Microfabricated particulate matter monitor

An apparatus for measuring concentrations of airborne particulate matter, the apparatus comprising:

• a primary channel to receive air samples from an external environment, the air samples comprising particles of varying sizes;
• a microfluidic circuit communicating with the primary channel, wherein particles having a size less than a threshold size are diverted around a bend into a secondary channel in communication with the primary channel, while remaining particles having a size larger than the threshold size and unable to make the bend continue through the primary channel;
• and
• a mass-sensitive element communicating with the secondary channel and comprising a collection surface to collect the particles having a size less than the threshold size, wherein a resonant frequency of the mass-sensitive element is reduced in proportion to the mass of the particles collected;
• wherein the secondary channel extends between first and second ends, the first and second ends both coupled to the primary channel having the mass-sensitive element communicating with the secondary channel between the first and second ends.