Combating air pollution requires a decisive shift away from fossil fuels, alongside measures such as controlled fertilizer use in agriculture, prevention of stubble burning, monitoring environmental policies and raising public awareness, according to professor Gülen Güllü, head of the Department of Environmental Sciences at Hacettepe University’s Faculty of Engineering.
The United Nations designated Sept. 7 as “International Clean Air Day for Blue Skies” in 2019, aiming to encourage global initiatives to improve air quality and raise public awareness. The theme for this year is “Race for Air.”
Professor Güllü explained that air pollution occurs when gases, particulate matter, or liquid compounds in the atmosphere reach levels that affect human and environmental health. She highlighted that many atmospheric molecules can be measured, and when certain concentrations are reached, they indicate whether the air is clean or polluted.
Particulate matter, often referred to as PM, is classified by particle size into PM2.5 (particles smaller than 2.5 microns) and PM10. The tiniest particles can penetrate deep into the lungs, enter the circulatory system and trigger vascular problems.
“We can detect particles ranging from 30 to 100 microns in the air, but 10 microns is the level we actually breathe. The cilia in our noses and the mucus in our respiratory system allow particles smaller than 10 microns to enter the body. That is why we focus on PM10 rather than total particle concentration,” she explained.
Güllü noted that gaseous pollutants such as sulfur dioxide, nitrogen dioxide, carbon monoxide and ozone threaten human health. Ozone, in particular, can worsen asthma and damage plant leaves, causing agricultural losses.
While natural factors such as wildfires and dust clouds contribute to air pollution, human activities account for the majority of the problem. Thermal power plants, fossil fuel combustion, cement and petrochemical plants, mining operations, transportation, improper agricultural practices, ineffective waste management, and construction work are among the main human-induced sources of pollution.
Air pollution is the second leading cause of death worldwide, according to the World Health Organization (WHO). Indoor air pollution from biomass burning also poses serious risks. WHO reports that 99% of the world’s population breathes air above recommended guidelines, resulting in millions of premature deaths every year.
The dirtiest air is found in countries with inefficient heating systems, including India, Pakistan and Bangladesh, where cities such as Delhi, Lahore and Dhaka record pollutant levels far above WHO limits. In contrast, Northern European countries benefit from humid climates and soil-covered vegetation, which help reduce pollution. South Asian nations face harsher conditions due to dry and dusty climates.
High humidity, Güllü explained, can accelerate particulate formation and block sunlight at ground level, worsening air quality. Africa also struggles with pollution due to rapid urbanization, low-quality fuels and uncontrolled industry. Europe has made significant progress by reducing emissions and relocating heavily polluting industries, though cities like London and Paris still face traffic-related pollution risks.
She emphasized that combating air pollution requires abandoning fossil fuels while also enforcing policies on controlled fertilizer use, stubble burning prevention, and public education. Elderly individuals with pre-existing illnesses, as well as infants and children, are the most vulnerable populations.
The 2024 World Air Quality Report by IQAir, covering 8,954 cities across 138 countries, reveals the global extent of air pollution. Chad records the highest PM2.5 concentrations, followed by Bangladesh, Pakistan, the Democratic Republic of Congo and India. Türkiye ranks 67th, with a PM2.5 level of 15.3 micrograms per cubic meter.
The World Meteorological Organization (WMO) reports that from 2003 to 2024, biomass burning caused PM2.5 increases in northern Canada, the Amazon, Siberia, and Central Africa. Northern India experienced rising PM2.5 levels from human activities and biomass burning, while Saharan dust transported across northwest Africa contributed to additional pollution. Eastern China saw declines in PM2.5 due to reduced human emissions, and northeast Africa also recorded decreases linked to lower dust emissions.
Professor Güllü concluded that tackling air pollution demands both structural policy interventions and individual awareness, with fossil fuel reduction at the forefront of global and national efforts.
