Complete Guide to Air Pollution (AQI, Dangers, and More!)

Complete Guide to Air Pollution (AQI, Dangers, and More!)

Air pollution is one of the most insidious threats that is quickly becoming more prevalent globally. However, it's also a threat that many of us don't consider for some reason. When was the last time you actively thought about air pollution and the harm that it causes?


If you think we're being overly dramatic, here are a few stats about air pollution that show just how damaging it is. Over 4.5 million deaths were attributed to air pollution last year (1). While 4.5 million is the official number, the actual number is likely significantly more. We'll discuss the reasons why a bit later in this article.


Just under 8% of global deaths are caused by air pollution. That means that approximately 1/12 of deaths are directly attributable to airborne pollutants. This is an incredibly high percentage, and in 2015 air pollution led to more deaths than smoking (2).

Graph from Our World in Data.

According to the WHO, over 99% of the global population breathes air that exceeds the guideline limits for airborne pollutants (3). This suggests that nearly everyone reading this article is at risk of suffering from the consequences of air pollution. 


Despite these worrying numbers, air pollution is still not widely publicised or even considered. While occasionally some cities will make headlines on days of exceptionally high pollutant concentrations, more often than not, air pollution isn't given a second thought.


Yet an ever-increasing amount of research is being published linking air pollution to a massive range of diseases and other health concerns. With all of this information coming to light, it's about time that air pollution gets the attention that it needs.


In today's article, we want to discuss the essentials you need to be aware of regarding air pollution. We will be discussing the health impacts, pollutant sources, how to protect yourself, and more. 


Air pollution is something that requires a coordinated effort to solve. For true change to be made, cooperation is needed on a large scale. However, there are ways to protect yourself, family and friends in the meantime. 



Health Impacts of Air Pollution

Health impacts of air pollution. Image from European Environmental Agency.


Before proceeding further in this article, it's important to discuss why it's so vital that we protect ourselves and our loved ones. The health impacts of air pollution are very severe, but we don't want to generate fear. 


Instead, we feel that it's essential to share the impacts of air pollution on human health to create awareness of the severity of the issue. AirPop was created because our co-founder was passionate that everyone has the right to breathe fresh air. But, unfortunately, in the modern world, fresh air is not a given.


While the health impacts of air pollution that we are about to discuss may seem exaggerated, these findings are based on research. All links to the relevant articles are provided. It's also important to keep in mind that we can take steps to protect our health. So while the impacts are severe, we do have options. 


We can sort the impacts of air pollution on human health into two categories: short-term and long-term. Short-term health issues are those that you are likely to feel when being exposed to or shortly after being exposed to air pollution. Long-term impacts are more dangerous but are likely not to be felt until being exposed to hazardous levels of pollutants for months, years, or more.


The short-term impacts of air pollution can include chronic obstructive pulmonary disease, coughing, shortness of breath, wheezing and more (1). Short-term effects are generally more noticeable in susceptible individuals such as those with asthma. 


The long-term impacts of air pollution can range greatly, and the full implications of air pollution on human health are not yet understood. Furthermore, due to the relatively recent emergence of air pollution as a widespread health concern, many studies are only recently being carried out. 

Risk pyramid. Image from U.S Environmental Protection Agency.

Air pollution's more well-known long-term health effects include chronic asthma, cardiovascular diseases, and mortality (1). However, far more impacts have only been linked to air pollution recently.


A recent study found that everything from fertility to sleep efficiency is decreased as pollutant levels increase. The same study found that air pollution affects every organ in the human body (2).


On top of this, air pollution has been linked to decreased cognitive performance. For example, one study found that air pollution increases the number of mistakes made by chess players on polluted days (3). Another study found that baseball umpires make worse decisions on days of high pollution (4).


