# PM 2.5 concentration indoors from indoor sources in Finland

## Scope

This variable describes the indoor air PM 2.5 concentration in Finland originating from indoor sources, such as environmental tobacco smoke (ETS), cooking and wood stove combustion.

## Definition

### Data

```Description of the data used for obtaining the value of the variable
(e.g. measurement data; mathematical method and its parameters).
Please include references (preferably using the <ref></ref> tags)
and links to original data, as appropriate.
```

### Causality

Model [1]

Cindoor sources = (NcigScig)/(a+k)Vt + (Scooktcook)/(a+k)Vt + (Swood stovetwood stove)/(a+k)Vt + (Scombustiontcombustion)/(a+k)Vt

• Cindoor sources = PM2.5 concentration in indoors from indoor sources (µg/m3)
• Ncig = number of cigarettes smoked in the time t
• Scig = a source strength for cigarettes (µg particles per cigarette)
• V = volume of the room (m3)
• a = aeration (h-1)
• t = time (h)
• K = average deposition (h-1)
• Scook = a source strength for cooking (µg/h)
• tcook = time of cooking activities (h)
• Swood stove = a source strength factor for wood stove (µg/h)
• twood stove = time of wood stove use (h)
• Scombustion = a source strength factor for other combustion sources (e.g. natural gas, fuel oil) (µg/h)
• tcombustion = Time of heating with other combustion sources (h)

µg/m3

### Formula

```Algebra or other explicit methods if possible
(e.g. Analytica code between the <anacode></anacode> delimiters).
```

## Result

```If possible, a numerical expression or distribution.
```