Ambient Air Quality Monitoring Methods Lydia Scheer ITEP

2 What will we learn?  Reasons for monitoring ambient air quality  Methods available for different pollutants and/or parameters  Considerations for air monitoring  National and regional issues related to air monitoring

3 Why Monitor Air Quality?  Examine and characterize airshed  Health or environmental effects  Cultural reasons  Political issues  Economic or land-use planning  Gauge compliance with standards/regulations  NAAQS attainment or non-attainment  EPA Green Book lists NA areas (  Non-attainment: progress toward attainment  What control/prevention strategies are needed? Are they working?  Why is your tribe monitoring?  Answering this question will help to determine your air monitoring objectives

4 Evaluating Impacts  Think about monitoring objectives—why are you monitoring?  Consider impacts at both the receptor and the source  What is the level at source?  What are downwind/upwind levels?  What areas are most impacted and/or what areas are you concerned about? (receptors)  Establish baseline data representative of your area  Determine maximum, average pollutant concentrations  Will you be issuing health alerts or monitoring trends?  Are you meeting your objectives?

5 Network Considerations  “Network” can be a single site or multiple sites  Monitoring objectives  Meteorology & pollutant/precursor transport  Monitoring schedule  Site requirements, access and security, long-term viability  NAAQS monitoring: 40 CFR Part 58 Appendix E  Met monitoring: EPA-454/R  Special projects often have their own specific requirements  Necessary to review and modify network based on objectives and changes to surrounding conditions

6 Equipment Considerations  Monitors/samplers & sensors  FRM or FEM or not?  Must be FRM/FEM in order to compare to NAAQS (40CFR Part 53)  Collocation requirements for some types of monitoring  Ancillary equipment  Dataloggers  QA/QC equipment incl. flow meters, transfer standards, calibrators, etc.  Consumables  Grease/oil  Filters/filter tape  Concrete pad and shelter  Electricity requirements  A/C or heating needs

Regulatory Considerations  To officially compare to the NAAQS (for attainment designations or compliance) you MUST follow all requirements outlined in 40CFR Part 58  All EPA-funded projects involving data collection require approved QAPP 7

8 Pollutants & Parameters  Criteria pollutants  Particulates  PM10 (particulate matter < 10 mm)  PM2.5 (particulate matter < 2.5 mm)  Ozone  Lead  SO2  NOx  CO  Air Toxics (HAPs) and/or VOCs  Meteorological parameters  Acid & Mercury deposition

Particle Sizes Human Hair (~70 µm diameter) PM 2.5 (2.5 µm) PM 10 ( 10µm ) Cross Section: (~70 µm)

10 PM Filter-Based Samplers  HiVol (TSP or PM10 only), MiniVol, Partisol, others  Most HiVols & Partisols are FRM or FEM (epa.gov/ttn)  24-hour sample collected onto filter  Single channel or sequential option for Partisol  Filter mass weighed by lab to determine average ambient concentration  Samples can be analyzed further for constituents (speciation)

11 Filter-Based Pros & Cons  Filter-based equipment demands more resources  Personnel/time  Filters & other consumables  Laboratory analysis is costly  Less expensive to purchase than continuous samplers  Data are not “real-time”  MiniVols are more portable than larger equipment  MiniVol is not FRM or FEM  MiniVol can sample PM10 or PM2.5  MiniVol data is not legally-defensible

12 R&P PM2.5 Partisol FRM

13 HiVol & MiniVol

14 Credit:

15 Filters  47mm Teflon-coated Glass (PM2.5 or PM10)  47mm Quartz Fiber or pure Teflon (used for speciation)  8” x 10” Glass Fiber (PM10 HiVol)  Also specialized filters for some models  See examples

16 Continuous PM Monitors  Examples: TEOM, BAM, Nephelometer (some applications)  Collect samples “continuously” (readouts vary from every 5 minutes to every 1 hour)  Particles collected on filter tape or pad and weight (mass) is analyzed internally  Can be used for PM 10 or PM 2.5  Several models are FEM

17 TEOM & BAM

18 Continuous Pros & Cons  Provides data in “real-time”  Continuous equipment is more costly/fragile  Automated readings and no filters means minimized personnel time & lab costs  Some consumables and maintenance  Needs constantly reliable power source & adequate shelter  Requires Datalogger/DAS

19 Dataloggers/DAS  Electric or electronic computing devices that record measurements from other instruments  Various programming requirements and configurations  Datalogger input connection must match sensor output connection  Helpful to understand basic electricity concepts for troubleshooting

Datalogger Characteristics  Analog  Transmits voltage reading, translated into pollutant concentration or other parameter  Typically linear relationship between outputs and readings enables logging values anywhere within the range  “Noise” in analog connections can introduce error  Digital  Transmits specific values for pollutant concentration or other parameters  Values can increase or decrease only at specific, discrete intervals and not between intervals 20

21 Gaseous Monitoring Methods  “Passive” sampling  Often a chemical reaction involved, end sample is analyzed  Spectrophotometry and UV Photometry  Measures amount of light a sample absorbs  Primarily used for SO2 & Ozone  Chemiluminescence  Chemical reactions gives off light of a certain color  Used for O3, NOx, SOx and H2S

22 Sampling Equipment- Gaseous Pollutants

23 Air Toxics/HAPs  187 Hazardous Air Pollutants (HAPs)  Volatile & semi-volatile organic vapors  e.g., benzene, dioxin, formaldehyde, etc.  Heavy-metal dust, aerosols & vapors  e.g., mercury, nickel, antimony, etc.  Inorganic & mineral dust, aerosols & vapors  e.g., arsenic, asbestos, etc.  Radionuclides  Including radon

Sampling Methods - HAPs  Multiple methods depending on pollutant and emission process  Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air (Method TO-1, etc.)  Compendium of Methods for the Determination of Inorganic Compounds in Ambient Air (Method IO-1, etc.) 24 Photo courtesy of Frank BlackCloud, Spirit Lake Tribe

25 Meteorological Monitoring  Can be conducted along with ambient air monitoring  Helps to identify where pollution is coming from and/or where its impacts are greatest  Some ambient air samplers & dataloggers can record limited met data  Meteorological parameters to consider  Wind speed (how far?)  Wind direction (where/what direction?)  Temperature (affects aerosolization of particles)  Barometric pressure (impacts atmospheric conditions affecting transport)  Relative humidity (affects aerosolization of particles)  Solar radiation (affects formation of ozone)

26 TOWERS WIND SENSORS

27 Atmospheric Deposition  Wet Deposition (“Acid Rain”)  Monitored by National Atmospheric Deposition Program (NADP)  Acid deposition occurs when pollutants (primarily SOx or NOx) react in atmosphere with water vapor & returns to earth as precipitation (rain, snow, fog)  Measurements are made for pH and conductivity and precipitation  Dry Deposition  Monitored by the Clean Air Status & Trends Network (CASTNET)  Occurs when pollutants react, but not with water  Pollutants settle out of atmosphere as particles or gases

28 Mercury Deposition  Mercury Deposition Network part of NADP analyzes mercury samples from wet deposition monitoring  Monitoring for elemental and inorganic mercury conducted at the source  Organic mercury (methylmercury) samples can also be collected from environmental receptors  Aquatic and other wildlife  Wetlands/waterways  Sediments

29 Typical NADP Site

30 What We Just Covered  Ambient air pollution can be monitored, sampled and/or analyzed in numerous ways  Sampling types include filter-based, continuous, passive and chemical-based methods  All monitoring methods have pros and cons  Monitoring may or may not be important to meet certain needs of an air program  EPA regularly revises NAAQS standards