Most of the substances that pollute indoor air are impossible or very difficult to detect with human senses alone, and the goal of indoor air quality is to prevent exposure to them in the first place. The US Environmental Protection Agency has created a compendium of the methods that can reliably determine the presence of pollutants in indoor air.
However, before proceeding with sophisticated air quality tests, the US EPA recommends a performance verification of the HVAC installation in a building. If there are performance issues, poor air quality is almost certain, and the tests may represent a waste of time and money.
In this article you will find a comprehensive guide of the different steps that should be taken when analysing the indoor air quality of offices and buildings. Thus helping you when hiring the services of a contractor since after reading this post you will have a better understanding of what they should do and how they should do it.
Step 1: HVAC Verification
If the HVAC system is not installed and operated according to applicable standards, IAQ is negatively affected. Two of the most relevant standards for IAQ are the following, both published by ASHRAE:
- Standard 62.1-2016: Ventilation for Acceptable Indoor Air Quality
- Standard 62.2-2016: Ventilation for Acceptable Indoor Air Quality in Low-Rise Residential Buildings
The main goal of these standards is to ensure that ventilation rates and other related design parameters meet minimum requirements to guarantee indoor air quality, creating suitable conditions for human occupancy and minimizing adverse health effects. Both standards have the same goal, but 62.1 is intended for commercial locations, while 62.2 is for the needs of low-rise residential settings (single-family and multifamily).
ASHRAE has also published its own Indoor Air Quality Guide, which provides an overview of the best practices during the design, construction and commissioning process.
In a few words, HVAC systems must be able to capture and remove pollutants effectively, without being a source of pollution themselves. Mold and mildew are notorious for their ability to pollute components such as evaporators and air ducts.
Carbon dioxide concentration is a reliable indicator of ventilation performance.
Step 2: Air Quality Testing
The US EPA compendium of air quality testing methods is divided into 10 chapters, each dealing with a different category of pollutants or air quality issues. For each category of pollutants, the US EPA compendium provides one or more air sampling methods, for a total of 20:
Compounds or IAQ Issue
Volatile organic compounds (VOCs) with boiling point from 80 to 200°C
Stainless Steel Canister
Solid Adsorbent Tubes
Nicotine, in both gaseous and particulate form
XAD-4 Sorbent Tube
Treated Filter Cassette
Carbon monoxide (CO) andcarbon dioxide (CO2)
Nondispersive Infrared (NDIR)
Gas filter correlation (GFC)
Electrochemical oxidation – only for carbon monoxide
Air exchange rate
Perfluorocarbon Tracer (PTF) Tracer Gas
Continuous Luminox Monitor
Palmes Diffusion TubePassive Sampling Device
Formaldehyde (CH2O) and otheraldehydes/ketones
Solid Adsorbent Cartridge
Continuous Colorimetric AnalyzerPassive Sampling Device
Polynuclear aromatic hydrocarbons
Medium Volume PUF/XAD-2 Sampler
Low Volume PUF Sampler +GC/ECD Detection
Annular Denuder System
Size-Specific ImpactionContinuous Particulate Monitor
The US EPA recommends that these tests only be carried out after a verification of HVAC performance, and by a laboratory with at least 5 years of experience conducting them. At least one sampling point must be selected for every 25,000 square feet of floor area, and air samples should be collected for three consecutive days.
1) Volatile Organic Compounds (VOC) Testing
Indoor environments are exposed to many sources of VOCs: they may be drawn from outdoors, some manufacturing processes release them, and there are products that release VOCs spontaneously. VOCs can irritate the skin, eyes and respiratory system, and may lead to the development of severe illnesses with long-term exposure.
The two testing methods suggested by the US EPA to detect VOCs are the stainless steel canister method (IP-1A) and the solid adsorbent tube method (IP-1B). Both methods are based on capturing VOCs and analyzing them with gas chromatography. The main difference lies in how VOCs are captured in each case.
2) Nicotine Testing
The two testing methods suggested by the US EPA are the XAD-4 Sorbent Tube (IP-2A) and the Treated Filter Cassette (IP-2B). Just like with VOC sampling, these two methods are based on capturing nicotine to be analyzed with gas chromatography.
3) Carbon Monoxide and Carbon Dioxide Testing
Carbon monoxide is the result of incomplete combustion, and can be lethal to humans even in moderate concentrations. On the other hand, carbon dioxide is not dangerous unless it reaches very high concentrations, but is a reliable indicator of ventilation performance.
4) Air Exchange Rate Testing
Although this test does not detect a specific pollutant, it helps assess the air exchange rate between a building’s interior and exterior.
5) Nitrogen Oxide Testing
The US EPA proposes one active method and two passive methods to test the concentration of nitrogen oxides in indoor air. As buildings have become more airtight to improve energy efficiency, nitrogen oxide monitoring has gained increased importance. Nitrogen oxides irritate the airways and contribute to the formation of particulate matter, which is detrimental for respiratory and cardiovascular health.
6) Formaldehyde (CH2O) and other Aldehydes and Ketones
Formaldehyde and other similar compounds irritate the eyes, skin and respiratory system, and large enough concentrations can cause severe organ damage. Formaldehyde is released by many types of furniture and construction materials, and concentration can become particularly high in airtight buildings. Therefore, these substances are given high priority by the EPA, and three measurement methods are provided for indoor spaces.
7) Polynuclear Aromatic Hydrocarbons Testing
Polynuclear aromatic hydrocarbons (PAHs) have been linked with genetic mutations and cancer, and as a result the US EPA decided to include a specific testing method for them in its compendium.
If there are performance issues in the HVAC system, poor air quality is almost certain, and running Air Quality tests may represent a waste of time and money.
8) Pesticides Testing
Since pesticides are commonly used in urban settings, and the air tightness of modern buildings favors their accumulation, it is very important to verify that indoor air is free from harmful concentrations.
9) Reactive Gases Testing
Fossil fuel combustion and waste processing release various acidic and basic gases, which have adverse health effects by themselves and also contribute to the formation of particulate matter, which brings its own set of health issues. The US EPA developed Method IP-9 specifically to test indoor air for these substances.
10) Particulate Matter Testing
The concept of particulate matter (PM) is used to refer to a broad range of compounds that may be found in the air, composed of airborne solids and low-vapor-pressure liquid droplets. The size of PM ranges from 0.01 to 100 microns, but particles below 10 microns are of the greatest concern because they can be inhaled by the human respiratory system. The EPA compendium provides two methods for PM testing.
Air quality testing is a scientific discipline by itself, requiring sophisticated laboratory equipment and a detailed knowledge of testing procedures. However, Foobot provides a reliable monitoring solution for the needs of most buildings:
- By monitoring temperature and humidity, it provides a snapshot of HVAC effectiveness. If either of these variables falls outside the optimal range, corrective action can be taken, automatically.
- Foobot can detect particulate matter below 2.5 microns, the most harmful size range, as well as volatile organic compounds like benzene and formaldehyde.
Indoor air quality monitoring can help you prevent many health issues, from mild irritation and allergies to life-threatening conditions such as heart disease and nervous system damage.
Click here to learn more about what Foobot Smart Air System can do for your building or office.