DC1100 made by Dylos, a branch name for carpet cleaner and vacuum, is powered with a 9V-wall plug. A recent update of DC1100 is DC1700 with battery and EMF shield. A "Pro" version indicated for the lowest size of the particle is 0.25µm and a normal version is duller with 0.5µm as the lower end. The maker limits the product's use to "detect levels of airborne particulates" and not to "health impacts for any given individual". To correlate the particle counts to the health impacts, I need to refer different sources.
I will work through 5 sources to correlate small particle counts with the concencentration of fine particle (PM_{2.5}).
Assumed that the particle density (ρ) is 1.65E+12 µg/m^{3} and for the fine particle collection, the representative radius is 0.44µm. Then the mass of one particle is:
$m=\rho\times(\frac{4}{3}\pi\text(r)^3)$ $=(1.65\times10^{12}(\frac{\mu g}{\text(m^3)}))\times(\frac{4}{3}\pi(0.44\times10^{-6}\text(m^3))$ $=(5.89\times10^{-7})\text(\mu g)$DC1100 displays the small particle on the left and the large one on the right per 0.01 ft^{3}. To get the number of particles lower than 2.5µm in radius, and convert to per m^{3}
$\text{#p=(small-large)}\times3531(\frac{0.01ft^3}{m^3})$Finally, the mass of fine particles (PM_{2.5}) per a volume of air can be calculated by:
$\text{PM}_{2.5}\text{ = #p}\times\text{m}$ $\text{ = (small-large)}\times3531\times5.89\times10^{-7}$ $\text{=(small-large)}\times2.08\times10^{-3}(\frac{\mu g}{m^3})$
Check the source of assumptions:
On myhealthbeijing.com listed a speadsheet correlating Dylos raw readings with a AQI. Additional information on using DC1100 as a PM_{2.5} the fitting monitor are linked here. The fitting are expressed by the below equation:
$\text{AQI}_{US}\text{ = }3.31\times10^{-22}\text{x}^5 - 1.04\times10^{-16}\text{x}^4$ $+1.19.10^{-11}\text{x}^3 - 5.85 10^{-07}\text{x}^2 + 0.016\text{x}+9.43$with goodness-of-fitting r^{2} = 0.999. Using the breakpoints given by US EPA, PM_{2.5} can be back-calculated.
The author on this site claimed that the estimation was obtained from Dylos Corporation with a link to DC1100's patent. There is no other source to confirmed this approach. I emailed the custommer service at Dylos inquirying the PM_{2.5} to AQI conversion to no avail. This simple estimation is:
$\text{PM}_{2.5}\text{ = (small-large)/100}(\frac{\mu g}{m^3})$The following equations are obtained by AQ-SPEC, an entity belonged to US EPA that done extensively testing with low-cost PM_{2.5} monitors.
An fitting equation between counting particle between 0.5-2.5µm (x) with DC1100 Pro version and an FEM monitor GRIMM EDM-180 with r^{2}=0.815.
$\text{PM}_{2.5}=-8\times10^{-12}\text{x}^2+5\times10^{-05}\text{x}+3.98$Similar to the approach with EDM-180, the following equation is the fittings with another FEM monitor, MetOne BAM-1020 with r^{2}=0.632.
$\text{PM}_{2.5}=-1\times10^{-11}\text{x}^2+4\times10^{-05}\text{x}+4.17$