Most air pollution originates from human activities

Prof. Dr. Gülen Güllü, a faculty member at Hacettepe University, emphasized that the most important step in fighting air pollution is abandoning fossil fuels. She also stressed the importance of controlled fertilizer use in agriculture, preventing stubble burning, monitoring implemented policies, and raising public awareness.

The United Nations (UN) established September 7 as the "International Clean Air Day for Blue Skies" in 2019 to promote efforts to improve air quality and raise public awareness. This year's theme is "Race for Air."

Prof. Güllü, Head of Environmental Sciences at Hacettepe University's Faculty of Engineering, explained that air pollution occurs when gases, particles, or liquid compounds reach levels harmful to human and environmental health.

Many airborne molecules can be measured, and when they reach certain levels, air is classified as clean or polluted. She noted that particulate matter is categorized by size into PM2.5 and PM10, with particles smaller than 2.5 microns called PM2.5 and those smaller than 10 microns called PM10.

She explained that fine particles can penetrate deep into the lungs and enter the circulatory system, causing vascular diseases. Although particles ranging from 30 to 100 microns can be seen in the air, only those smaller than 10 microns are inhalable. The tiny hairs and mucus in our noses allow particles smaller than 10 microns to enter our bodies, so PM10 levels are key for health assessments.

Güllü emphasized that gaseous pollutants such as sulfur dioxide, nitrogen dioxide, carbon monoxide, and ozone pose serious health risks. Ozone can cause asthma and damage plant leaves, leading to agricultural losses.

While natural sources like forest fires and dust clouds contribute to pollution, most air pollution is human-caused, including emissions from thermal power plants, fossil fuel burning, cement and petrochemical plants, mining, transportation, improper agricultural practices, waste mismanagement, and construction activities.

According to the World Health Organization (WHO), air pollution ranks as the second leading cause of death globally, resulting in 8.1 million premature deaths annually. Indoor pollution from biomass burning is especially problematic. WHO states that 99% of the global population breathes air that exceeds its pollution guidelines.

Prof. Güllü pointed out that the worst air quality is in countries like India, Pakistan, and Bangladesh due to poor heating systems. Cities such as Delhi, Lahore, and Dhaka experience pollution levels many times above WHO limits.

She also highlighted that northern European countries benefit from humid, vegetated ecosystems that help improve air quality, whereas dry and dusty climates in South Asia worsen pollution.

Weather conditions also affect pollution levels. For example, high humidity in China promotes particulate formation and reduces sunlight penetration, worsening air quality despite strict controls. Africa faces severe pollution due to rapid urbanization, low-quality fuel use, and unregulated industry. Europe has made significant progress in reducing emissions, relocating polluting industries away from populated areas, but traffic-heavy cities like London and Paris still face risks.

Prof. Güllü stressed the urgent need to combat air pollution, naming the transition away from fossil fuels as the most crucial step. Controlled fertilizer use, preventing stubble burning, monitoring policies, and raising public awareness are also vital. She noted that elderly people with existing illnesses, babies, and children are the most vulnerable groups.

The 2024 World Air Quality Report by IQAir, analyzing PM2.5 data from 8,954 cities in 138 countries, revealed Chad as having the highest PM2.5 concentration at 91.8 micrograms per cubic meter, followed by Bangladesh (78), Pakistan (73.7), Democratic Republic of Congo (58.2), and India (50.6). Turkey ranked 67th with 15.3 micrograms.

The World Meteorological Organization (WMO) noted increases in PM2.5 levels in northern Canada, the Amazon, Siberia, and Central Africa in 2024, linked to biomass burning. Elevated PM2.5 was also observed in northern India due to human-caused pollution and biomass burning. Dust from the Sahara Desert increased PM2.5 over parts of northwest Africa and the Atlantic Ocean. Meanwhile, eastern China saw decreases in PM2.5 due to reduced emissions, and dust emissions declined in northeast Africa.