Why do VOC gases affect indoor air quality?

When we talk about air pollution, most people think of smog, car exhaust or industrial emissions. However, scientific research shows that indoor air pollution is often 2-5 times more serious than outdoor air pollution (EPA, 2023), and one of the main invisible threats is volatile organic compounds (VOCs). These chemicals not only affect air quality, but are also associated with headaches, allergies, and even cancer. So, what exactly are VOCs? How do they affect our health? And how can we reduce their harm?
The Nature of VOCs: From Chemical Molecules to Health Threats
What are VOCs?
Volatile Organic Compounds (VOCs) refer to organic chemicals that easily evaporate into gases at room temperature. They have low boiling points (usually between 50-260°C), which means they can easily change from liquid or solid state to gas and mix into the air we breathe.
According to the definition of the World Health Organization (WHO, 2022), VOCs include hundreds of different compounds, the most common of which are:
Benzene (from paint, car exhaust) - Class 1 ammonia, formaldehyde (from plywood, furniture) - can induce leukemia, toluene, xylene (solvents, cleaning agents) - damage the nervous system, acetaldehyde (cigarettes, combustion products) - related to respiratory diseases
Where do VOCs come from?
VOCs are almost everywhere, and the main sources include: building materials (paint, glue, composite wood), household items (cleaners, air fresheners, cosmetics), office equipment (printer ink, copiers), human activities (smoking, cooking).
How do VOCs affect indoor air quality?
Short-term effects: From headaches to allergies, low-concentration VOCs exposure may cause: irritation of the eyes, nose, and throat (especially formaldehyde), headaches, dizziness, fatigue (toluene affects the nervous system), aggravated allergic reactions (such as asthma patients are more sensitive to VOCs), and a 2024 study in the journal Indoor Air pointed out that for every 10μg/m³ increase in VOCs concentration, the risk of asthma attacks in children increases by 3%.
Long-term hazards: cancer and chronic diseases, some VOCs (such as benzene and formaldehyde) have been listed as clear carcinogens by the World Health Organization (WHO) and the International Agency for Research on Cancer (IARC). Long-term exposure may lead to: leukemia, liver and kidney damage A global study in The Lancet Planetary Health in 2023 estimated that indoor VOCs exposure causes about 400,000 premature deaths each year, mainly from lung cancer and cardiovascular disease.
VOC's "synergistic effect": more dangerous than alone
VOCs rarely exist alone, they react chemically with other pollutants (such as ozone, PM2.5) to form more dangerous secondary pollutants.
Formaldehyde + ozone → free radicals (increases respiratory inflammation)
Benzene + ultraviolet light → photochemical smog (similar to urban haze)
How to reduce VOC exposure? Scientifically verified methods:
Source control: choose low-VOC products, use water-based paint (90% lower VOC than oil-based paint); ventilation and air purification; open windows for ventilation (1 air change per hour can reduce VOCs by 50%); use activated carbon filters (effective for benzene and formaldehyde); photocatalytic oxidation (PCO) technology (latest research shows that it can decompose VOCs); use VOC catalysts: The core logic of VOC catalysts is: through the cycle of adsorption-activation-reaction-desorption, VOCs are efficiently oxidized into harmless products at low temperatures. Compared with direct combustion (high temperature and high energy consumption), it is more energy-efficient and avoids secondary pollution (such as dioxins) caused by incomplete combustion. Therefore, it is widely used in VOCs treatment scenarios such as industrial waste gas and automobile exhaust.
Through scientific cognition and action, we can greatly reduce the risk of exposure. It is recommended to test indoor air quality every 2 years, especially for newly renovated homes. After all, breathing health is the real "invisible wealth".

author: Hazel
date:2025-07-23