Air pollution, worst affected regions/cities of the world, its reasons and preventions:

What is air pollution?

When any physical, chemical, or biological material mixes with the natural atmosphere and harms nature and humans, it is called air pollution.

If any one or more pollutants like dust, fumes, gas, odor, smoke, or vapor contaminate the atmosphere for a certain period or quantity. It is harmful to human health and is called air pollution.

Smog is a type of air pollution containing smoke, fog, and other pollutants that reduce visibility.

Air pollution may be in any form: solid, liquid, or gas.

It may be man-made or natural.

Natural air pollution is generally produced by natural processes like the eruption of volcanoes, or abnormal processes like the combustion of fossil fuels, etc.

Man-made air pollution is produced due to various productions and waste.

It is a silent killer and is on the rise due to urbanization and industrial growth.

Reasons or sources of man-made air pollution: There are various reasons or sources of air pollution, however, some are listed below:
Combustible engine-operated household devices.	Industrial pollution: Fossil fuel-based industries.
Farming and Agricultural Process	Waste management process
Cooking and heating methods	Power generation
Automobile pollution: Petrol and diesel-operated motor vehicles (road, sea, and air transport).

What are pollutants? Various physical, chemical, and biological agents are responsible for air pollution. Such agents are called pollutants, which are harmful to nature and human health. Some of the pollutants are listed below:
Particulate Matter (PM)	Carbon Monoxide (CO)
Ozone (O3)	Nitrozen Dioxide (NO2)
Sulfur Dioxide (SO2)	Lead (Pb)
Ammonia (NH3)	Benzene (C6H6)
Arsenic (As)	Nickel (Ni)
Suspended Particulate Matter (SPM) or Particulate Matter (PM): Exposure to this pollutant has a strong negative impact on health. Fine particles called SPM2.5 (diameter smaller than or equal to 2.5 micrometers) can easily penetrate blood cells and impact various body parts. The major components of PM are listed below:
Nitrates	Ammonia
Sodium Chloride	Black and elemental carbon
Mineral dust	water
Sulfates	Ultrafine particles
Particles from dust and storm
Black carbon (sooty particles) are fine pollutant particles (SPM2.5 = diameter less than or equal to 2.5 micrometers) emitted from the inefficient combustion of fossil fuels. Methane is also emitted as a pollutant gas from inefficient stove combustion. These are powerful Short-Lived Climate Pollutants (SLCPs).
Carbon Monoxide (CO): It is a tasteless, odorless, colorless toxic gas which is produced by the incomplete combustion of carbonaceous fuel like:
Wood	Petrol
Diesel	Charcoal
Natural gas	Kerosene
Ozone (O3): It is different from the Ozone layer in the upper atmosphere. It is produced in the atmosphere near the ground due to a reaction with gases in sunlight. It is one of the major parts of photochemical smog.
Nitrozen Dioxide (NO2): Industries and transport systems mostly produce this gas during the combustion of fuel.
Sulfur Dioxide (SO2): It is a colorless gas with a pungent, sharp, suffocating, and irritating odor like a burnt match. It is produced during the combustion of fossil fuels like coal and oil. It is also produced when a mineral ore containing sulfur is heated beyond its melting point (called the smelting process)  to extract the metal or its simple compound.

What are the diseases caused by air pollution?
Outdoor (Ambient)  and indoor (household) air pollution causes various diseases, especially those related to the respiratory system. Air pollution mainly enters our body through the respiratory tract, negatively impacts various body parts like the lungs, heart, brain, etc., and causes various diseases. Diseases caused by air pollution are one of the main reasons for morbidity and mortality. Some of the diseases caused by air pollution are listed below:
Ischemic heart disease (cardiovascular)	Lung cancer
Lower Respiratory Infection, Chronic Obstructive Pulmonary Disease (COPD), Asthma, Bronchitis, etc.	Gastrointestinal diseases
Neurological disorder (stroke)	Liver problems
Kidney problems	Skin diseases

Measurement of pollution level: Pollution level is measured with the Air Quality Index (AQI) and divided into various slabs and color codes. It is explained below:
AQI	Pollution level, its color, and advisory
0-50	Good (green color) Advisory: None
51 - 100	Moderate (yellow color) Advisory: Sensitive individuals should limit prolonged outdoor exertion.
101 - 150	Unhealthy for sensitive groups (orange color) Advisory: Children, physically active people, and people suffering from respiratory problems should limit prolonged outdoor exertion.
151 - 200	Unhealthy (red color) Advisory: Children, physically active people, and people suffering from respiratory problems should avoid outdoor exertion. Other persons should limit prolonged outdoor exertion.
201 - 300	Very unhealthy (purple color) Advisory: Children, physically active people, and people suffering from respiratory problems should avoid outdoor exertion. Other persons should limit outdoor exertion.
>300	Hazardous (maroon color) Advisory: Everyone should avoid all physical activity outdoors.

