A Noob’s Guide to PM 2.5, PM 10 & Air Quality Index (AQI)

PM 2.5, and PM 10, we keep on hearing these two words whenever we talk about air pollution. As an Environmental Biotechnologist myself, I feel I should make everyone aware of these because they need our serious attention.

Rapid urbanization and human activities have led to the rise of Air Pollution levels in the recent era. We are exposed to harmful PMs or particulate matters every day that are carried by air. They remain suspended in air, so they are often called SPM or Suspended Particulate Matter too.

They blur your visibility. This is Delhi. (image below).

PM 2.5 and PM 10: Why should you be concerned?

In today’s post, we will learn the following:

Well, if you google these terms, you will find lots of scientific articles explaining these in detail. I don’t intend to write one such post. I wrote it in a simple way which is easier to grasp, even for people without a scientific background. So, let’s get started!

What is Particulate Matter? And why should you be Concerned?

Well, anything that has a mass and takes up space is called matter. Particulate Matters are matters in the form of minute particles. Well, how minute? To give you an idea, it can be twenty times thinner than a single hair in your body. That’s how tiny it is.

All solid and liquid, organic, and inorganic particles contribute to Particulate Matters. They may contain dust, smoke, aerosols, fly-ash, pollen, soots, fumes, mists, airborne fungal spores, and more. Most of these can be sourced from vehicular emissions, industrial emissions, stubble burning, and more. But there may be natural sources too, such as forest wildfires, volcanic eruptions, etc.

Now that you have a fair idea about particulate matters, let’s move on to their terminology.

What are PM 2.5 and PM 10?

Particulate Matters are classified into two types: Coarse PM and Fine PM, depending on their size.

Coarse PMs range between 2.5 – 10 μm, also called PM 10. Fine PMs range 2.5 μm or below, also called PM 2.5. Btw, those who don’t know, ‘μm’ stands for a micrometer or, 1×10^-6 m.

Just a simpler conversion: 1 mm = 1000 μm. And we are talking about 2.5 μm, so you can well understand how small it is. Human eyes can neither perceive it, nor your nostrils can filter it while you breathe in.

PM 2.5 and PM 10: Why should you be concerned?

Source: Blissair.com

The sources for particulate matters can be both natural and human-made.

PM 2.5 and PM 10 can come from the dust surrounding construction sites, landfills, and agricultural sites. It may originate from the combustion process in the power plants, smokes from wildfires, waste and stubble burning, vehicular emissions, and motor combustions, and industrial emissions that include oxides of sulfur, nitrogen and various VOCs (Volatile Organic Compounds).

How does PM 2.5 and PM 10 enter the Human Body?

Let’s now explore the impact of particulate matters on human beings.

Well, you must have come across pictures of people burning firecrackers with face-masks on, especially in Delhi areas. You might also notice a lot of people using the standard cloth masks, which retails for Rs20 to Rs30 in local shops and public transports.

The irony is, those cheap masks cannot filter out the PM 10 or PM 2.5, because they are smaller than the pores inside that mask. All it does is to protect the person from the thick dust.

But guess what?

Our human body is already designed to protect us from that. Your nostrils have nasal hairs and mucous, which blocks all such particles, and well, you get rid of them when you pick your nose.

When the PM 2.5 particles are in excess in the air, it irritates your eyes, nose, and throat.

Imagine yourself burning a heap of leaves and then inhaling in the thick, dense smoke. Don’t you feel irritation in your eyes and nose? That is due to tiny particles that are going inside your nostrils.

So, if there are excess particulate matters in the ambient air, it is advised to stay inside, avoid outdoor activities, and use an N95 or N99 face mask while you travel outdoors.

Our nose can filter up to 90% of PM 2.5 particles. But the rest still manages to get inside your body. And that’s sufficient to cause damage.

Once you inhale, toxic particles will enter your body via your nostrils and throat, and goes straight to your lungs.

Our lungs are like a vacuum cleaner. It filters out Oxygen from the air we inhale and supplies it to our Red Blood Cells (RBCs).

The PM 2.5 particles are so tiny that it cannot be adequately filtered, and it manages to enter your blood. At first, it reaches your heart, since it is our blood-pump, and then, it reaches other organs of our body from there via your blood.

Just think, every cell of your body is taking up PM 2.5 particles every time you inhale toxic air. And once it is inside, it is trapped there. It remains in your body forever. There is NO PROCESS to bring it outside.

Impact of PM 2.5 inside Human Body:

As the lungs and heart get affected the most by the particulate matters, it causes cardiovascular diseases like asthma, bronchitis, emphysema. It may even cause lung cancer (due to DNA Mutations deep inside a cell).

The thing is, our body is designed to protect us. Naturally, it will try to prevent or eliminate foreign bodies as soon as it enters your body. Hence, initially, in the short-term, you won’t feel a thing.

