Air Quality is a growing concern in India; more and more people are getting aware of this issue. To be honest, we didn’t even bother about what the air quality meant until today, when we hear about its after effects directly affecting our lives. And why should we? We’re breathing air day in and day out.
Be it smaller towns or bustling metros, Air Quality is affecting each one of us. For us, keeping a tab on the Air Quality Index isn’t just about watching the geographical map or staring at those varying digital numbers – it’s about protecting our health, and those numbers mean something.
In this post, you’ll learn what AQI numbers mean and how to read them and make sense from them. And how you can monitor indoor/outdoor AQI with smart devices.
What is AQI?
AQI stands for Air Quality Index. It denotes the amount of pollutants in the air. It reflects how polluted the air is or is about to become by measuring multiple pollutants from the air. Thankfully, the Central Government of India has introduced the National Air Quality Index, a simple, easy-to-understand measurement metric that simplifies complex Air Quality data into a single number, nomenclature, and color.
How is AQI Calculated in India?
AQI Index consists of six AQI categories, each denoted with a color band further associated with an AQI number, namely:
- Good (Dark Green Color)
- Satisfactory (Green)
- Moderately Polluted (Yellow)
- Poor (Orange)
- Very Poor (Red)
- Severe (Dark Red)
The motto is “one number – one colour – one description” to help people understand air quality. Each category was decided based on ambient concentration values of air pollutants and their health impacts, also known as health breakpoints. The pollutants that are considered are PM2.5, PM10 (particulate matter), NO₂, SO₂, CO, O₃ (ozone), NH₃ (ammonia), and Pb (lead), for short-term up to 24 Hours.
The sub-index for a pollutant is calculated from its measured concentration using a linear relationship.
For example, for PM2.5:
- Concentration of 31 µg/m³ → sub-index 51
- Concentration of 45 µg/m³ → sub-index 75
- Concentration of 60 µg/m³ → sub-index 100
The highest (worst) sub-index among all pollutants determines the overall Air Quality Index (AQI).
| AQI Value Range | Category | What it means |
|---|---|---|
| 0-50 | Good | Air quality is satisfactory. Minimal risk. |
| 51-100 | Satisfactory | People with lung/heart conditions may feel discomfort; healthy persons generally feel fine. |
| 101-200 | Moderate | Most people may experience some respiratory discomfort; sensitive groups are at higher risk. |
| 201-300 | Poor | Most people may experience some respiratory discomfort; sensitive groups at higher risk. |
| 301-400 | Very Poor (or Severe) | Increased health impact; even healthy persons may experience effects. |
| 401-500 | Hazardous | Serious health risk for all; avoid outdoor activity. |
So the idea is, the higher the AQI, the worse the air is to breathe, and a potential health risk. A low AQI value means better air quality.
Interpreting the Numbers – What to do
Once you know the AQI reading around you, the next step is how to respond to it.
- 0-50 (Good): Safe to go outdoors and continue with normal activities.
- 51-100 (Satisfactory): Generally safe; however, if you are very sensitive (with any asthma, chronic lung/heart issues), you’d be a little cautious.
- 101-200 (Moderate): If you have lung/heart disease, older age, or children, you must consider reducing strenuous outdoor activity.
- 201-300 (Poor): Most people may feel discomfort outdoors. And, Sensitive groups must avoid prolonged outdoor exertion.
- 301-400 (Very Poor/Severe): Getting outdoors is risky for everyone. Healthy people should limit outdoor time, and sensitive groups must stay compulsively indoors as much as possible.
- 401-500 (Hazardous): All should avoid any outdoor physical activity; stay indoors, close windows, and use masks/indoor air filters.
Note: With AQI reading, you won’t get to know the exact composition of pollutants in the air is but it gives you a quick health-risk summary.
Why monitor air quality yourself (especially indoors)
AQI in India is monitored by a network of continuous ambient air quality monitoring stations (CAAQMS) for real-time data and manual monitoring stations for periodic analysis. These stations are operated by Government institutions like the Central Pollution Control Board (CPCB), State Pollution Control Boards, and organizations like the Indian Institute of Tropical Meteorology (IITM).
Continuous stations provide real-time AQI for public information, while manual stations measure pollutant concentrations for chemical analysis and share the data periodically.
So, as you might have guessed, AQI readings vary by location. AQI data provided by the monitoring stations might not be exactly accurate for your locality, as those stations are deployed far away from your place and provide data that might be true for that particular zone. If a monitoring station is near a construction site or a road, the reading would obviously be higher than that from a monitoring station near a calm housing society.
