What Air Quality Index Level Is Safe, & How Is It Measured?

In this guide, we discuss:

– What air quality index level might be safe to breathe in and live in

– How it’s measured and tracked

– How to understand it/check it

 

Summary – Air Quality Index Levels

What Is Air Quality?

In simplified terms, it might be an indicator of how clean air is, and how safe it might be to breathe 

 

How Is Air Quality Measured? – Using An Air Quality Index

Air quality is generally measured with an Air Quality Index for a particular geographic area, like a State or a city

A scale with low through to high values is used for the Air Quality Index

The scale may indicate how good or poor the air conditions are, but also what the health implications of going outside are at the current air quality level (or, there can also be precautions and actions suggested for each value along the scale)

Different indexes may measure different pollutants (like particulate matter specifically for example), so check what the index includes and doesn’t include

 

Factors That Can Impact Air Quality

The rate or amount of air pollution in an area obviously has a significant impact on air quality

But, there’s a range of other factors that can impact air quality in the short term. We list those potential factors in the guide below

It’s worth pointing out that air quality can change over time – day to day, week to week, and over longer period

So, real time air quality is one of the more accurate measurements available

 

Different Air Quality Indexes

Different countries, and different cities and States may use different Air Quality Indexes

Refer to the local Air Quality Index to see which one is used in the area you are living in

 

What Air Quality Levels Are Safe?

Generally, the lower values on each Air Quality Index indicates better air conditions, and lower risk of health issues, and might be safer

Having said that, each Air Quality Index indicates what the values on their scales mean, and also how to interpret their scales, and these instructions should be followed to determine a safe air quality level

 

Guidelines For Safe Air Pollution Levels

WHO indicates what ‘safe’ air pollution concentration levels might be for each major air pollutant where those who are breathing in the air might be at a reduced risk of health issues

We’ve summarised those concentration levels in the guide below 

 

Examples Of The Air Quality In Different Regions In The World Right Now

We’ve included some examples in the guide below

 

What % Of Cities Worldwide Might Have Acceptable Air Quality Levels

In this guide, we outline what % of cities might have air quality levels within acceptable guidelines, when considering the concentration of particulate matter in the air

 

How To Find Out The Air Quality In The Area You Live In

We’ve included some potential steps to do this in the guide below

 

What Is Air Quality?

A very simple way to explain air quality might be how clean the air is in a particular area

It’s a general measure of how much or how little air pollutants are in the air 

Air quality can be an indicator of what level or risk/harm breathing in that air might involve

 

How Is Air Quality Measured? – Using An Air Quality Index

Air quality is generally measured by measuring the concentration or amount of different air pollutants in the air in a particular geographic region

The different major pollutants measured can include one of the following – ozone, particulate matter (PM2.5 and PM10), carbon monoxide, and sulfur dioxide.

Some may measure nitrogen dioxide as well.

Air quality is expressed on an Air Quality Index scale with different values

Generally, the lower the value on the index scale, the less hazardous the air is to breathe in, and the safer it is to go outside and breathe in the air. The same can be said vice versa for higher values on the index

Each different index in different geographic areas gives people looking at the index instructions on how to use the index

Those reading an index should also be aware of factors such as what pollutant the index measures (some just measure particular matter for example), and if the index is for the current day (amongst other factors)

Different air pollutants can have different potential impacts on human health and pre existing conditions as well, so, this is something to be aware of too

 

Factors That Can Impact Air Quality 

Air quality can change day to day, and over longer periods too. 

Obviously a major factor that impacts air quality is rate of air pollution in the area, and the concentration of air pollutants in the air.

But, short term changes in air quality levels can also be impacted by:

– Weather

From OurWorldInData.org:

[There is a factor that has an] impact on pollution concentrations over time and space: the weather.

Local weather conditions, and seasonal and weather patterns have an important influence on the year-round fluctuations in exposure levels reported in each place

– Wind

– Temperature and sunlight 

– Rainfall

– Wildfires (a changing climate is predicted to increase the risk of wildfires)

 

These factors can increase or decrease the concentration of different pollutants in the air in the short term.

Other factors like the ability of trees and vegetation to help purify air can also impact air quality

Additionally, there’s several ways that air pollution can be addressed by cities

 

What Air Quality Index Does Each Country & Region Use?

There are large online global sites that keep track of the Air Quality Index (such as WAQI, Airnow and AQICN), and individual governments in countries and cities also have their own tracking programs.