While in themselves, these shorter-term effects may not sound too severe, they can have tremendous consequences. For example, an OECD study found that an increase in air pollution can lead to lower GDP as workers are less efficient (5). Moreover, with many cities surpassing air quality guidelines daily, it's easy to see that air pollution is having an enormous impact on not only us as individuals but also society as a whole. 


While some of the dangers of air pollution are more obvious than others, airborne pollutants impact our lives in ways that we don't even know yet. For example, while you might expect air pollution to lead to respiratory issues, you probably wouldn't expect it to be linked to suicide rates (6).


This is what leads to air pollution being such a severe issue. While we know that it's incredibly harmful, we still don't know all of the impacts that it can have on our health. However, what we do know is that we must act on the knowledge that we do have. We need to start informing ourselves about the dangers of air pollution and learn what we can do to avoid the health implications that it can bring.



How Is Air Pollution Monitored?

While it’s essential to know the health implications of air pollution, it’s equally important to understand how to monitor the levels of airborne pollutants. This will allow you to know when you should take protective actions and when it’s best to avoid certain areas or the outdoors altogether. 


Pollutant levels are generally measured and aggregated into a total score, usually on a scale of 0-500. This index is named AQI or Air Quality Index. While some countries use slightly different systems with different hazard levels, most regions integrate ultrafine particles, fine particles, ground-level ozone, sulfur dioxide, nitrogen dioxide and carbon monoxide into their AQI.


The concentrations of these individual pollutants are then aggregated and presented in an overall value. In the U.S, this scale has six tiers which are colour-coded to indicate danger levels. 

AQI Scale as per U.S EPA.


When air pollution levels are green on the AQI scale, air pollution is considered to have little or no risk. When this colour moves to yellow or orange, at-risk groups and sensitive individuals may experience adverse effects.


When the air quality deteriorates further and AQI is shown in red or purple, everyone will feel the short-term impacts of air pollution. During these times, it’s best to avoid going outside where possible. If you need to go out, make sure to don a mask.


Finally, dark brown or maroon is the final step of the air quality index. Usually, these extremely highly polluted days occur during wildfires or other natural disasters. During these times, it’s highly advisable to stay inside wherever possible. Thankfully, most people will not experience AQIs this high. 


As previously mentioned, AQI is an aggregated reading of a range of different airborne pollutants. So if you’re particularly susceptible to the impacts of a specific pollutant, it’s possible to view the individual readings on a range of apps and websites.

What Air Pollution Levels are Safe?

One of the most confusing aspects of AQI scales is that there is a range of different systems. An AQI reading in one country could be considered 'safe', whereas the same reading in a different country could be regarded as 'hazardous'. 


For example, the NAQI is the AQI scale widely used in India. This scale is far more forgiving than the scale used by the U.S Environmental Protection Agency - a day that is unhealthy for sensitive individuals according to the EPA scale could be considered satisfactory by NAQI (1).

U.S EPA AQI vs NAQI. Image from Smart Air filters.

For this reason, using AQI scales alone isn't ideal. While a bit more complex, it's worth looking into the concentrations of individual pollutants using websites such as AQICN. From this information, you will be much better informed about the dangers and when you need to protect yourself.


So, what pollutant levels are considered safe? According to WHO guidelines, the safe levels of pollutants are as follows (2):

Fine particulate matter (PM2.5)

5 μg/m3 annual mean

15 μg/m3 24-hour mean

Coarse particulate matter (PM10)

15 μg/m3 annual mean

45 μg/m3 24-hour mean


100 μg/m3, 8-hour daily maximum

60 μg/m3 8-hour mean, peak season


10 μg/m3 annual mean

25 μg/m3 24-hour mean


40 μg/m3 24-hour mean 


These values may seem surprisingly low. However, considering that over 99% of the global population lives in low-quality air, this makes more sense. Using a platform that monitors individual pollutant concentrations, you will be able to identify exactly when a mask is required and also when it's best to avoid the outdoors altogether.