It makes sense to measure AQI in your locality and especially in your home. And if you care enough for your family’s health, then you must definitely keep a tab on the air quality around you. Just as we measure the air quality outdoors, we must also look out for indoor air pollutants at our homes, offices, or classrooms from cooking, outdoor infiltration, dust, and VOCs.
Also, AQI gadgets and portable AQI monitors now make it easy to check PM2.5, CO2, VOCs, etc, in real time and take action (ventilation, purifier, mask) accordingly.
Recommended Budget-Friendly AQI Gadgets
Here are some useful devices that you can place in your home or workspace, that’ll help you keep a check on the quality of air you’re breathing throughout the day.
INKBIRDPLUS 6-in-1 Indoor Air Quality Monitor – This compact Air Quality Meter is a must-have if you constantly change places or are on the go. It measures CO2, PM2.5, PM10, AQI, Temperature, and Humidity. Most importantly, you can set an AQI alarm if the AQI crosses 100.
Temtop Air Quality Monitor – This air quality meter is packed with PM2.5, AQI, Temperature, and Humidity measurements. It can last up to 60days on a single charge. It comes with a magnetic stand to keep it on the table or stick it on the fridge/cuboards.
SMILEDRIVE Portable Air Quality Pollution Monitor Meter – This indoor smart meter comes with a colorful LED screen, making the readings visible in the night too. The meter can measure PM 2.5/1/10, TVOC, HCHO, Temperature, and Humidity. This is a very popular meter and is often sought after.
How to pick a good Air Quality Monitor:
While looking for an AQI monitor for you, make sure you look out for the following features:
- The monitor measures PM2.5 (the most critical fine particulate) and preferably PM10.
- Check if it shows a “traffic-light” colour (Red, Orange, Green) or a simplified AQI reading.
- Alerts you with an alarm/buzzer when AQI levels reach high levels >100
- If you need CO2 or VOC (Volatile Organic Compounds) for indoor air quality/ enclosed rooms, pick a monitor that includes those.
- Sensor Accuracy: Not all AQI monitors are indeed 100% correct, and they may have some error rate. Check if they’re calibrated well. If possible, you must look for laser-scattering sensors for PM
- If you tend to roam a lot, make sure the AQI monitor is portable, rechargeable, and has a backlight for low-light visibility.
- Check if the unit has WiFi/Bluetooth to monitor readings remotely.
- Placement matters; if you tend to place an outdoor AQI monitor indoors, near a window, dusty corridor, or cooking area, then it may lead to misleading readings. Keeping the monitor.
- After-sales support is crucial too. Check the availability of service, sensor replacement (yes, sensors wear out and need to be replaced), firmware updates, etc.
- You can find AQI monitors that cater to all budgets. You often trade off features, build, connectivity, and sensor quality. While buying, prefer the quality of the product over its price.
And not to mention, for indoor Air Quality monitoring, solely AQI meters won’t do much, you must combine with an air purifier or ventilation improvements if you find the readings are nearing high.
Practical Tips to Survive Bad AQI
- Those living in Metro Cities like Mumbai, Delhi, Kolkata, etc., are advised to regularly check their real-time AQI from official platforms like CPCB, MPCB (for Maharashtra), etc. Here are some popular links that you can check out:
- https://airquality.cpcb.gov.in/AQI_India/ – National AQI Monitoring
- https://mpcb.gov.in/air-quality – Maharashtra AQI Monitoring
- https://www.aqi.in/in – Private AQI Monitoring website
- In winter months, along with the chill and fog, the wind can bring along thick smog consisting of various harmful pollutants. The AQI can suddenly spike, especially in states where stubble burning happens, including Punjab/Haryana, and the AQI can spike alarmingly high.
- Even if the outdoor AQI is moderate, and you’re working inside a closed room for long hours, your monitor might show high levels of PM/CO2, which is because of poor ventilation or cooking smoke. Open windows while cooking and reduce indoor smoke, like incense or smoking.
- Children and elderly people with asthma or heart disease must be extra careful when the AQI is between 100-200. They must compulsively use N95/FFP2 masks when getting outdoors.
- Use public transport, avoid unnecessary burning waste/keep windows closed and the air purifier running.
In Summary: Make Checking AQI a Habit
AQI is more than just a number – it’s about understanding what the number means for our health, and its effect on our lives and behavior. Getting to breathe cleaner air is not just a luxury; it is a necessity to lead a healthier life.
It’s not too late yet. To keep yourself safe, make it a habit to read AQI readings regularly and pair yourself with a good indoor AQI monitor to gain control over your environment, and this will help you to make wise decisions whether to go out for a jog or switch on your indoor air purifier.