Air quality refers to the condition of the air within our environment, especially as it relates to the presence of pollutants that can affect human health, ecosystems, and climate. The assessment of air quality typically involves measuring the concentration of key pollutants such as particulate matter (PM2.5, PM10), nitrogen oxides (NOx), sulfur dioxide (SO2), ozone (O3), and volatile organic compounds (VOCs). These pollutants stem from both anthropogenic activities (e.g., fossil fuel combustion, industrial processes, and agriculture) and natural sources (e.g., wildfires, dust storms, and volcanic activity).
In urban areas, high levels of pollutants are closely associated with traffic emissions and industrial outputs, while rural regions may experience air quality degradation from agricultural activities or cross-border pollution transport. Poor air quality is a leading risk factor for respiratory and cardiovascular diseases, exacerbating conditions such as asthma, bronchitis, and heart disease. It is also linked to broader environmental issues such as acid rain, eutrophication, and biodiversity loss.
To monitor and manage air quality, several international standards and guidelines have been established, including those from the World Health Organization (WHO) and the European Union (EU). These guidelines set threshold levels for various pollutants to mitigate their harmful effects on both human health and ecosystems.
In the context of climate change, there is a complex relationship between air quality and climate forcing. Certain air pollutants, such as black carbon (a component of PM), have both local health impacts and global climate effects due to their ability to absorb sunlight and warm the atmosphere. Conversely, air quality regulations, which aim to reduce emissions, can contribute to climate mitigation by lowering greenhouse gas precursors like methane and ozone.
Addressing air quality requires a multidisciplinary approach, involving atmospheric science, public health, engineering, and policy interventions. Integrated assessment models (IAMs) are increasingly used to explore the co-benefits of air quality and climate policies, allowing policymakers to design strategies that reduce pollution while achieving climate goals.