It will gradually cause you discomfort, then coughing, breathing trouble, chest tightness, later respiratory problems, and finally, cardiovascular issues, stroke, or cancer. It is a perfect example of slow poisoning.

I don’t intend to frighten you, but my aim is only to make you aware of the harmful effects of particulate matters around us. It’s time you understand the long term impacts and minimize the activities that generate these particles.

Check out this infographic from Harvard. (click the image to zoom in)

PM 2.5 and PM 10: Why should you be concerned?

Source: Harvard

What is Air Quality Index?

Air Quality Index is a unitless number that signifies the air-pollution level of a particular place, in terms of particulate matters, oxides of sulfur, nitrogen, and ozone, and other air pollutants. It is calculated using the concentration of an air-pollutant on a place over a period, which is obtained from an air-quality monitor. It has a complex computation, which I won’t go into many details.

In major Indian cities, the Air Quality Index is provided by the Central Pollution Control Board (CPCB) and the respective State Pollution Control Board (SPCB). In many places, an additional AQI is supplied by the US Consulate, since they have also placed an air quality monitor in their respective US Embassies.

Here’s the common AQI Chart we all refer to.

51-100Minimal Discomfort to Sensitive People (Children/Old)
200-300Poor (Breathing Discomfort to Most People)
300-400Very Poor (Respiratory Illness on Prolonged Exposure)
400-500Severe (Healthy People will get Respiratory Diseases)
500+Hazardous (You should leave the region immediately)

Well, here’s a perspective, in 2019, the AQI levels in New Delhi during Diwali shot to 999. The actual count may be much higher since 999 is the maximum measurable limit for the air quality monitors. So, you can pretty much get the idea of the extent of hazard it caused to the people.

How to find out the AQI of your Region?

Many online data providers provide the Air Quality Index of any region. I prefer AirVisual as it is noob-friendly and takes minimal resources to load. It shows the air quality of any area in the world, via crowdsourcing. You can see the top 10 places in the world with the worst air quality in real-time. It also provides an Air Quality monitor, which you may purchase if you want to, and contribute towards mapping the air quality further in your region.

PM 2.5 and PM 10: Why should you be concerned?

You can check out AirVisual here: Website | Android App | iOS App.

How to prevent yourself from PM 2.5?

So, I have talked about particulate matters, and also how to check the air quality index of your area. But, you may want to know how you can prevent yourself from getting exposed to PM 2.5.

Well, you cannot entirely stop the anthropogenic activities leading to the generation of particulates. I mean, you cannot only shut down industries, or stop taking motor vehicles. It is inevitable.

What the industries are doing right now is to check their emissions, and purify them before releasing them into the environment. They use a gas scrubber, an air pollution control mechanism aimed at reducing particulates or harmful gases such as ammonia or chlorine from the industrial exhausts. It uses a liquid spray over the gaseous exhaust, which traps some of the particulates from the gas into the liquid.

The motor vehicles are trying to adhere to emission standards known as Bharat Stage Emission Standards or BSES. They are employed by Govt of India to regulate the output of air pollutants from vehicular combustion engines. Currently, the Bharat Stage VI is in enforcement in 2020, and the Supreme Court has already ordered a ban in the sale of vehicles with BS-IV or lower from April 2020.

But even after doing so much, you might get exposed to PM 2.5 anyway. Just check your region AQI. If you find yourself in a neighborhood with an AQI higher then 100, then you should consider using a mask.

And no, don’t use the typical cloth masks that retail for Rs20-30. They are of no use, and your body filters air better than them.

Only stick to N95 or N99 masks. N95 and N99 are standard masks having filters that can purify 95% and 99% of PM 2.5, respectively. I wrote a detailed post regarding the Best N95 and N99 Anti-Pollution Masks to wear for effective PM 2.5 protection. You may check it out for more insights.

Last Words:

I hope I was able to clarify all your doubts regarding PM 2.5 and PM10. In my entire post, I put greater emphasis on the former because they are smaller in size and pose more significant threats. If you can protect yourself from PM 2.5, you will automatically stay protected from PM 10.

That’s all about Air Pollution standards. Thank You for reading until the end. If you have further queries, feel free to comment below. I will happily help you out.

This is the first time I have tried posting something out of our usual posts on technology. Hence I have put this post in a separate science and tech category. If you love reading our posts, then don’t forget to share them with your friends. Use the social share buttons.

I will be back again with another exciting update. Till then, stay tuned!

Nirmal Sarkar

Nirmal Sarkar is a Biotechnologist from the city of Joy, Kolkata. He is the founder of this blog and covers a wide range of topics from Gadgets to Software to Latest Offers. You can get in touch with him via nirmal@hitricks.com

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