EPA Precursor Gas Training Workshop Nealson Watkins & Dennis Mikel EPA - Office of Air Quality,...

EPA Precursor Gas Training Workshop

Nealson Watkins & Dennis Mikel EPA - Office of Air Quality, Planning and Standards

Technical Support of NCore Implementation:

Meteorological Requirements


Outline• Introduction• NCore Requirements• Sensors (Calibrations and QA issues)

– Siting– Sonic Anemometers– Equipment miniaturization

• Data Handling Issues– Data Acquisition Systems

• Overview of the revision of the QA Handbook, Volume IV: Meteorological Measurements


• Currently only required for PAMS sites (~ 92 sites)• However, many S/L/Ts measuring even without a requirement

– Reporting to AQS and/or AIRNow– Approximately 31 users submitting to AIRNow-Tech

AIRNow-Tech Navigator illustrating PM2.5 and Wind barbs

The State of State, Local, and Tribal Meteorological Monitoring


Met Data Reported to AQS*

*Sites shown do not necessarily report more than one parameter

As of1/22/07


What is meteorological data supposed to do for us? – Used as supportive data at multi-pollutant sites (re:

NCore)

And who wants all this supportive meteorological data?– Modelers– Data Analysts– Forecasters


What are some known S/L/T issues with reporting meteorological data?

Primary Issue:

• Many State/Local agencies are hesitant to use the meteorological data they collect because of uncertainty in data quality.

• Several State/Local agencies have trouble accessing meteorological data both from their own agency and from neighboring agencies.

• Some traditional meteorological monitoring methods (e.g. siting criteria) are not appropriate for air quality applications.

Possible Solution:

• Quality Assurance (QA) requirements at NCore multi-pollutant sites to promote better data quality.

• Enhance EPA’s databases (e.g. AIRNow and AQS) to improve their capability for storing and sharing meteorological data.

• Create measurement methods specific to meteorological monitoring for air quality management. Specifically, investigate ways to appropriately use met data from a site that may not be “perfect.”


So why all the attention on meteorological data that’s currently NOT required??

NCorNCoree


NCore Design Criteria• 40 CFR 58 Appendix D.3.b states, “The NCore

sites must measure, at a minimum, PM2.5, ….wind speed, wind direction, relative humidity and ambient temperature.”

• Additional parameters may include: – Solar Radiation– Precipitation– Barometric Pressure

Wind data in vector format!


NOAA vs. S/L/T Met Data• S/L/Ts provide hourly averaged data

– NOAA data is a 2 minute average taken 10 to 20 minutes before the top of the hour

• S/L/T wind data can be vector averaged!– NOAA wind data is scalar only– Vector data is needed to follow (model) air parcel

movements• S/L/T met. data will be co-located with air

pollution data• S/L/T data may represent multiple siting scales

– Regional, Neighborhood, Middle, & Microscale


Tools of the trade…

• Wind speed

• Wind direction

• Ambient Temperature

• Relative humidity


Additional Instrumentation

• Barometric Pressure

• Solar Radiation

• Precipitation

*EPA’s reference to certain product types or brand-names does not translate into endorsement.


• Siting is very critical, as it directly determines what the data represent

• The Issue:Siting for air pollution monitoring doesn’t always allow for ideal siting for meteorological monitoring

• The Solution:Focus on NCore sites, and reference the revised QA Handbook for non-NCore sites.

Siting Issues


Ideal Siting Criteria

MeasurementDistance

from Obstruction

Distance Above Ground

Recommended Group Cover

Comments

Wind Speed/Direction

10x the height of the obstruction

10 meters Grass or gravel The standard exposure of the wind instruments overlevel, open terrain is 10 meters above ground11

Temperature/ Dew Point

1.5x the tower diameter

1.25 to 2 meters Non-irrigated or un-watered short grass, or natural earth

The surface should not be concrete or asphalt or oil-soaked. Reflection from these surfaces may affect the performance of the sensor.

Vertical Temperature Difference

1.5x the tower diameter

2 meters and 10 meters

Non-irrigated or un-watered short grass, or natural earth

The surface should not be concrete or asphalt or oil-soaked. Reflection from these surfaces may affect the performance of the sensor.

Solar Radiation 2 meters 2 to 10 meters No requirements Sensor should be free from obstructions above the plain of the sensor. It should be located so that shadows will not cast on the device.

Barometric pressure

1 meter 1 to 10 meters No requirements The location should have uniform, constant temperature, shielded from the sun, away from drafts or heaters

Precipitation 2x to 4x the obstruction height

30 cm, minimum Natural vegetation or gravel

Asphalt or concrete should be avoided to avoid splashing the gage. The gage should be high enough to avoid it being covered by snow.

Note: More details on siting and exposure are available in the individual sections of the QA Handbook. Please see the installation section of each chapter for more information.