 

United States

[In the] U.S., the Environmental Protection Agency (EPA) created the Air Quality Index (AQI) to monitor and report on air quality each day and let people know about its possible health impacts (blogs.ei.columbia.edu)

 

Australia

The NSW Government in Australia has their own air monitoring networks where they measure particles (PM10, PM2.5), sulfur dioxide (SO2), carbon monoxide (CO), ozone (O3), nitrogen dioxide (NO2) and visibility. 

 

Other Countries

Other countries may use other air quality/air pollutant indexes to measure air quality.

For example, Canada might use the Air Quality Health Index (Canada), Malaysia the Air Pollution Index, and Singapore the Pollutant Standards Index

 

States, Provinces & Cities

Individual States, Province & cities may use their own local indexes and air quality scales, so, check these online for the place you live or are visiting in as well.

 

What Air Quality Index Levels Are Safe To Breathe In?

The answer to this question is to look at the air quality index for the area you live in.

Most indexes provide two indicators to determine along the scale:

1. An indicator of how polluted or clean the air might be for each value on the scale

2. An indicator of potential health effects of breathing in the air for each value on the scale, or, recommended precautions or actions for each value

But obviously, the cleaner the air and the lower the concentration of pollutants in it, the less hazardous it might be to breathe in.

It’s possible groups of people, like children, people with respiratory conditions, very active outdoors people, and some elderly people might be more at risk of poor air quality

 

We’ve compiled scales and values on those scales from different air quality indexes used in different places around the world below.

From these scales, some values of safe air quality might be (obviously though, confirm and check these values yourself):

– For the US AQI index, somewhere between 0 to 100 is probably safest.

– In Australia, in NSW, somewhere between 0 to 66 is probably safest.

– For the world index, somewhere between 0 to 100 is probably safest.

 

United States Index

From airnow.gov, the US AQI lists the following indicators (along with color coding for each):

Air Quality Index Value/Range, & Air Quality:

0-50 – air quality conditions are good

51-100 – air quality conditions are moderate

101-150 – air quality conditions are unhealthy for sensitive groups

151-200 – air quality conditions are unhealthy for everyone

201-300 – air quality conditions are very unhealthy for everyone

301-500 – air quality conditions are hazardous for everyone

 

From airnow.gov, the potential health implications of the above values might be:

0-50 – Air quality is considered satisfactory, and air pollution poses little or no risk.

51-100 – Air quality is acceptable; however, for some pollutants there may be a moderate health concern for a very small number of people. For example, people who are unusually sensitive to ozone may experience respiratory symptoms.

101-150 – Although general public is not likely to be affected at this AQI range, people with lung disease, older adults and children are at a greater risk from exposure to ozone, whereas persons with heart and lung disease, older adults and children are at greater risk from the presence of particles in the air.

151-200 – Everyone may begin to experience some adverse health effects, and members of the sensitive groups may experience more serious effects.

201-300 – This would trigger a health alert signifying that everyone may experience more serious health effects.

301-500 – This would trigger a health warnings of emergency conditions. The entire population is more likely to be affected.

 

You can find local air quality at in the airnow.gov resource.

Enter your state and zip code, and press the ‘Go’ button.

 

Australia Index (NSW)

From environment.nsw.gov.au, the NSW AQI lists the following indicators (along with color coding for each):

Air Quality Index Value/Range, & Air Quality Conditions:

0-33 – very good air quality conditions 

34-66 – good air quality conditions

67-99 – fair air quality conditions

100-149 – poor air quality conditions

150-200 – very poor air quality conditions

200+ – hazardous air quality conditions

 

From environment.nsw.gov.au, the recommended precautions or actions for these values might be:

0-33 – enjoy activities

34-66 – enjoy activities

67-99 – People unusually sensitive to air pollution should plan strenuous outdoor activities when air quality is better

100-149 – AIR POLLUTION HEALTH ALERT. Sensitive Groups should cut back or reschedule strenuous outdoor activities

150-200 – AIR POLLUTION HEALTH ALERT. Sensitive groups should avoid strenuous outdoor activities. Everyone should cut back or reschedule strenuous outdoor activities.

200+ – AIR POLLUTION HEALTH ALERT. Sensitive groups should avoid all outdoor physical activities. Everyone should significantly cut back on outdoor physical activities.

