Indoor Air Quality Testing Standards
Indoor Air Quality Standards are the permissible limit for different indoor air pollutants & factors that affect indoor air quality. As per Environmental bodies like EPA or CPCB, it should be Below limits to keep environmental balance.
A home is a place where we feel safe, don’t we? But, are we truly safe? Are we truly safe from all the bacteria, viruses and indoor air pollutants lingering in our home?
It is stated by scientists that indoor air can be more polluted than the air outside.
You must be wondering how?
When it comes to indoor air, due to improper ventilation the pollutants get trapped indoors and there is a low exchange of indoor air with fresh air, thus making us prone to getting affected by indoor air pollutants.
How to ensure we have good Indoor Air Quality?
To keep our home healthy and safe, we can always do an indoor air quality assessment. For this, we can always hire professionals (That’s Us !) to analyse our indoor air quality or buy indoor air quality test kits to analyse our indoor air quality by our self.
But any assessment/analysis is not complete until you conclude. To conclude about the quality of our indoor air we must first compare the results with some standards/guidelines and then rate the quality of indoor air based on that standards/guidelines.
How would we rate our Indoor Air Quality?
To be able to easily rate the quality of indoor air, certain guidelines/standards have been designed. These standards are different for each country. The reason for them to be different is every place has different climatic conditions and different pollutant range.
IAQ Testing Standards Used in India
In India, no separate IAQ standards/guidelines are yet designed. But, some components involved in determining indoor air quality are considered in the National Building Code 2016 (NBC). The other standards we may look up to are given by World Health Organisation (WHO), Occupational Safety and Health Administration (OSHA) and the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE).
Learn more about Indoor Air Quality and Health
Why are IAQS guidelines designed?
Back in school after our exams, we used to get grades, right? These grades; A, B, C, D were set on some guidelines; like if a student scores above 80 he gets an A grade and so on.
Thus, these guidelines give us a framework and help us in a way to achieve the best.
In scientific analysis, the standards/guidelines are based on looking towards the safety of the people. These are set according to the pollutant and its ability to affect us. Thus the standards/guidelines are set at the lowest level and this level is known as the permissible level. To achieve good indoor air quality, the pollutant levels in your indoor air should all be way below the permissible levels.
What are the 4 major indoor air pollutants?
The four major indoor air pollutants are:
- Particulate Matter (PM2.5 and PM10):
Tiny airborne particles like dust, smoke, and soot can penetrate deep into the lungs and cause respiratory problems, heart diseases, and other health issues. PM2.5 (smaller than 2.5 microns) is particularly harmful due to its ability to enter the bloodstream. - Volatile Organic Compounds (VOCs):
These are chemicals emitted from household products like paints, cleaning agents, and furniture. Common VOCs include formaldehyde and benzene, which can cause eye irritation, headaches, and long-term health effects like cancer. - Carbon Dioxide (CO₂):
While naturally present indoors, excessive CO₂ levels from poor ventilation or overcrowding can cause discomfort, reduced cognitive function, and fatigue. High CO₂ levels indicate inadequate air circulation. - Carbon Monoxide (CO):
Produced by incomplete combustion from heaters, stoves, or fireplaces, CO is a colorless and odorless gas. Even low levels can cause dizziness and nausea, while prolonged exposure may be fatal due to oxygen deprivation.
These pollutants significantly affect indoor air quality and require proper monitoring and control to ensure a healthy living environment.
Indoor Air Quality Testing Standards:
The table below gives a gist of IAQ testing standards and the permissible limit for different indoor air pollutants and factors that affect indoor air quality.
Indoor Air Quality Standards
Indoor Air Quality Standards in India
These standards define safe limits for common indoor pollutants such as PM2.5, PM10, and CO₂, ensuring public health and compliance with environmental regulations.
| Pollutant | Standard Limit | Health Effects |
|---|---|---|
| PM2.5 | 40 µg/m³ (annual), 60 µg/m³ (24-hour) | Respiratory and cardiovascular issues |
| PM10 | 60 µg/m³ (annual), 100 µg/m³ (24-hour) | Lung irritation and reduced lung function |
| Carbon Dioxide (CO₂) | 1000 ppm | Fatigue, reduced cognitive performance |
| Carbon Monoxide (CO) | 2 mg/m³ (8-hour) | Dizziness, headaches, nausea |
| Volatile Organic Compounds (VOCs) | Indoor levels should be as low as possible | Eye irritation, headaches, long-term cancer risk |
Indoor Air Quality Standards 2021
The 2021 WHO standards introduced stricter limits for PM2.5 and PM10, focusing on minimizing health risks associated with particulate matter exposure.
| Pollutant | WHO 2021 Limits | India’s Limits |
|---|---|---|
| PM2.5 | 5 µg/m³ (annual), 15 µg/m³ (24-hour) | 40 µg/m³ (annual), 60 µg/m³ (24-hour) |
| PM10 | 15 µg/m³ (annual), 45 µg/m³ (24-hour) | 60 µg/m³ (annual), 100 µg/m³ (24-hour) |
| Carbon Monoxide (CO) | 4 mg/m³ (24-hour) | 2 mg/m³ (8-hour) |
Indoor Air Quality Standards 2022
WHO 2022 guidelines further emphasized limiting exposure to pollutants like ozone (O₃) and nitrogen dioxide (NO₂) for long-term health benefits.
| Pollutant | Updated WHO 2022 Limits |
|---|---|
| PM2.5 | 5 µg/m³ (annual), 15 µg/m³ (24-hour) |
| PM10 | 15 µg/m³ (annual), 45 µg/m³ (24-hour) |
| Ozone (O₃) | 100 µg/m³ (8-hour average) |
| Nitrogen Dioxide (NO₂) | 10 µg/m³ (annual), 25 µg/m³ (24-hour) |
Indoor Air Quality Standards Comparison
This table compares standards from NBC, ASHRAE, WHO, and OSHA for key pollutants such as CO, CO₂, PM, and more.
