Air Pollution: Which City Suffers The Most?

Air pollution is a critical threat to both human health and environmental stability. According to the World Health Organization (WHO), 99% of the world's population lives in areas that do not meet the recommended air quality guidelines. In 2021, approximately 8.1 million deaths worldwide could be attributed to air pollution. A recent report by IQAir, a Swiss company that tracks global air quality, revealed that the cities with the worst air pollution in the world are mostly located in Asia, with India and Pakistan being home to some of the most polluted cities.

N'Djamena, Chad ranked as the most polluted city in 2024

According to a report by IQAir, a Swiss company that monitors global air quality, N'Djamena in Chad was ranked as the world's most polluted city in 2024. The report specifically examined fine particulate matter, or PM2.5, which is one of the smallest yet most harmful pollutants. These particles, which are 1/20th the width of a human hair, can bypass the body's natural defences and enter the lungs or bloodstream, causing irritation and inflammation. They have been linked to respiratory issues, chronic kidney disease, cancer, stroke, heart attacks, and a higher risk of depression and anxiety.

N'Djamena's ranking as the most polluted city is notable, as the list of the world's top 20 most polluted cities primarily consists of Asian cities. China, which previously dominated global rankings, has shown slight improvement, with air quality enhancing in megacities like Beijing, Shanghai, and Guangzhou. However, concerns have been raised about the Chinese power industry's plans to build new coal plant capacity.

The United States, particularly North America, has also made strides in reducing PM2.5 levels, with an annual average drop of 22% from 2023. Despite this, cities in California, such as Ontario, Bloomington, and Huntington Park, were ranked among the most polluted in North America.

While the specific data for N'Djamena's air pollution in Chad is not readily available, the US Embassy in the city provides a real-time air quality index. This data can be accessed programmatically through an API, allowing for ongoing monitoring of the air quality in this highly polluted area.

Air pollution poses a severe health threat, impacting vulnerable populations such as children, older adults, and individuals with lung diseases. It can trigger asthma attacks, impair lung development in children, and even lead to fatal consequences. Therefore, addressing air pollution and implementing measures to improve air quality are crucial to safeguard public health and mitigate the adverse effects on vulnerable populations.

India is home to some of the world's most polluted cities

The main sources of pollution in India include industry, vehicles, crop burning, and domestic cooking. In urban areas, pollution primarily originates from industrial activities and vehicles, while in rural regions, the burning of organic material is a significant contributor. The fuel used for domestic stoves, typically a mixture of wood, dried leaves, hay, and dried animal dung, produces smoke and pollutants five times higher than coal. Additionally, 24% of city pollutants come from auto-rickshaws and taxis running on adulterated fuel, which is a common practice in South Asia.

To address the air pollution crisis, the Indian government introduced the National Clean Air Program (NCAP) in 2019, aiming to reduce pollution levels by 20-30% by 2024 in over 122 severely affected cities. The government of New Delhi implemented the "odd/even" rule in 2017 to restrict car usage in the city centre based on registration plate numbers. India also set goals to introduce over 1,000 electrically powered buses and upgrade engines using fossil fuels to meet stringent BS6 standards. By 2023, the country aims to have 25% of privately owned vehicles as electric and all power plants using renewable energy.

Despite these efforts, India continues to face significant challenges in reducing air pollution. The taxation system, with higher taxes on gasoline than diesel, and cultural traditions that favour specific fuel types, contribute to the complex nature of the problem. Additionally, the improvement in air quality in some Indian cities has been slow, as seen in the case of New Delhi, which continues to struggle with severe air pollution.

China has improved air quality in cities like Beijing and Shanghai

China, which once dominated the rankings for the world's worst air pollution, has seen an improvement in recent years. Notably, cities like Beijing and Shanghai, which were once shrouded in smog, have taken significant steps to enhance their air quality.

Beijing, the capital city of China, has been at the forefront of the country's battle against air pollution. With a population of over 21 million, Beijing has implemented various measures to curb vehicle emissions and promote electric mobility. The city has introduced stricter emissions standards, enforced limits on the number of vehicles entering the city, and improved its public transportation system. Beijing has also focused on reducing the use of coal-fired boilers and providing cleaner fuels for households. As a result, the city has seen a notable decrease in nitrogen dioxide and PM10 concentrations, although ozone pollution remains a concern.

Shanghai, the largest city in China, has also made strides in improving its air quality. In addition to embracing electric buses and vehicles, Shanghai has been a leader in the expansion of solar and wind power. The city has played a crucial role in China's campaign against air pollution, particularly targeting the cities that fueled its economic growth.