 

You can find local air quality by clicking the links for the different regions in NSW at the bottom of the environment.nsw.gov.au site

The air quality values are displayed on each region’s page

 

World Index

From waqi.info, the World AQI lists the following indicators (along with color coding for each):

Air Quality Index Value/Range, & Air Quality Conditions:

0-50 – good air quality conditions

51-100 – moderate air quality conditions

101-150 – unhealthy air quality conditions for sensitive groups

151-200 – unhealthy air quality conditions for everyone

201-300 – very unhealthy air quality conditions for everyone

300+ – hazardous air quality conditions for everyone

 

From waqi.info, the potential health implications of these values might be:

0-50 – poses little to no risk to health

51-100 – for some pollutants there may be a moderate health concern for a very small number of people who are unusually sensitive to air pollution

101-150 – Members of sensitive groups may experience health effects. The general public is not likely to be affected.

151-200 – Everyone may begin to experience health effects; members of sensitive groups may experience more serious health effects

201-300 – Health warnings of emergency conditions. The entire population is more likely to be affected.

300+ – HEALTH ALERT: everyone may experience more serious health effects

– waqi.info

 

waqi.info also provides a cautionary statement for PM2.5:

0-50 – none

51-100 – active children and adults, and people with respiratory disease, such as asthma, should limit prolonged outdoor exertion

101-150 – active children and adults, and people with respiratory disease, such as asthma, should limit prolonged outdoor exertion

151-200 – active children and adults, and people with respiratory disease, such as asthma, should avoid prolonged outdoor exertion. Everyone else, especially children, should limit prolonged outdoor exertion

201-300 – active children and adults, and people with respiratory disease, such as asthma, should avoid prolonged outdoor exertion. Everyone else, especially children, should limit prolonged outdoor exertion

300+ – everyone should avoid all outdoor exertion

 

You can see the air quality index values on the real time map at waqi.info

 

Air Quality Indexes Of Various Other Countries

View at the wikipedia.org resource

 

What Levels Of Each Air Pollutant Are Recommended To Reduce Health Risk?

The World Health Organisation provides guideline concentrations of major pollutants in the air, that are considered more safer or healthier to minimise the risk of disease and health issues.

Another way of saying that is – if all regions had air pollutant levels around these levels, there may be less risk that breathing air in in these regions would lead to health issues.

When checking how much of each air pollutant is in the air in your locality via an online air quality index tracker, you may like to compare the real time values against these values.

These values according to who.int are:

 

Particulate Matter

– Fine Particulate Matter (PM2.5)

10 μg/m3 annual mean

25 μg/m3 24-hour mean

 

– Coarse Particulate Matter (PM10)

20 μg/m3 annual mean

50 μg/m3 24-hour mean

 

Ozone (O3)  

100 μg/m3 8-hour mean

 

Nitrogen dioxide (NO2)

40 μg/m3 annual mean

200 μg/m3 1-hour mean

 

Sulfur dioxide (SO2)

20 μg/m3 24-hour mean

500 μg/m3 10-minute mean

 

Current Examples Of Exposure To Unsafe Levels Of Air Pollution Around The World

Countries With The Worst Air Pollution

Read more about the cities and countries in the world with the worst air quality and pollution in this guide.

 

US States With The Most & Least Air Pollution

In this guide, we look at the US States which might have some of the most and least polluted air.

 

Other Countries & Region

The interactive who.int map in the sources list indicates that ‘91% of the world’s population lives in places where air quality exceeds WHO guideline limits’

Eighty-five percent of European urban dwellers are exposed to particulate matter at levels higher than what WHO considers safe (blogs.ei.columbia.edu)

 

How Can You Check An Air Quality Index & Keep Up To Date With Air Quality In Your Area?

Some of the main steps might be:

1. Do an online search for air quality in your city, town or area. You can perform a search similar to this one ‘Air quality index [insert where you live]’

2. Look for the official real time air quality index in your area (your city or town)

3. Read over the air quality index, and make sure you know what it’s measuring, and what the different values on the scale mean

Some air quality indexes come with maps and other features and tools too

4. Check the index regularly in areas with poorer air quality, and if you want to (and if there’s a feature to), you may be able to sign up for air quality alerts

 

 

Sources

1. https://en.wikipedia.org/wiki/Air_quality_index

2. https://airnow.gov/index.cfm?action=aqibasics.aqi

3. https://www.environment.nsw.gov.au/topics/air/understanding-air-quality-data/air-quality-index

4. https://waqi.info/

5. https://blogs.ei.columbia.edu/2018/06/26/air-quality-alerts-pollution/ 

6. https://www.who.int/airpollution/en/ 

7. http://maps.who.int/airpollution/

8. https://www.who.int/gho/phe/indoor_air_pollution/burden/en/ 

9. https://www.who.int/news-room/fact-sheets/detail/ambient-(outdoor)-air-quality-and-health

Leave a Comment