Abstract: A system includes a first and second condensation particle counter, each counter having an inlet port, a growth column, and an optical element for counting particles detected at the respective inlet ports. The counters are configured to include a wick in which the wick is wetted by water. A differential pressure sensor is coupled to the first inlet port and coupled to the second inlet port. The sensor is configured to provide a pressure signal. A processor is coupled to memory and configured to receive the first signal, the second signal, and the pressure signal and generate an output corresponding to a ratio of the first signal and the second signal and correlate the ratio with the pressure signal. A housing is configured to receive the first counter, the second counter, the differential pressure sensor, the processor, and the memory.

Abstract: A particle growth apparatus includes a temperature-controlled humidifier coupled to a water-based condensation growth system. The humidifier may include a tube of sulfonated tetrafluoroethylene-based fluoropolymer-copolymer and surrounded by a region containing water or water vapor. The apparatus includes a wetted wick and wick sensor in the condensation growth system, configured such that the gas sample flows through the sulfonated tetrafluoroethylene-based fluoropolymer-copolymer tube into the condensation growth system.

Abstract: A system includes a first and second condensation particle counter, each counter having an inlet port, a growth column, and an optical element for counting particles detected at the respective inlet ports. The counters are configured to include a wick in which the wick is wetted by water. A differential pressure sensor is coupled to the first inlet port and coupled to the second inlet port. The sensor is configured to provide a pressure signal. A processor is coupled to memory and configured to receive the first signal, the second signal, and the pressure signal and generate an output corresponding to a ratio of the first signal and the second signal and correlate the ratio with the pressure signal. A housing is configured to receive the first counter, the second counter, the differential pressure sensor, the processor, and the memory.

Abstract: An apparatus and method for the delivery and deposition of particles air-liquid-interface (ALI) cell cultures includes a sample inlet coupled to a growth tube having interior walls that are wet. The growth tube is configured to operate at a first temperature along a first length of the tube and a second temperature along a second length positioned between the first length and a growth tube outlet. The apparatus also includes a nozzle plate having a plurality of nozzles. The exposure chamber adapted to hold cell cultures at an air-liquid interface positioned underneath the plurality of nozzles and a temperature regulator adapted to control a temperature of the exposure chamber. The apparatus also includes a controller including instructions operable to cause the controller to maintain a relative humidity within the exposure chamber by controlling at least the second temperature of the growth tube and the temperature of the exposure chamber.

Abstract: A particle growth apparatus includes a temperature-controlled humidifier coupled to a water-based condensation growth system. The humidifier may include a tube of sulfonated tetrafluoroethylene-based fluoropolymer-copolymer and surrounded by a region containing water or water vapor. The apparatus includes a wetted wick and wick sensor in the condensation growth system, configured such that the gas sample flows through the sulfonated tetrafluoroethylene-based fluoropolymer-copolymer tube into the condensation growth system.

Abstract: A system and a method is described herein for the collection of small particles in a concentrated manner, whereby particles are deposited onto a solid surface or collected into a volume of liquid. The collected samples readily interface to any of a number of different elemental, chemical, or biological or other analysis techniques.

Abstract: A system and a method is described herein for the collection of small particles in a concentrated manner, whereby particles are deposited onto a solid surface or collected into a volume of liquid. The collected samples readily interface to any of a number of different elemental, chemical, or biological or other analysis techniques.