Which environmental factor significantly contributes to asthma in urban areas?

Air pollution is a significant contributor to asthma in urban areas due to its direct effects on respiratory health. Urban environments often have higher levels of pollutants, such as particulate matter, nitrogen dioxide, and sulfur dioxide, resulting from vehicle emissions, industrial discharges, and other human activities. Exposure to these pollutants can irritate the airways and trigger asthma symptoms, making it harder for individuals with asthma to breathe and increasing the frequency and severity of asthma attacks.

In addition to its immediate health impacts, air pollution can also exacerbate existing respiratory conditions, leading to increased hospital visits and medical costs. Children, the elderly, and individuals living with pre-existing respiratory issues are often more vulnerable to the harmful effects of air pollution. Addressing air quality through public policy, urban planning, and community health initiatives is crucial in mitigating asthma and improving overall public health in urban settings.

Other factors listed may have indirect connections to asthma risk, but air pollution stands out as the direct environmental factor significantly affecting lung health and asthma prevalence in urban populations.