Siting issues with towers

• Section 2.4 of QA Handbook is updated. • Ideally, NCore sites will follow NWS

type setup• The remaining majority of sites likely

will have more relaxed criterion Remember:

EPA can only make recommendations!


QA Issues• In most instances, Met data are collected for:

– Forecasting– Modeling – Data Analysis– Public consumption

• Since Met data is supportive, generally, DQOs don’t need to be generated.

Without DQOs, how do we get the Measurement Quality Objectives (MQOs)?

The answer: QA Handbook has tables of MQOs for programs that recommend or require Met data

Suggested NCore Measurement Quality Objectives

Measurement MethodReporting

units

RequiredOperating

RangeResolution

MinimumSample

Frequency

Raw DataCollectionFrequency

Completeness

(Required)

Ambient Temperature

Thermistor ºC -30 – 50 0.1 Hourly 1 minute 75%

Relative Humidity Psychrometer/Hygrometer

% 0 – 100 0.5 Hourly 1 minute 75%

Wind Speed Cup, prop or sonic

anemometer

m/s 0.5 – 50.0 0.1 Hourly 1 minute 75%

Wind Direction Vane or sonic anemometer

Degrees 0 – 360 (540)3 1.0 Hourly 1 minute 75%

Vector DataWind Speed

Wind Direction

DAS Calculations

m/sdegrees

0 – 50.00 – 360

0.11.0

Hourly 1 minute1 minute

75%

(Optional)

Solar Radiation Pyranometer Watts/m2 0 – 1100 10 Hourly 1 minute 75%

Precipitation Tipping Bucket mm/hr 0 – 25 mm/hr 0.2 mm Hourly 1 minute 75%

Barometric Pressure

Aneroid Barometer

mb 600 – 1100 0.5 Hourly 1 minute 75%

Measurement

Calibration Accuracy

TypeAcceptance

CriteriaFrequency Type

Acceptance Criteria

Frequency

Ambient Temperature

3 pt. Water Bath with NIST-traceable thermistor or thermometer

±0.5 ºC Quarterly 3 pt. Water Bath With NIST-traceable thermistor or Thermometer

±0.5 ºC Semi-Annually

Relative Humidity NIST-traceable Psychrometer or standards solution

±7% RH Quarterly NIST-traceable Psychrometer or standards solution

±7% RH Semi-Annually

Wind Speed NIST-traceable Synchronous Motor

±0.25m/s ≤5m/s; 5%>2m/s not to exceed 2.5m/s

Quarterly NIST-traceable Synchronous Motor

0.25m/s ≤5m/s; 5%>2m/s not to exceed 2.5m/s

Semi-Annually

Wind Direction Solar Noon, GPS Magnetic Compass

±5 degrees; includes orientation error

Quarterly Solar Noon, GPS or Magnetic Compass

±5 degrees; includes orientation error

Semi-Annually

Solar Radiation NIST-traceable Pyranometer

±5% of mean observed interval

Quarterly NIST-traceable Pyranometer

±5% of mean observed interval

Semi-Annually

Barometric Pressure

NIST-traceable Aneroid Barometer

±3 mb Quarterly NIST-traceable Aneroid Barometer

±3 mb Semi-Annually

Precipitation Separatory funnel and graduated cylinder

±10% of input volume

Quarterly Separatory funnel and graduated cylinder

±10% of input volume

Semi-Annually

Suggested NCore Calibration/Audit Recommendations


Sonic Anemometers• “Sonics” are a relatively new to our market• Use time-of-flight of sonic impulses to determine wind

speed and direction• Pros:

– High Sensitivity– No moving parts

• Cons:– Harder to QA

and calibrate in

the field


Sonic Data Issues• Electrical hiccups can occur• Data interpretation can be slightly different

Example1: When windsgo to calm conditions, what happens to the wind direction?• Do we want to emulate old systems for data continuity purposes?

Example2: How much of an issue is eddy turbulence? • Either “Self” produced or from nearby obstacle?


Miniaturization

• Several vendors now have miniature weather stations available– Climatronics & Vaisala

• OAQPS is obtaining one of each unit for evaluation purposes

• Vendors claim accuracy and resolution metrics within those in the suggested NCore MQO table

• Could be an answer for some QA issues associated with sonic and other methods (think co-location)


Miniature Met Stations

Climatronics• Includes:

– WS, WD, T, RH and

self-orients to North

Vaisala• Includes:

– WS,WD, T, RH and precipitation


Wind DataScalar Data vs. Vector Data

• Overall difference is more apparent at lower wind speeds– Scalar: using arithmetic average– Vector: either directly obtain or derive orthogonal components

from scalar values

• In the case of wind speed, vector-averaged speeds are never larger than the scalar-averaged values and generally are lower

• Example: 10 minute total average– North wind at 5 m/s for 5 minutes– South wind at 5 m/s for 5 minutes

Scalar average: 5 m/s & Easterly (90°) headingVector average: 0 m/s & No net movement


Data Handling


Data Handling• Once we’re sited and running, it’s time to

review and move the data• Many sensors providing analog data to a

translator (esp. wind data)• Translators typically can output

digitally or analog • Vector averaging requires conversion

from scalar (by translator or data acquisition system)


Organize & move that data…

The goal: Timely reporting of high quality, highly time-resolved ambient monitoring data.

