Incense has been used for thousands of years in religious rituals, spiritual practices, and to create a pleasant aroma. Since this practice involves combustion, which generates smoke, questions have been raised about the potential health impact of inhalation. Understanding the smoke’s composition is key to determining the risks.
Understanding Particulate Matter and Gases
Incense smoke is a complex mixture of gases and fine solid particles released through incomplete combustion. The most concerning component is Particulate Matter (PM), specifically the ultrafine fraction known as PM2.5 (2.5 micrometers or less). These particles bypass the body’s natural defenses, penetrating deep into the lungs and potentially entering the bloodstream.
Studies show that burning incense generates extremely high concentrations of PM2.5 indoors, sometimes exceeding levels produced by burning tobacco. Concentrations are significantly higher inside homes and places of worship where incense is regularly used.
The smoke also releases hazardous gases, including Carbon Monoxide (CO), nitrogen oxides, and sulfur oxides. The combustion process yields Volatile Organic Compounds (VOCs) and Polycyclic Aromatic Hydrocarbons (PAHs). Specific VOCs identified include formaldehyde, benzene, and toluene. Formaldehyde and benzene are concerning due to their toxicity and potential to accumulate indoors, often surpassing air quality guidelines.
Respiratory and Systemic Health Consequences
Inhalation of incense smoke, with its high concentration of ultrafine particulate matter and toxic gases, primarily affects the respiratory system. Exposure causes acute airway irritation, leading to symptoms like coughing, wheezing, and rhinitis. For individuals with pre-existing conditions such as asthma or Chronic Obstructive Pulmonary Disease (COPD), regular incense use can exacerbate symptoms and trigger attacks.
PM2.5 particles deposit in the deepest parts of the lungs, inducing oxidative stress and inflammation. This damage can disrupt the lung’s protective barrier function and impair tissue growth, especially in children. Household incense burning has been linked to impaired lung function and a higher risk of respiratory infections, including bronchitis and pneumonia.
The inflammatory response can also have systemic effects. Prolonged exposure has been linked to cardiovascular stress, potentially impairing the function of the endothelium lining the blood vessels. Systemic inflammation is indicated by increased levels of inflammatory markers such as C-reactive protein (CRP) and tumor necrosis factor-alpha (TNF-α). High exposure has also been investigated as a risk factor for certain cancers, with some studies noting an increased lung cancer risk when combined with tobacco smoking.
Risk Differences Based on Incense Type
The health risk profile is influenced by the raw materials used. Natural incense is typically composed of pure plant materials like herbs, resins, essential oils, and aromatic woods such as sandalwood or agarwood. While combustion of these natural components still generates particulate matter, the smoke’s chemical complexity is generally lower than synthetic varieties.
Synthetic or lower-quality incense often relies on chemical fragrances, artificial dyes, and charcoal cores. When burned, these synthetic ingredients contribute a greater and more varied load of Volatile Organic Compounds (VOCs) to the air. Using charcoal as a base material also increases the emission of carbon monoxide and other combustion byproducts. Although all incense produces harmful PM2.5, synthetic products introduce a higher concentration of chemical irritants and complex VOCs.
Minimizing Inhalation Risks
Individuals who continue burning incense can take several steps to reduce inhalation risk. The most effective strategy is robust ventilation during and after burning. Opening a window and creating a cross-breeze helps rapidly dilute and remove concentrated smoke particles. Burning incense in poorly ventilated or confined spaces should be avoided entirely to prevent pollutant accumulation.
Limiting the duration and frequency of use restricts overall exposure. Positioning the burner away from immediate breathing zones, such as across the room, allows the smoke to disperse. For sensitive individuals, switching to smokeless alternatives, like essential oil diffusers, provides a similar aromatic experience without combustion byproducts. A high-efficiency air purifier can also continuously filter out residual airborne particulate matter.