According to a report, the national annual average PM2.5 concentration in China decreased from 32.5 micrograms per cubic meter to 31. This improvement was observed in megacities like Beijing, Shanghai, Chengdu, Guangzhou, and Shenzhen. Despite these improvements, China still faces challenges, as it is the world's largest carbon dioxide emitter, and there are concerns about plans to expand coal plant capacity.

While China has made progress in improving air quality in cities like Beijing and Shanghai, it remains a work in progress. The country continues to combat air pollution on a national level, with the government investing heavily in pollution reduction initiatives. China's efforts to improve air quality have had a significant impact on the lives of its citizens, and the country remains committed to long-term solutions for cleaner air.

The worst air pollution in North America was in California

According to a report by IQAir, a Swiss company that monitors global air quality, the cities with the worst air pollution in North America were in California. The cities specifically named were Ontario, Bloomington, and Huntington Park—all in California. The report looked specifically at fine particulate matter, or PM2.5, which is one of the smallest yet most dangerous pollutants. PM2.5 is released from the combustion of fossil fuels, dust storms, and wildfires, and it can be inhaled past the body's natural defenses, causing irritation and inflammation. Exposure to PM2.5 has been linked to respiratory problems, kidney disease, cancer, stroke, and heart attacks, as well as a higher risk of depression and anxiety.

California's air quality is significantly impacted by wildfires, which can cause severe spikes in pollution levels, even though they are temporary. The state's most populous cities, including Los Angeles, San Diego, San Jose, and San Francisco, are all located near coastal mountain ranges, making them more susceptible to the effects of wildfires. Human-driven climate change is expected to worsen California's air quality by intensifying wildfires in the future.

While the United States has seen an overall reduction in PM2.5 levels, with a 22% decrease in the annual average from 2023, California continues to struggle with poor air quality. According to the American Lung Association's "State of the Air 2019" report, California leads the country in cities with the worst air pollution. Bakersfield, Fresno-Madera-Hanford, Visalia, Los Angeles-Long Beach, and San Jose-San Francisco-Oakland are among the top five cities with the highest annual PM2.5 levels. These cities also rank high in ozone pollution, with Los Angeles-Long Beach, Visalia, Bakersfield, Fresno-Madera-Hanford, and Sacramento-Roseville being the top five.

California's air pollution has multiple sources, including vehicular emissions, energy production from fossil fuels, household energy consumption, and wildfires. Areas with dense populations, such as those near the Coastal mountains, often experience higher pollution levels due to increased traffic, industrial activity, and domestic emissions. Despite California's reputation for clean energy initiatives, the state continues to face challenges in improving its air quality, especially with the growing threat of climate change-induced wildfires.

The cleanest metropolitan area in the world is Mayaguez, Puerto Rico

While air pollution is a serious issue in many cities around the world, Mayagüez, Puerto Rico stands out as an exceptional example of clean air quality. In fact, it can be boldly stated that Mayagüez is the cleanest metropolitan area in the world. This is a remarkable achievement and a testament to the efforts of the local government and community in prioritizing the environment and the health of its residents.

The clean air in Mayagüez is a result of a combination of factors, including its geographical location, favourable weather conditions, and proactive measures taken by the local authorities and community to protect and preserve the quality of the air. The city benefits from its coastal location, with sea breezes helping to disperse pollutants and provide a constant supply of fresh air. Additionally, the local government has implemented a range of initiatives to reduce pollution, including investing in renewable energy sources and promoting sustainable modes of transportation.

The residents of Mayagüez are also actively involved in maintaining the clean air they cherish. Community organizations, such as the American Lung Association, play a vital role in advocating for clean air and educating the public about the health impacts of air pollution. They work closely with local authorities to ensure that air quality standards are not only met but exceeded, and their efforts have resulted in tangible improvements in the lives of those who call Mayagüez home. It is this combination of collective action and individual responsibility that has led to Mayagüez's success in becoming the cleanest city in the world.

In contrast, many other cities around the world continue to struggle with poor air quality, with Asia dominating the list of the most polluted places. According to a report by IQAir, a Swiss company that tracks global air quality, the top 20 most polluted cities in 2024 were mostly located in Asia, with N'Djamena in Chad being ranked as the most polluted city. China, which once led the rankings, has shown small improvements, with cities like Beijing, Shanghai, and Guangzhou making progress in improving their air quality. However, it is important to note that these improvements are fragile, and continued efforts are necessary to ensure that air pollution levels do not worsen again.

The United States, and specifically California, has also faced challenges with air pollution. Ontario, Bloomington, and Huntington Park were ranked as the most polluted cities in North America, all located within California. However, the country has made significant strides, with a 22% reduction in PM2.5 levels across the United States from 2023 to the following year. This improvement can be attributed to the Clean Air Act, which has driven pollution reduction for over 50 years, and the work of the Environmental Protection Agency (EPA) in monitoring and enforcing air quality standards.

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