Local Air Quality

A common misconception that we run into is that air conditions are city-wide or region-wide. However, this is far from the truth. Air quality conditions can vary greatly, even from street to street. This is called local air quality, and it’s a term that you will encounter a lot when considering air pollution. 


One of the biggest contributors to local air quality is vehicles. Both stationary and mobile vehicles emit toxic chemicals that stay airborne for long periods. For this reason, one of the best ways to protect yourself from the worst of air pollution is to avoid busy roads and intersections.

These tend to be far more polluted than lesser-travelled side roads, even if these roads are only a couple of hundred metres away. So unless your car is equipped with filters capable of filtering oil-based aerosols, you will still be exposed to these toxic pollutants while inside.


While vehicles are the biggest contributor to differing local air pollution conditions, other factors can play a part too. For example, constructions, commercial cooking, wood burning, generators, and more can contribute to local air pollution levels (1).

Ideally, it’s best to stay away from these pollution hotspots. While this isn’t always possible, it’s essential to be at least aware of the dangers they pose. 


If you’re particularly interested in monitoring and managing local air pollution levels, it might be worth investing in a personal pollution monitor. While these aren’t as accurate as government monitoring stations, they can provide a good indication of when air pollution levels exceed their safety guidelines.


These monitors can be purchased as mobile monitors that you can attach to a backpack or otherwise carry around or as home monitors. You can mount these monitors somewhere on the outside of your home, and they provide semi-accurate ambient air quality readings for your immediate surroundings.



How Can We Protect Ourselves from Air Pollution?

Being aware of air pollution is an important first step. However, it's just that - a first step. To apply the knowledge and protect ourselves, it's vital to ensure that we know what steps we can take.


When it comes to air pollution, it's essential to consider the pollutants individually. However, as a general rule, the best way to protect yourself is to avoid high pollutant concentrations altogether. This is because even the highest-rated 'standard' respirators such as N100s do not provide filtration against gaseous particles.


Therefore, respirators are highly effective against particle pollution such as PM1, PM2.5 and PM10 but not effective against gases such as carbon monoxide, nitrogen dioxide, sulfur dioxide and other VOCs (volatile organic compounds) (1).


While some larger half-face and full-face respirators can filter these gases with specific filter cartridges, these devices are far heavier and more challenging to wear in day to day life. Some certified filtering facepiece respirators (such as typical N95 devices) add carbon filters to filter some VOCs. However, these filters' effectiveness varies greatly and they shouldn't be relied on to filter harmful gaseous pollutants. 


With that being said, most of the health dangers of air pollution have been directly attributed to fine particle concentrations. Therefore, even though FFRs (filtering facepiece respirators) are ineffective against gaseous pollutants, they still protect against the most harmful pollutant - fine dust.


For this reason, it's crucial to consider the exact air pollution concentrations on a given day. For example, if fine dust largely contributes to high levels of air pollution, the best method is avoidance, followed by donning a capable respirator. On the other hand, if gaseous pollutants make up a large part of the overall air pollution, try to stay inside wherever possible. 


Another easy way to reduce your exposure to air pollution is to avoid exercising outdoors when pollution levels are high. Since we inhale more air when active, exercise is a particularly high-risk activity during high pollution days. So, if possible, find an indoor venue or avoid exercise until pollution levels are lower.


It's also important to remember that air pollution can impact you even when you are in an enclosed space. If you regularly drive along busy highways or other high-concentration areas, consider installing a HEPA filter on your cars ventilation system. Many newer vehicles will come with such a system preinstalled.


When inside, make sure to close windows and reduce points where air pollution can enter your home. If the pollution regularly exceeds guidelines, it may be worth considering an air purifier. While some of these devices perform questionably, many have been proven highly effective at reducing indoor air pollution levels. 


Although indoor air pollution is deserving of its own article, it's important to keep indoor pollutant emissions low on days of high pollution. You don't want to be locking your house up to maintain clean air only to have pollutant sources within!