| Indoor Air Quality Parameters | Indoor Air Quality Standards | |||
|---|---|---|---|---|
| NBC 2016 | ASHRAE | WHO | OSHA | |
| CO | 20 mg/m³ | 9 ppm (8 hours) | 10 mg/m³ | 50 ppm (8 hours) |
| CO₂ | – | 1000 ppm | – | 5000 ppm |
| PM | 60 µg/m³ | – | – | – |
| PM10 | – | – | 50 µg/m³ | 15 mg/m³ |
| PM2.5 | – | – | 25 µg/m³ | 5 mg/m³ |
| SO₂ | 80 µg/m³ | – | 20 µg/m³ | 5 ppm (8 hours) |
| NO₂ | – | – | 40 µg/m³ (Annual) | 5 ppm (8 hours) |
| Temperature | 26 ± 2 °C | 22.8 to 26.1 °C | – | – |
| Humidity | 40% to 70% | 30% to 65% | – | – |
How To Rate Indoor Air Quality?
Once an indoor air quality assessment has been carried out and the parameters are measured, the results can be compared with the standards available. Once you compare the results you will get an idea about the level of indoor air pollution and accordingly your indoor air quality would be rated.
For Ex; If the levels of Carbon Monoxide (CO) is under the permissible limits prescribed in the standards, but the levels of Total volatile organic compounds (TVOCs) is way above the permissible limit, then the quality of your indoor air would be rated as poor and recommendations would be provided to enhance the quality of your indoor air.
Indoor air pollution has become a huge concern nowadays. Some diseases and disorders people are suffering from are a result of indoor air pollution. We spend most of the time indoors and thus to maintain good health and quality of life, it becomes necessary to continuously monitor indoor air quality and to sustain its quality.
Read More How to Measure Indoor Air Quality?
Indoor Air Quality Monitoring for Office Buildings
We Perfect Pollucon Services offer services in Indoor air quality Monitoring / Testing. Feel free to contact us in case of any queries.
Environmental Protection Agency of US first designed primary National Ambient Air Quality Standards in year 1990 for six pollutants. Other Agencies like CDC, ASHRAE and OSHA also came up with their Indoor Air Quality standards for maintaining clean air in buildings.
The normal range for indoor air quality varies depending on the pollutant being measured. For example, particulate matter (PM2.5) should ideally be below 12 µg/m³, and carbon dioxide (CO₂) levels are typically safe below 1,000 ppm. Other pollutants, like carbon monoxide (CO), should remain under 9 ppm, while volatile organic compounds (VOCs) and formaldehyde should be as low as possible to maintain healthy indoor environments.
Good indoor air quality is characterized by low levels of pollutants such as particulate matter (PM2.5 below 12 µg/m³), carbon dioxide (CO₂ below 1,000 ppm), and minimal volatile organic compounds (VOCs). It ensures a healthy, comfortable, and safe environment for occupants, free from harmful contaminants.
ISO 16000 is the standard for indoor air quality, providing guidelines for measuring pollutants like VOCs, PM, formaldehyde, and CO₂. It ensures consistent testing and compliance for healthier indoor spaces.
For PM2.5, the standard is 12 µg/m³ (good air quality), and for PM10, it is 50 µg/m³ (24-hour average). These standards are based on health-focused guidelines.
Indoor air quality can range from good (low pollutant levels, healthy) to poor (high levels of PM, CO₂, and VOCs, causing discomfort or health risks). An IAQ index is often used for classification.
The IAQ index is calculated by measuring pollutant concentrations (e.g., PM2.5, CO₂, VOCs) and comparing them to standard thresholds. Each pollutant is scored, and the highest score determines the overall IAQ category.
Indoor air quality can be tested using portable monitors or laboratory-grade instruments to measure pollutants like PM2.5, CO₂, VOCs, and temperature. Professional services provide detailed assessments and recommendations.
Perfect air quality has PM2.5 levels below 12 µg/m³, CO₂ under 1,000 ppm, and negligible VOCs or harmful gases, ensuring a safe, clean, and comfortable environment.
Poor indoor air quality occurs when pollutants like PM2.5 exceed 35 µg/m³, CO₂ is above 1,500 ppm, or VOCs are high, leading to health issues like headaches, allergies, and respiratory problems.
The CO₂ limit for healthy indoor air is 1,000 ppm, with levels above this indicating poor ventilation. Concentrations above 1,500 ppm may cause discomfort and reduced cognitive performance.
Class 3 air is defined in cleanroom standards like ISO 14644, allowing a maximum of 35 particles per cubic meter for sizes 0.5 microns or larger. It ensures ultra-clean environments.
WHO standards recommend annual PM2.5 levels below 5 µg/m³ and PM10 below 15 µg/m³ to reduce health risks. For CO₂, proper ventilation is essential to maintain safe levels.
Good indoor air quality has PM2.5 below 12 µg/m³, CO₂ under 1,000 ppm, and low VOCs. It ensures comfort, health, and optimal productivity.
AQI is calculated using pollutant concentrations like PM2.5, PM10, NO₂, and O₃. Each pollutant’s value is scaled to an index (0-500), and the highest index determines the overall AQI.
PM2.5 standards are 12 µg/m³ (annual average) and 35 µg/m³ (24-hour average), while PM10 standards are 50 µg/m³ (annual average) and 100 µg/m³ (24-hour average). These ensure air quality is safe for health.