PM is a widespread air pollutant, consisting of a mixture of solid and liquid particles
suspended in the air.
Commonly used indicators describing PM that are relevant to health refer to the mass
concentration of particles with a diameter of less than 10 µm (PM10) and of particles with
a diameter of less than 2.5 µm (PM2.5). PM2.5, often called fine PM, also comprises ultrafine
particles having a diameter of less than 0.1 µm. In most locations in Europe, PM2.5 constitutes
50–70% of PM10.
PM between 0.1 µm and 1 µm in diameter can remain in the atmosphere for days or weeks
and thus be subject to long-range transboundary transport in the air.
PM is a mixture with physical and chemical characteristics varying by location. Common
chemical constituents of PM include sulfates, nitrates, ammonium, other inorganic ions such
as ions of sodium, potassium, calcium, magnesium and chloride, organic and elemental
carbon, crustal material, particle-bound water, metals (including cadmium, copper, nickel,
vanadium and zinc) and polycyclic aromatic hydrocarbons (PAH). In addition, biological
components such as allergens and microbial compounds are found in PM. If you care about health deal, do not miss

PM10 and PM2.5 include inhalable particles that are small enough to penetrate the thoracic
region of the respiratory system. The health effects of inhalable PM are well documented.
They are due to exposure over both the short term (hours, days) and long term (months,
years) and include:
• respiratory and cardiovascular morbidity, such as aggravation of asthma, respiratory
symptoms and an increase in hospital admissions;
• mortality from cardiovascular and respiratory diseases and from lung cancer.
There is good evidence of the effects of short-term exposure to PM10 on respiratory health,
but for mortality, and especially as a consequence of long-term exposure, PM2.5 is a stronger
risk factor than the coarse part of PM10 (particles in the 2.5–10 µm range). All-cause daily
mortality is estimated to increase by 0.2–0.6% per 10 µg/m3 of PM10 (6,7). Long-term
exposure to PM2.5 is associated with an increase in the long-term risk of cardiopulmonary
mortality by 6–13% per 10 µg/m3 of PM2.5 (8–10).