• Data acquisition system is key– Digital or analog (we like digital! )– Disseminate locally and/or nationally

• Move it where?– AQS– Local users (AQ forecasters, etc.)– AIRNow-Tech


AIRNow

• Public medium• Focused on the

Air Quality Index (AQI)

• Current pollutant data (maps & data)

• Forecast products


AIRNow-Tech

• NOT public• Controlled

access; users only

• Data access– Reporting status– Tables– “Navigator” GUI


AIRNow-Tech Evolution

• Launched mid-2003– Allowed access to all the hourly pollutant data– Two subsequent upgrade versions (2005 & 2006)

• 2005 and 2006 improvements– New OBS data file formatting– Temporary site accommodations– Improved data display graphics– Interactive GIS based “Navigator” interface– Increased acceptable data parameters


Increased Reportable ParametersPollutant/Meteorological Parameter Naming Units

Ozone OZONE ppb PM2.5 mass PM2.5 g/m3PM10 mass PM10 g/m3

NO (nitric oxide) NO ppb NO2 (nitrogen dioxide) True measure NO2T ppb NOx-NO NO2 ppb NOy-NO NO2Y ppb NOx (nitrogen oxides) NOX ppb NOy (total reactive nitrogen) NOY ppb SO2 (sulphur dioxide) Conventional SO2 ppb SO2 Trace Level SO2T ppb CO (carbon monoxide) Conventional CO ppbCO Trace level COT ppb EC (elemental carbon) – PM2.5 EC g/m3 OC (organic carbon—not adjusted for O, H) – OC g/m3 BC (black carbon) BC g/m3 UVB (second channel of Aethalometer) UVB nanometeNO3 ion (nitrate-not adjusted for ammonium ion) NO3 g/m3 SO4 ion (sulfates-not adjusted for ammonium ion) SO4 g/m3 Ambient temperature TEMP ooC Wind speed WS m/s Wind direction WD degrees Relative humidity RHUM % Barometric pressure BARPR mb Solar radiation SRAD Watts/m2

Current Parameters

Precursor GasParameters

SpeciationParameters

MeteorologicalParameters

Required namingconvention

Precipitation Precip Millimeters


AIRNow-Tech Navigator


HYSPLIT Trajectories in Navigator


Overview of the Red Book

• There was a strong need to update the older QA Handbook Volume IV– Newer technologies – Digital Data Acquisition– New 40 CFR 58 Requirements (i.e., NCore)

• 1st Draft revision comments are due back to OAQPS on 2/28/07 for review and incorporation

• First pass revision and review included S/L/T operators, NOAA staff, and private/contract industry staff

• 2nd Draft will be more openly available for review– Air Mon Listserv shall be used to distribute


What’s New: Towers

Types of Towers AvailableInstallations of Towers

Tower Support


What’s New: Wind Systems

Section 2 discusses Propeller and Vane Systems

Section 2 discusses Cup and Vane Systems

Calibrations, torque test and distance constants


What New: Wind Systems

Relative sun azimuth angleSuncorrected(example shown is ~295°)

There is a great discussion on Magnetic Declination for wind direction traceability

Detailed discussion on Solar Noon method for wind direction traceability


What’s New: Wind Systems

y = 0.9857x + 0.0734

0

1

2

3

4

5

0 1 2 3 4 5

Wind Monitor AQ (ms-1)

So

nic

An

emo

met

er (

ms

-1)

Section 2 has in-depth discussion of sonic anemometers

The Handbook illustrates some side by side comparisons of prop vs. sonic


What’s New: Data Validation

In-depth discussion of data validation

Section discusses validation and verification

Discusses how to “link” met data to pollution data

Each “type of review” has a section number


Other topics included in the Handbook:

– Multiple tables of MQOsIllustrate differences between applications (PSD, PAMS, NCore, and others)

– Data acquisition and validation– Upper Air Systems

•OAQPS is also creating how-to video as an accompaniment to the new version


Summary

• EPA would like to see more of the existing data shared within our air monitoring communities (via AIRNow-Tech, AQS, local users)

• New monitoring requirements are the driver behind our renewed interest in met data

• Our goal is to provide appropriate, and updated guidance to S/L/Ts

EPA Precursor Gas Training Workshop Nealson Watkins & Dennis Mikel EPA - Office of Air Quality,...

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