What AQI is unhealthy?

Nowadays the Air Quality Index of most of the cities is higher than 100. What does this tell us about the air quality? It says that the air we breathe is not safe, we are also inhaling the pollutants along with the air. This has raised a lot of concern about the air quality. 

To tackle this issue the Environmental Protection Agency (EPA) Monitors the air quality of five major pollutants namely; SO2, NO2, Ozone, CO and particulate matter (both PM10 and PM2.5). Based on the concentration level of each pollutant a certain value is assigned between the range 0-500. The higher values are correlated to higher pollution levels and vice versa. 

So, in this article we will discuss what AQI is unhealthy. What air quality  should we stay indoors and what measures can we take to protect ourselves from the impact of harmful pollutants? So read this article till the end to know more. 

What AQI is unhealthy?

According to Accuweather the unhealthy air quality level means that the concentration level of criteria pollutants having the values greater than 100 are unsafe.

 As the values increase the air quality keeps deteriorating. So the values

  • 151-200 is considered as unhealthy
  • 201-300 is considered as very unhealthy 
  • 201-500 is considered as hazardous. 

 How do we estimate the air quality?

The Air Quality Index proves to be helpful to estimate the air quality Based on the concentration level of each criteria pollutant a certain value is assigned between the range 0-500. The higher values are correlated to higher pollution levels and vice versa.

Below is the table depicting the air quality parameters:

Air Quality IndexEPA advisory for major pollutants including Ozone, PM10 AND PM2.5Color scheme for these indices
0-50 Good Great day to be outdoors Green 
51-100 ModerateNice time to be outdoors Yellow 
101-150 Unhealthy For Sensitive Groups Healthy people should limit prolonged outdoor exertion
Sensitive groups should reduce outdoor exertion for a long time.
151-200 UnhealthyHealthy people should limit prolonged outdoor exertion 
Sensitive groups should avoid outdoor exertion for a long time
201-300 Very Unhealthy Everyone should limit their outdoor exertion. Purple 
301-500 HazardousOutdoor exertion should be avoided Maroon



What are the Health effects of these criteria pollutants?

These air pollutants have the following health effects:

Health impacts of SO2Health effects of NO2Health effects of OzoneHealth effects of carbon monoxide Health effects of PM10 and PM2.5Health effects of Lead 
WheezingCoughingHealth effects caused by NO2 includes:CoughingExposure to this toxic gas can irritate your throat and lung linings. impaired vision and coordination, dizziness, confusion, nausea CoughingRunny noseStinging eyesCan decrease the kidney functionCause reproductive problems    
Shortness of breathWheezingShortness of breathCauses difficulty in breathing angina, impaired vision and reduced brain function.  WheezingCoughingBehavioural and hearing problems in children 
People having existing lung conditions are more prone to its effects. It can worsen the condition of people with lung conditions.The people at higher risk includes; children, elderly, and people with lung conditions.fatigue in healthy people and chest pain in people with heart    diseaseChest tightness,Difficulty in breathing Anemia in children 

How can we limit our exposure to the harmful pollutants

Check for ground level Ozone Pollution

When the ground level Ozone concentration increases, it leads to poor air quality. With the increasing ozone levels the outdoor exertion level should be planned accordingly. 

However the normal physical activities can be performed indoors under controlled conditions like air conditioners and air purifiers when ozone concentrations are high outside. 

Plan any outdoor activity in morning 

During early mornings, the ozone concentration is lower as compared to mid afternoon. So you can plan your activities in the mornings.However,  If the AQI has reached to harmful levels you can schedule your outdoor activities to the next day. 

Check for particle pollution concentration: 

Particle Pollution (PM2.5): when the concentration of PM2.5 is high in the ambient air, the air quality both outdoors and indoors gets affected. In this case the amount of physical activity should be limited. 

In such a case, installing air purifiers and HVAC systems will improve the indoor air quality. 

Given below are the links of few air purifiers that will keep your house clean and safe:

Air purifier : Germ Guardian Air Purifier

  • Features: Germ guardian 5 in 1 air purifier is an electrostatic HEPA air filter and offers a removal efficiency of about 99.97% against particles as small as 0.3 microns. 
  • Efficiently removes harmful germs like viruses, odor causing bacteria, mold spores, mildew, and other allergens like;  dust, pet hair, and other large particles; like PM10
  • The efficient UV-C light kills airborne viruses such as influenza, staph and rhinovirus. 
  • The filter also removes the VOC concentration with the help of titanium dioxide. 
  • The activated charcoal filter is effective against cooking odor, tobacco smoke, fumes, pet odor etc. 
  • Offers quiet operation; with the Ultra-quiet sleep mode it operates on low sound levels to get you a good night’s sleep.  
  • GermGuardian Air Purifiers are ideal for medium to large rooms having an area of about 743 sq ft.

Air purifier: Instant Air Purifier

  • Features: Instant air purifiers are proven to kill 99.9% of Covid-19 virus, bacteria, mold, and other harmful viruses. 
  • With its Advanced 3-in-1filtration; HEPA-13, Activated Carbon, Antimicrobial coating and plasma ion technology it removes 99.97% of pollutants like particulate matter tobacco smoke, pet dander, certain odors and other impurities. 
  • Its advanced sensors offer a 24×7 air quality monitoring with auto fan speed adjust feature.
  • It filters the air in an area of 126 sq ft 5x per hour 
  • With its whisper quiet night mode it offers lower noise for a sound sleep.
  • The filters last upto 8 month, after that it needs to be replaced.