Pollution  or Air Quality Index (AQI)  in the most polluted cities of the world:
City	Pollution level (AQI)
Delhi (India)	224 Note: Post Diwali festival (31/10/2024), AQI in some suburbs of  Delhi NCR crossed the level of 900.
Beijing (China)	179
Lahore (Pakistan)	176
Dhaka (Bangladesh)	163
Wuhan (China)	160
Tashkent (Uzbekistan)	159
Kinshasha (Democratic Republic of Congo)	158
Kathmandu	154
Tehran (Iran)	145
Kolkata (India)	143
Mumbai (India)	126
Shanghai (China)	119
Belgrade (Serbia)	118
Baghdad (Iraq)	113
Sarajevo ( Bosnia hargegovina)	112
Note- AQI  level is different for each day, time, specific period, peak traffic hour, night hour, specific season, specific area, etc. The above data is an average or indicative only.

Air Quality Index (AQI) for the cleanest major cities in the world:
City	AQI level in the first week of November 2024.
Kyiv ( Ukraine)	6
San Francisco (USA)	7
Aukland (New Zealand)	10
Osaka (Japan)	11
Kyoto (Japan)	11
Kobe (Japan)	11
Tokyo (Japan)	11
Toronto (Canada)	12
Rome (Italy)	15
Sydney (Australia)	15
Vancouver (Canada)	16
Washington D.C. (USA)	18
Madrid (Spain)	19
Canberra (Australia)	20
Seattle (USA)	20
Astana (Kazakstan)	21
Montreal (Canada)	21
New York City (USA)	21
Portland (USA)	21
Kabul (Afghanistan)	22
Adis Ababa (Ethiopia)	22
Moscow (Russia)	22
Nairobi (Kenya)	22
Oslo (Norway)	23
Melbourne (Australia)	24
Salt Lake City (USA)	24
Helsinki (Finland)	25
Rotterdam (Netherlands)	27
Krakow (Poland)	28
Stockholm (Sweden)	28
Warsa (Poland)	28
Berlin (Germany)	28
London (UK)	29
Amsterdam (Netherlands)	34
Wroclaw (Poland)	36
Denver (USA)	36
Prague (Czech Republic)	37
Chicago (USA)	37
Birmingham (UK)	38
Lisbon (Portugal)	38
Doha (Katar)	39
Dakar (Senegal)	39
Kuala Lumpur (Malaysia)	39
Lyon (France)	40
Johannesburg (South Africa)	42
Detroit (USA)	49
Minneapolis (USA)	49
Munich (Germany)	51

Post Diwali (2024) AQI of the worst polluted cities, including suburbs of Delhi NCR in India:  The Diwali festival was celebrated in India on 31/10/2024. Due to the bursting of large-scale firecrackers and burning of paddy crop waste in Punjab, Haryana, and western UP state, the highest AQI level of 911 was recorded in Vaishali. Below is a list of some cities and suburbs of Delhi-NCR that have been worst hit by air pollution. The date and timing of the data recorded may vary. The below data are collected or provided by  https://www.aqi.in, and  https://www.livemint.com.
City	AQI
Vaishali (Ghaziabad, Delhi NCR)	911
Ghaziabad	893
Karkarduma (Delhi)	806
Noida -124	743
Nodia (sector-10)	673
Paschim Vihar (Delhi)	658
Shalimar Bagh (Delhi)	551
Lajpatnagar (Delhi)	593
Sonepat	567
Saket (Delhi)	528
Hauz Khas (Delhi)	481
Karnal	471
Gurugram (sector-51)	456
Gurgram (sector- 44)	439
Moradabad	421
Rampur	412
Sambhal	411
Pilibhit, Budaun, Bareilly, and Shahjahanpur	410
Gurgram (secor-108)	407
Faridabad	407
Ambala	405