Try to minimise gas usage along with chemical products. Many cleaning products, nail polishes, deodorants, and more contain a range of VOCs that can be detrimental to our health. Mainly, be careful of open fire sources if you live in a house with a fireplace. 


When Should I Wear a Mask?

Unfortunately, there is no easy answer to this question. With many countries and organisations providing different guidelines, it’s hard to judge precisely when a mask is needed. For the best advice, we recommend checking with your doctor.


However, generally speaking, at-risk individuals should be donning masks when fine dust concentrations surpass the WHO safety guidelines. Following the U.S AQI system, masks are recommended for at-risk groups during 101-150 AQI (orange) and over. However, some individuals may feel the impact of air pollution at moderate (51-100, yellow) AQI levels and should consider donning a mask earlier.

If you bike, walk, or otherwise physically exert yourself, then it’s worth donning a mask even on days of moderate air quality. This is especially true if you bike to work along busy roads or highways. However, if this is the case, you might want to consider investing in a half-face respirator capable of filtering vehicle emitted gaseous particles also.


Where possible, we recommend following the U.S AQI system and donning a mask when the pollution levels are unhealthy for sensitive groups. While the WHO recommends donning a mask at lower pollution levels, this can mean wearing a mask every day in most cities worldwide. On the other hand, AQI scales such as the Chinese system are too lenient and consider an AQI of 100 ‘lightly polluted’.


Therefore, while ideally, the WHO pollutant concentration guidelines should be followed, they may be too strict for many people. If you are okay with donning a mask most days (or all days, depending on where you live), follow the WHO system. If you want to allow for more leniency, follow the U.S (EPA) AQI system.

What Masks Should I Wear for Air Pollution Protection?

When it comes to days of high fine dust concentrations, it’s vital to ensure that you have masks ready. However, how can you decide which device is best, and how can you verify that they are protecting you?


The first thing to look for is the certification that a mask holds. The most common certificates are N95, KN95, KF94 and FFP2. All of these certifications are roughly equivalent but are from different regions. For example, FFP2 masks are more common in the EU, whereas KF94 masks are more common in South Korea.


N95, KF94 and FFP2 masks have databases that can be used to check for the authenticity of a device. While there is no such (easily accessible) database for KN95 devices, it’s possible to check the certifications of many devices as they will be displayed publicly on the manufacturer’s website.


While there are higher filtration masks available - such as N99, KN100 and FFP3 - these devices often sacrifice some comfort in the form of breathability. While these devices will provide better protection (assuming they fit correctly), they can be hard to wear in daily life if they have poor breathability.


As such, it’s essential to find a mask that balances filtration, fit and comfort. At AirPop, we designed our masks with all three of these pillars in mind. As a result, our masks are certified KN95 and provide filtration in excess of the standard. They are also highly breathable and comfortable to wear even after long periods. 


Another factor to consider is the lifespan of a mask. When used for air pollution, many masks can be used for days before needing replacement. However, each mask differs slightly, and it’s essential to check the manufacturer’s guidelines to judge how often the device needs to be replaced.


For air pollution especially, reusable masks with replaceable filters are a fantastic choice. These masks tend to be cheaper in the long run and are also more environmentally friendly. Most importantly, there are many capable reusable masks with high filtration!


Air Pollution is a threat that has relatively little awareness despite being very dangerous. At AirPop, we’ve always made it our goal to bring awareness to the health impacts of air pollution and draw attention to the issue.


Unfortunately, while air pollution is dropping in many cities worldwide, it’s becoming increasingly dangerous in other cities. Air pollution is not something that we can afford to overlook. 


We hope this article has given you the knowledge you need to understand and protect yourself from air pollution. If you have children in your family, we recently put together an article addressing air pollution and its impacts on children. Furthermore, we also discussed how you can choose the correct mask for your child - a task that can be incredibly hard!

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