departmentof Environment:http://www.air-watch.net/ (also includes email alerts)

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Application: AQI Communication

Many newspapers are now reporting AQI on the Weather Page

Many local TV news stations report AQI during the Weather segment

Have you seen the AQI reported? Where?

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Theory: AQI Forecasting

Air quality monitoring data

Meteorological data Weather forecast models

Air quality models

Prediction: tomorrow’s weather

Prediction: tomorrow’s air quality

Today’s weather

Today’s air quality

National Weather Service

State Environmental Agencies

The state environmental regulatory agencies, NOAA and U.S. EPA collaborate to produce AQI forecasts with measurements and computer models

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Theory: AQI ForecastingWhile current prediction capabilities focus on AQI,

planned capabilities include specific pollutants

Current air quality alerts

10-year vision airquality alerts

Provide Next day warnings to big cities

Ozone and particulate guidance

Public products Daily AQI Hourly predictions of air pollutant concentrations

Coverage ~ 300 cities Nationwide

Pollutants forecasted AQI Ozone and particulate

Forecast period Next day, weekends Two days and beyond

Spatial resolution Community wide 2.5 km grid for entire U.S.

Temporal resolution Daily Hourly

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Application: AQI ForecastingBuilding to the 10-year vision

NOAA’s National Weather Service currently can provide ozone predictions for the eastern U.S., twice daily at a 12.5 km resolution.

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Analysis: AQI

Question: The AQI is a useful public communication tool, yet no index is perfect. How could it be improved?

Action: In a small group, discuss some of the weaknesses of the AQI and what it would take to minimize them.

Time: 5-10 minutes

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Further Learning

AirNow, the EPA’s website for current and forecasted AQI, http://www.airnow.gov

National Weather Service’s Air Quality Forecast site, http://www.nws.noaa.gov/aq/

A Guide to Mid-Atlantic Regional Air Quality, Appendix A: Health Effects of Air Pollution, pp. A3-A5. http://www.marama.org/reports/Guide-MidAtlantic_RegAQ_Final.pdf