Some of the Indian cities with the best AQI on 21 October 2024:
City/town	AQI
Madurai (Tamilnadu)	22
Chikkaballapur (Karnatka)	25
Ooty (Tamilnadu)	25
Madekeri (Karnataka)	28
Gadag (Karnataka)	28
Kalaburagi (Karnatka)	28
Palkalaiperur (Tamilnadu)	29
Thanjavur (Tamilnadu)	29
Nagaon (Assam)	30
Belgaum (Karnataka)	30
Udipi (Karnataka)	30

Factsheet about air pollution in the world:
As per the WHO report, 99% of the global population inhales polluted air.
Poor countries are suffering from the high exposure to highly polluted air.
Smoke inside houses and smog over the cities pose a great threat to our health and the earth’s climate.
Annually, nearly 7 million premature deaths are observed due to air pollution. Out of these 7 million premature deaths, roughly  4 million deaths are caused by outdoor (ambient) pollution.
Roughly 89% of premature deaths are found in poor countries of  Southeast Asia and the western Pacific regions.
It is a serious problem for children's health also.
Air pollution is the second highest risk factor for non-communicable diseases.
Household (indoor) air pollution contributes significantly to outdoor (ambient) pollution.
Data regarding household (Indoor) air pollution:
In the world, more than 2 Billion people (roughly one-third of the global population) are exposed to indoor (household) air pollution due to the use of open fires, kerosene-based inefficient stoves, biomass fuel ( wood, cow dung, crop waste, etc.), and coal. It is mostly used in poor countries, especially in rural areas. As per the estimate, in 2021, worldwide roughly 49% rural population and 14% urban population were using polluting fuels in houses. The region of Sub-Saharan Africa requires special attention because roughly 923 million people do not have access to clean fuel for household use as per one of the estimates in 2022.
As per the estimate, 3.2 million people (including 237000 children under 5 years old)  died worldwide in 2020 due to household pollution.  The majority of deaths belong to women living in poor countries, especially in rural areas. The composition of 3.2 million deaths may be subdivided based on different diseases caused by household air pollution. Such estimated data are given below:
Ischemic heart disease:	Roughly 1 million deaths (32% of 3.2 million).
Stroke:	Roughly 0.74 million deaths (23% of 3.2 million)
Lower Respiratory Infection (LRI):	Roughly 0.67 million deaths (21% of 3.2 million). Many children die due to pneumonia caused by LRI.
Chronic Obstructive Pulmonary Disease (COPD):	Roughly 0.6 million deaths (19% of 3.2 million)
Lung Cancer:	Roughly 0.2 million deaths (6% of 3.2 million)

Prevention of air pollution:
The Global Ecosystem, Earth's climate, and Air pollution are linked. Reducing air pollution will decrease various health problems, especially respiratory diseases, and help maintain a healthy Earth’s climate. Various options are available to prevent or reduce air pollution.
Most of the outdoor pollution is beyond the control of individuals.  It should be resolved or reduced by the policymakers of nations and regions, especially in related sectors like energy production, transport, waste management, agriculture, and urban planning.
Some of the ideas to reduce the air pollution in the related sectors are summarized below:
Industry management: Use of clean technology to reduce smoke emissions. Efficient management for urban and agricultural waste. Capturing of Methane gas emissions from waste sites instead of use as biogas (incineration).
Pollution-free or low-pollution transport system: It can be achieved by adopting and increasing: Clean modes of power generation. The network of rapid urban transit systems. The network of safe and separate paths for pedestrians and cyclists. We should encourage the same also. The interurban rail network for freight and passenger travel. The usage of low-emission vehicles and low-sulfur content fuel in the place of diesel or petrol-driven vehicles.
Energy-efficient urban infrastructure: Sustainable land use. Energy-efficient housing and construction, industries, power generation, etc. by planning green cities, energy-efficient buildings, etc.
Agricultural and solid waste management: We can do better by: Reducing the waste products. Segregating different types of waste. Recycling and reusing waste products. Adoption of improved, efficient, low-emission, easy, and affordable alternative methods of traditional waste management.
Health care management: By improving the technology and methodical procedures, we can reduce the waste and harmful radiation emitted by healthcare activities. Improved preventive measures are needed to neutralize the air pollution produced by such waste and radiation.
By increasing the usage of Non-conventional sources of energy: Instead of fossil-based energy, we should encourage the usage of alternative sources of energy like solar power, wind power, hydropower, etc. Household energy: Clean household energy for cooking, heating, and lighting should be affordable and easily available. Worldwide, more than 2 billion people are still using traditional solid and open-fire fuels like wood, cow dung, crop waste, coal, charcoal, kerosene, and inefficient stoves. To reduce household (indoor) pollution and protect health, the use of clean fuel and technologies needs to expand. Some clean fuel options are given below:
Solar energy	Electricity
Liquified Petroleum Gas (LPG)	Pipeline Natural Gas (PNG)
Alcohol-based fuel	Biogas stove with reduced emission.
Individual-level preventive measures to reduce air pollution:  We are using various means of lighting, cooking, heating, transport, and miscellaneous appliances that emit air pollution. Individually, we can reduce air pollution by the following steps:
Use public transport, carpool, and electric vehicles instead of a fossil-fuel-driven personal car as often as possible.
Proper maintenance of the personal car. Certainly, it will reduce air pollution.
Turn off the engine of the vehicle when the car is static.
Don't burn garbage, dry leaves, wood, coal, backyard fire, bonfire, or fossil fuels. Adopt alternative methods.
Don't cut trees; instead, plant new trees. Trees purify the air.
Limit the consumption of fossil fuel-based energy.

