# Calculating dust concentration

How can I determine the concentration of dust? Let's say it's for general forest residue chips (biofuel). Perhaps the question is vague, but I am not sure. I am still new to the site, so I am not sure if this is an appropriate tag, at least it's close to what I am working with. I have the most data I need, but I couldn't find a formula to calculate the dust concentration of a certain biofuel which would be acquired with the help of the data I have.

• I don't think it can be calculated. Measured? Yes.
– Gert
Commented Jun 27, 2020 at 15:49
• Oh, okay; thank you for your input. I already have measured the before and after for the weight of the cartridge; dry mesh bag (with contains silica gel); the condensate bottle. I also have, with the help of gas volume meter measured the ambient temperature and the before and after count of the normal cubic meter on the gas volume meter. Honestly, I am still not sure. Nonetheless, I still appreciate the information you've given me. I am specifically talking about particulate matter.
– Qwin
Commented Jun 27, 2020 at 15:56
• I've removed a number of comments that were attempting to answer the question and/or responses to them. Please keep in mind that comments should be used for suggesting improvements and requesting clarification on the question, not for answering. Commented Jun 28, 2020 at 1:56

To measure the dust concentration, run a known amount of dust-laden air over an adequate dust filter. Measure the filter's weight at the start, $$w_0$$, and at the end, $$w_1$$, of the run. The volume run over the filter during the run is $$V_N$$ (converted to Normal volume).

The dust concentration is:

$$c=\frac{w_1-w_0}{V_N}$$

• I have: Weight of the cartridge with glass fibre filters: before: 50.6123 g; after measurement and re-drying: 50.6978 g Weight of the dry mesh bag (with silica gel): 1171.35 g Weight of the mesh bag (with silica gel) after measurement: 1176.56 g Weight of the empty condensate bottle: 1462.18 g Weight of the condensate bottle with condensed water after the measurement: 1642.23 g Ambient temperature: 39 °C Air count before measurements: 251.325 $Nm^3$ Air count after measurements: 259.123 $Nm^3$ Is this correct?: $$C = \frac{50.6978-50.6123}{259.123-251.325}$$
– Qwin
Commented Jun 27, 2020 at 16:34
• Looks A-OK to me. Thanks for the upvote!
– Gert
Commented Jun 27, 2020 at 16:53
• You are assuming that all the dust is captured by the filter. Is that valid? You might have to figure out what fraction of the dust gets through, and modify your calculation to account for it. Commented Jun 27, 2020 at 17:36
• I wrote: adequate dust filter.
– Gert
Commented Jun 27, 2020 at 17:38
• +1. So you did. Commented Jun 27, 2020 at 17:40