Montrose Air Quality Services is the nation’s largest provider of emissions testing services. With a dedicatedshutterstock_409803103
commitment to personalized collaboration and multiple office locations throughout the U.S., our technical expertise affords us the opportunity to conduct highly successful programs throughout the regulatory, energy, research and industrial communities.

MAQS offers an innovative group of professionals in several air quality disciplines. We continue to provide reliable and timely environmental data, gathered using the highest technical and ethical standards and with the least interruption to our clients’ daily operations.


Montrose’s Environmental Laboratory Services division, Enthalpy Analytical, is comprised of four laboratories servicing air, water, soil, and tobacco, testing under the brands Enthalpy Analytical and Curtis & Tompkins. Founded in the late 1800’s and early 1900’s, these labs have helped pioneer methods and tests still being used today.

Environmental Laboratory

Among others, our laboratories hold accreditations from: National Environmental Laboratory Accreditation (NELAC); Environmental Laboratory Accreditation Program for California (CAELAP), Nevada (NVELAP), Oregon (ORELAP), and Virginia (VELAP); Louisiana Department of Environmental Quality (LDEP); New Jersey Department of Environmental Protection (NJDEP); Texas Commission of Environmental Quality (TCEQ); and Pennsylvania Department of Environmental Protection (PADEP).


Engineering and Regulatory Compliance Services division a full range of environmental assessment, air quality management, engineering and construction services under the brand ES Engineering Services. The certified professionals plan, design, and build innovative and scientific solutions for the private and public sector. ES Engineering Services offers expertise in Renewable Energy, Site Assessment & Remediation, Solid Waste & Recycling, and Water & Wastewater Treatment.

work guy

ES Engineering Services also provides on-site operations management services for wastewater treatment facilities and a variety of waste to energy facilities. ES Engineering Services offers multidisciplinary staff providing integrated, innovative, and individualized solutions to clients’ environmental compliance issues with offices located across the country.


Air Analysis

  • Alkanes
  • Extractive FTIR spectroscopy
  • Field GC
Fixed Gases
Gasoline (C1-C6)
Hydrogen Sulfide
  • NCASI Methods
  • Organics by EPA Method 18 – hundreds of analytes available
  • Ozone Precursors
  • Passive fence line concentrations
  • Radiello device analysis
  • SUMMA canister analysis – ppt to % levels
  • TPH-Diesel
  • Volatiles

Air Toxic Contaminants & HAPs Testing

  • California AB 2588
  • Clean Air Act, Title III MACT
  • ICR Test Programs
  • Toxics Assessment Inventory
  • Test Method Evaluation
  • HAPs Characterization
  • BIF Testing
  • Boiler MACT
  • EPA ERT Reporting

CEMS Certification and Auditing

  • RATA, RAA, CGA, FAT, Linearity
  • 40 CFR, Parts 60 and 75 Testing
  • Predictive Emissions Monitoring (PEMS)
  • Alternative Monitoring Systems (AMS)
  • RICE MACT Testing
  • Quality Assurance Plans
  • CEMS Problem Diagnosis
  • Temporary CEMS

Combustion Engineering and Emissions Profiling

  • Emissions Profiling
  • Fuel Analyses
  • Process Optimization
  • Fuel to Air Ratios
  • NMOC Speciation
  • 3-D Flow Profiling
  • Engineering Studies
  • Performance Guarantee Testing

Control and Destruction Efficiency Specialists

Diagnostic Performance Testing

Fish-bioassay Analysis

Food Analysis

  • Ash
  • Fat, Crude
  • Protein
  • Moisture

FTIR Spectroscopy Services

Leak Detection and Repair

  • Method 21 Fugitive Emissions Inspections
  • Tagging and Inventory
  • Online Database Management
  • Optical Gas Imaging Inspections (FLIR Camera)
  • Tank Seal Inspections
  • DOT Pipeline Surveys
  • Greenhouse Gas Inspections
  • Tank Maintenance
  • Emissions Calculations
  • Inspection and Monitoring Plans
  • Third Party Audits
  • Applicability and Exemption Review and Documentation
  • Vapor Recovery System Trouble Shooting
  • Regulatory Review

Metals Analysis

  • CAM Metals
  • ICP Metals full scan
  • ICP Metals single element
  • ICP-MS Metals full scan
  • ICP-MS Metals single element
  • Mercury
  • RCRA Metals
  • STLC/TCLP/SPLP Extraction

