Stofmassa

Stofmassa is the mass of particulate matter (PM) present in a given volume of air or another medium. It is usually expressed as micrograms per cubic meter (µg/m³) and is a key parameter in environmental and health risk assessments. The term is most commonly used in air quality monitoring, where it helps evaluate concentrations of fine particles that can penetrate deep into the respiratory system.

Because particulate matter can carry adsorbed pollutants such as heavy metals, polycyclic aromatic hydrocarbons, and allergens, its mass concentration has direct implications for human health. Long‑term exposure to elevated PM levels has been linked to cardiovascular disease, lung cancer, and premature mortality. In addition, particulate matter influences climate by scattering and absorbing solar radiation and acting as cloud condensation nuclei, thereby affecting the Earth’s radiative balance.

Stofmassa is determined using gravimetric sampling, where filters capture particles over a fixed period and the mass difference between pre‑ and post‑sampling weights is calculated. Modern methods also employ optical particle counters or aethalometers, which infer mass from light scattering properties. Calibration against gravimetric standards is necessary for accurate results. Other techniques include chemical analysis for specific constituents that contribute to the total mass.

Regulatory frameworks set limits on acceptable stoffmassa levels. The World Health Organization recommends a maximum 24‑hour mean of 25 µg/m³ for PM₂.₅ and 40 µg/m³ for PM₁₀, though national guidelines can be more stringent. Industrial emissions, vehicular exhaust, construction activities and natural sources such as dust storms contribute to particulate matter. Strategies to reduce stoffmassa include emission controls, improved combustion technology, and the use of barriers or wet suppression systems at sources.