WHO (World Health Organization) plan to reduce the air pollution:
WHO has proposed the following interim targets to reduce the pollutant level of different components. The recommended AQG  level is also shown in the last row of each element:
PM2.5 (Diameter size is less than or equal to 2.5-micron): They are called fine particles. We can guess this size by comparing it with our hair diameter, which is around 100 micrometers (microns). It means 40 such fine particles may be accommodated on the tip of a hair.
Target	Pollution level in micrograms per cubic meter in annual averaging time:	Pollution level in micrograms per cubic meter in 24-hour averaging time:
1	35	75
2	25	50
3	15	37.5
4	10	25
Recommended  AQG level	5	15
As per WHO Air Quality Guidelines (AQG), to achieve the first target, if we reduce the PM2.5 concentration to the level of  35 micrograms per cubic meter in a year,  roughly 300000 global deaths may be averted annually.
PM10 (Diameter size is less than or equal to 10-micron):
Target	Pollution level in micrograms per cubic meter in annual averaging time:	Pollution level in micrograms per cubic meter in 24-hour averaging time:
1	70	150
2	50	100
3	30	75
4	20	50
Recommended AQG level	15	45
Ozone (O3):
Target	Pollution level in micrograms per cubic meter in peak season average time:	Pollution level in micrograms per cubic meter in 8 hours averaging time:
1	100	160
2	70	120
3	-	-
4	-	-
Recommended AQG level	60	100
Nitrozen Dioxide (NO2):
Target	Pollution level in micrograms per cubic meter in annual averaging time:	Pollution level in micrograms per cubic meter in 24-hour averaging time:
1	40	120
2	30	50
3	20	-
4	-	-
Recommended AQG level	10	25
Sulfur Dioxide (SO2):
Target	Pollution level in micrograms per cubic meter in annual averaging time:	Pollution level in micrograms per cubic meter in 24-hour averaging time:
1	-	125
2	-	50
3	-	-
4	-	-
Recommended  AQG level	-	40
Carbon Monooxide (CO):
Target	Pollution level in milligrams (mg) per cubic meter in annual averaging time:	Pollution level in milligrams (mg) per cubic meter in 24 hours averaging time:
1	-	7
2	-	-
3	-	-
4	-	-
Recommended AQG level	-	4 milligrams per cubic meter
Note: Some data may be more than 5 years old.

