The lung-deposited surface area (LDSA) concentration of particles in the air describes the surface area of the particulate matter that settles in the deepest parts of the lungs, i.e. the alveoli. The results are available as a graph or table. The unit is µm2/cm3. The monitoring results are displayed hourly. In the graph, you can select the monitoring locations whose results you want to view. You can select a day, week, or month as the reference period. The monitoring results are unverified hourly averages.
In the Helsinki metropolitan area, the LDSA concentrations of particles in the air are particularly affected by traffic exhaust gases, smoke from wood burning, and long-range transport of air pollutants. The annual averages are approximately 20 µm2/cm3 in very busy environments, 11–12 µm2/cm3 in densely built detached house areas, and 8 µm2/cm3 in rural settings. There is no guideline or limit value for the LDSA concentration, but an indicative air quality index has been developed for the graphic display of high concentrations.