Meteorological and Ambient Air Monitoring

  • Siting Analysis and Instrument Specifications
  • Net Working and Remote Communications
  • Quality Assurance and Quality Control
  • Field Performance and System Audits
  • Complete Maintenance, Operations and Documentation
  • Data Acquisition, Validations and Reporting
  • Data Hosting – Web Based
  • Meteorological, Particulate and Air Chemistry Parameters
  • Instrumentation and Control

Microbiology Analysis

  • Coliform, Total
  • Coliform, Fecal
  • Coliform (Presence/Absence)
  • E. Coli
  • Standard Plate Count – Aerobic
  • Standard Plate Count – Anaerobic
  • Legionella
  • Listeria
  • Salmonella
  • Iron Bacteria
  • Sulfur Bacteria
  • Yeast & Mold
  • Enterococcus
  • Lactobacillus
  • Inhibitory Residue
  • Water Suitability
  • Pseudomonas
  • Staphylococcus
  • Microscopic Examination
  • Bacteria Identification

Organic Analysis

  • 1,4-Dioxane
  • Ethanol/Methanol
  • Herbicides
  • Organochlorine & PCBs
  • Organochlorine Pesticides
  • Organochlorine Pesticides & PCBs
  • Organophosphates
  • Polynuclear Aromatic Hydrocarbons
  • Semi Volatiles
  • Total Trihalomethanes
  • TPH-Carbon Chain (C6-C44)
  • TPH-Diesel
  • TPH-Diesel & Motor Oil
  • TPH-Gasoline
  • Volatiles

Regulatory Compliance Testing

  • Thousands of Tests Performed
  • Ultra-Low Emissions Measurement
On-Site Gaseous Emissions Results
  • On-Site Wet-Chemistry Results
  • Emission Factor Verification
  • Port Placement Procedures
  • Hazardous Waste Trial Burns

Particular Matter Experts

  • PM10 and PM2.5
  • Particle Size Distribution
  • Visible Emissions
  • Detached Plume Problems
  • Condensable Headaches
  • Ambient Monitoring
  • Ultra-Low Concentrations

Power Plant Commissioning Test Programs

SCR and SNCR Optimization Expertise

  • Ammonia Injection Balancing
  • CO Catalyst Efficiency
  • Temperature Profiling
  • Flow Rate Profiling
  • Multiple Locations Simultaneously

Soil, Water, Hazardous Waste Analysis

  • Agricultural Suitability (pH, Boron, Calcium, Magnesium, Chloride, Salinity, Exchangeable Sodium Percentage)
  • Fertility Analysis (pH, Boron, Nitrate-Nitrogen, Phosphate, Phosphorus PO4-P, Potassium, Salinity)

Wet Chemistry Analysis

  • Acidity
  • Alkalinity
  • Ammonia
  • Anions (fluoride, chloride, nitrate, nitrite, bromide, o-phosphate, sulfate)
  • Biochemical Oxygen Demand
  • Bromate
  • Chemical Oxygen Demand
  • Chlorate
  • Chloride
  • Chorine, Total & Free
  • Chorophyll
  • Color
  • Corrosivity
  • Cyanide, Amenable
  • Cyanide, Total
  • Fluoride
  • Formaldehyde
  • Free Carbon Dioxide
  • Hardness
  • Hexavalent Chromium
  • Ignitability (closed cup)
  • Inorganic Nitrogen
  • Iodide
  • MBAS
  • Mercaptans
  • Moisture
  • Nitrate
  • Nitrate + Nitrite-N
  • Nitrite
  • Odor
  • Oil & Grease
  • Organic Nitrogen
  • Ortho-Phosphate
  • Paint Filter Test
  • Perchlorate
  • pH
  • Phenols, Total
  • Phosphate, Total
  • Phosphorus, Total
  • Reactive Cyanide
  • Reactive Silica
  • Reactive Sulfide
  • Redox Potential
  • Settleable Solids
  • Sodium Absorption Ratio (SAR)
  • Specific Conductance
  • Sulfate
  • Sulfide, Total
  • Total Dissolved Solids
  • Total Kjeldahl Nitrogen
  • Total Nitrogen
  • Total Organic Carbon
  • Total Solids
  • Total Suspended Solids
  • TRPH
  • Turbidity
  • Volatile and Non-Volatile solids