Outdoor air pollution (ozone, smog, sulfur dioxide, nitrogen dioxide, petroleum combustion products) can damage the respiratory lining and cilia and impair mucociliary clearance. Air pollution can also increase nasal congestion and affect immune responses in the nasal, sinus and lung tissues. Air pollutants can cause flares of asthma and nasal/sinus disease as well as worsening of other chronic lung conditions. These factors can also increase the chances of contracting a respiratory infection which could lead to sinusitis.
Indoor pollution is more of a respiratory concern than outdoor pollution since 90% of adult time is spent indoors. Indoor pollutants (dust, mold, insect products, pesticides, electronic devices, construction dust and debris, combustion emission, volatile organic compounds, poor ventilation, secondhand tobacco smoke) can affect normal mucociliary clearance, membrane damage and immune responses.