Exercising in polluted urban environments raises the volume of air—and with it, airborne pollutants—delivered to the lungs. During moderate to intense activity ventilation rates increase, so more fine particulate matter and gaseous pollutants reach the distal airways and alveoli. Evidence synthesized by Robert D. Brook, University of Michigan, and colleagues highlights how this elevated intake amplifies local airway irritation and can translate into systemic cardiovascular stress through inflammatory and oxidative pathways.
Mechanisms and immediate effects
Higher inhaled doses of PM2.5, nitrogen oxides, and ozone during exercise promote airway inflammation, bronchial hyperreactivity, and transient reductions in lung function, which may provoke cough, wheeze, or breathlessness—particularly in people with asthma. N. L. Mills, University of Edinburgh, has described how particulate components can trigger endothelial dysfunction, increase blood coagulability, and provoke autonomic shifts that raise short-term risks for arrhythmia and ischemic events. These responses are dose- and susceptibility-dependent: healthy young adults tolerate exposures differently from older people or those with chronic cardiopulmonary disease.
Long-term consequences and social context
Repeated exposures over months to years can contribute to accelerated atherosclerosis, chronic obstructive pulmonary disease progression, and greater cardiovascular morbidity. Mark Nieuwenhuijsen, Barcelona Institute for Global Health, has examined the balance between the health benefits of active travel and the risks of traffic-related air pollution, finding that net benefits often favor activity, but that context—pollution level, route, and individual vulnerability—matters. Populations living near busy roads, often lower-income or marginalized communities, experience higher cumulative exposure, creating a territorial and environmental justice dimension to risk.
Practical implications follow from these physiological effects: where pollution is high, shifting exercise to low-traffic routes or times of day, using indoor spaces with adequate filtration, and following local air quality alerts can reduce exposure without abandoning physical activity. Public health responses that combine emission reduction, urban planning for green corridors, and targeted protection for vulnerable communities address both immediate physiological risks and the broader social determinants that shape who bears them.