Air purifier: LEVOIT Air Purifiers for Home

  • Features: You can access this device from anywhere, fan speeds can also be operated through your smartphone. 
  • Better purification with its 360 degree design. Suitable for large rooms. 
  • It has an ultra fine nylon pre filter and activated carbon filter. 
  • Highly efficient against 99.7% contaminants for particles as small as 0.3 microns such as; dust pollen, pet hair, mold, odor etc. 
  • Does not make much noise
  • Voice control feature 

Air purifier: TOPPIN HEPA Air Purifiers for Home

  • Features: Efficiency of about 95% for particle size of 0.3 microns. 
  • It has UV light, carbon filter and nano silver filter coating. 
  • Highly efficient against airborne contaminants; dust, pet hair, pollen and also efficient against odors, tobacco smoke etc. 
  • Fragrance sponge and aroma diffuser are also present.
  • Purifies a large area of upto 160 sq ft
  • Low noise levels.
  • UV lamps are covered to avoid direct eye contact

By installing an HVAC systems 

The HVAC system works efficiently towards filtering airborne contaminants and also helps in continuous circulation of air.

Given below are the links of few HVAC systems that will keep your house clean and safe:

HVAC System:  Honeywell F300E1019 Electronic Air Cleaner

  • Features: This can be operated with gas, oil and AC systems. 
  • Efficiency for capturing particles is upto 98%.
  • Has a very low pressure drop

HVAC System: DAIKIN Inverter Air Conditioner Heat Pump System

  • Features: Daikin’s ductless technology offers  greater  energy efficiency; cools and warms up the room fast.
  • Smart inverter technology with integrated inverted variable speed compressor
  • Provides continuous heating and cooling with minimum temperature fluctuations.
  • Quiet operation; with indoor sound levels as low as 37 decibels. 

Keep a check on overall air pollution levels

You can keep a check on the air quality index of your area to get insight about the pollution levels. There are certain websites designed for this purpose such as the Environmental Protection Agency. These sites can be accessed anytime of the day.

You can also get information from local radio, television, and newspapers. This way you can plan your outdoor schedule accordingly. 

Avoid outdoor trips during the peak hours

Avoid going outdoors during the peak hours of pollution. Air pollution levels are highest in the afternoon, so try not to go outside at that time. Doing so can increase the chance of getting exposed to high levels of pollution. Avoid outdoor exercising when the Air Quality Index is greater than 300. 

Avoid going to high-pollution areas

Pollution levels are the highest near the roadways especially within 1/4 mile of a road. Highly congested urban areas and smoking areas should also be avoided. 

Using fans for the improvement of air flow indoors 

If opening windows are not feasible consider using bathroom and stove exhaust fans. Try placing the fans close to an open window or a door. This ensures better air circulation and draws the air borne particles like viruses, bacteria and particulates out of your house.

Below are the best exhaust ventilation and for improving the air flow in your room:

Fan: AC Infinity AIRLIFT Exhaust Fan

  • Features: Offers high airflow; draws out heat, moisture, odor, and dust etc.
  • EC-motor with PWM-control increases and reduces energy consumption and noise levels (67dB)
  • Blades are made of aluminum that are resistant to liquid and dust

Fan: VENTISOL Variable Shutter Exhaust Fan

  • Features: Provides superior airflow; ideal for  garages, gardens, attics, barns, greenhouses, basements etc.
  • Easy installation consists of hard wire connection for wiring.
  • Body made of galvanized steel frame, 3 aluminum shutter blades, fully enclosed ball bearing motor, self closing shutter system provides protection to fans when not in use.
  • It’s suitable for ventilating a building to the outside.
  • Powerful & Efficient: 120 volts at 70W, 0.57 amps, with 1680rpm


Use of evaporative coolers 

Evaporative coolers are also known as swamp coolers. They help in increasing the ventilation in the room and also cools down the indoor air. Evaporative coolers are ideal for dry climates. They require water to provide cooling and also enhances the relative humidity of the room.

Below are some links to the best evaporative coolers that offers better airflow for your room:

Evaporative cooler: Pro Breeze Evaporative Air Cooler 

  • Offers powerful cooling with its  waterfall cooling technology that propels air through an ice cold honeycomb filter.
  • A portable swamp cooler air conditioner ideal for room, home office or bedroom.
  • This is a 3-in-1 appliance which can operate as an air cooler, a cooling fan and a humidifier.
  • It runs at just 0.0065 kw/h, which is much more energy efficient than an air conditioner hence it is energy efficient & cost-effective

Evaporative cooler: Air Cooler Sunday Living

  • This swamp cooler has a double layer water circulation system which purifies air can also be used as a humidifier or a fan
  • Water tank has a large capacity with visible water level window 
  • This cooler does not have compressor and chemical refrigerants and hence it is environmental friendly 
  • Comes with a bladeless cooling solution 
  • Cost effective Compared with your costly AC,
  • Safer to use in the household that has children or pets.

Other FAQs about Air Quality that you may be interested in.

What air quality should you stay indoors?

What air pollutants scare lungs?

Should windows be closed at night?


So, in this article we discussed what AQI is unhealthy. And what measures we can take to protect ourselves from the impact of harmful pollutants. We hope you found this article helpful.