Air purifiers : Air purifiers help reduce air pollution and are very useful for indoor uses to maintain healthy air inside the houses/rooms.
Air purifiers for rooms: Their capacity is limited to a room. Some of the brands/models of  air purifiers for rooms are listed below:
Coway Airmega AP-1512HH Mighty: Price on Amazon: US$ 195 (white color) US$210 (black color) Price on Walmart: US$168 (white color) US$229 (black color)
Coway Airmega 100 Air Purifier: Price at Amazon: US$107 & US$130 (for different models) Price at Coway US$117 & US$130 (for different models)
Coway Airmega 200M: Price on Amazon: US$197(white color) US$229 (black color) Price on Walmart: US$197 (white color) US$ 197 (black color)
Coway Airmega 150: Price: US$190
Winix 4-Stage True HEPA Air Purifier: Price at Amazon: US $261
Winix 5500-2: Price on Amazon: US$155  Price on Walmart: US$200  Price on Wayfair: US$146
BLUEAIR Blue 411i Max Air Purifier: Price at Amazon: US$137 & US$170 (for different models) Price at Blueair: US$136 & US$170 (for different models)
Blueair Blue Pure 311i Max: Price on Amazon: US$183 Price on Home Depot: US$230
Blueair DustMagnet 5440i
Kenmore 850e Air Purifier: Price at Amazon: US$80
Levoit Core 300S Air Purifier: Price at Amazon: US$150
Levoit Vital 200S: Price on Amazon: US$190 Price on Best Buy: US$200
Blueair Blue Pure 211i Max: Price on Amazon: US$245 Price on Best Buy: US$245 Price on Home Depot: US$350
Briiv Air Filter: Price: US$373 at Briiv Price: US$360 at Goop
Blueair Blue Pure 511: Price on Amazon: US$100
Bissell Myair Pro Purifier: Price: US$173 at Amazon
Molekule Air Mini+: Price: US$ 350 approximately.
Clorox Smart Air Purifier: Prices for different models at Amazon: US$110 & US$120
Germ Guardian 4-in-1 Air Purifier: Price at Amazon: US$180
Austin Air HealthMate HM400: This air purifier is good for the filtration of Volatile Organic Compounds (VOC).
Hathaspace Smart True HEPA Air Purifier
Medify Air MA-10 Air Purifier: Price at Amazon: US$49
Air Purification for a large space or whole home: If we already have a centralized HVAC (Heating, Ventilation, and Air Conditioning) with MERV13  or higher grade filters in the home, we can supplement it by using the following air filters to clean the indoor air: Note: MERV 13 stands for Minimum Reporting Efficiency Value 13, which is standard to trap the pollutant particles.
Woosh smart air filter system	Lennox PureAir
PureAir S
Some other models for large spaces:
Molekule Air Pro Purifier: Price for different models: US$ 832 & US$1000 at Amazon US$ 1015 at Molekule
Levoit Core 400S Smart True HEPA Air Purifier: Price at Amazon: US$ 220
Levoit's Core 600S
Coway Airmega 250 Smart Air Purifier: Price: US$279 at Amazon & Coway (Price varies and is indicative only)
Coway Airmega 400S Smart Air Purifier: Price at Amazon: US$599
Medify MA-112: Suitable for public places to reduce cigarette smoke.
Honeywell HPA204 HEPA Air Purifier for Large Rooms: Price at Amazon: US$ 170 $ 220 (for different models)
Dyson Purifier Hot+Cool Air Purifier, Heater, and Fan: Prices for different models: US$700 & US$750 at Amazon US$750 at Dyson
Dyson Purifier Humidify+Cool Formaldehyde: Price: US$999 at Amazon (Price varies due to different modes and discounts on e-commerce platforms like Amazon, Wayfair, Dyson, etc.
Dyson Purifier Cool Purifying Fan: Discounted price at Amazon: US$450
Rabbit Air A3 Ultra Quiet Air Purifier: Price: US$750 at Amazon Price: US$770 at Rabbit Air

Final words:

The USA, Europe, and most of the developed countries do not face air pollution problems due to well-planned government policies, strict guidelines, literacy, awareness, available technology, resources, and financial capability.

Most of the poor, undeveloped, developing, densely populated countries are facing the air pollution problem due to a lack of well-planned government policies, strict guidelines, literacy, awareness, resources, financial capability, etc.

Air pollution poses serious health hazards to nature and humans.

The global population is suffering from various diseases, especially related to the Respiratory system, due to air pollution.

Millions of people die and suffer every year due to diseases caused by air pollution.

Long-term and well-planned government policies must be implemented to control outdoor (ambient) air pollution.

Individual and Government-level efforts are needed to control indoor pollution.

In case of need, air purifiers can be used to control air pollution.

Disclaimer: With the help of self-knowledge, following, and similar websites, the best efforts are made to provide you with updated and authentic information through this blog. However, the author does not take any responsibility (legal or otherwise) for its correctness and completeness. In case of any doubt, please contact us or cross-check from reliable sources. The prices of different models given in the blog are subject to change frequently. The author of the blog is not responsible for any difference in the actual price as of the date. This blog is not AI-generated and is typed manually, therefore, any typographical error is regretted. https://www.google.com https://www.who.int https://www.metropolisindia.com https://www.iqair.com https://www.condorchem.com https://www.pca.state.mn.us https://www.sciencedirect.com https://www.livemint.com https://www.thehindu.com https://www.nytimes.com https://www.bhg.com https://www.architecturaldigest.com https://www.airnow.gov https://www.epa.gov https://www.lung.org https://indianexpress.com

Take precautions and remain healthy. ==The End==