The gas measurement device includes a filter having a plurality of openings, each opening being variable in size, an adjustment mechanism configured to vary size of the plurality of openings, a first gas sensor configured to detect gas molecules passing through an opening of the filter and output a first measurement value corresponding to the detected gas molecules, and a second gas sensor configured to detect the gas molecules passing through the opening of the filter, output a second measurement value corresponding to the detected gas molecules, and detect gas molecules of a gas species different from the gas molecules detected by the second gas sensor.

A conditioning system for a filter module is disclosed. The conditioning system may generally include an inlet, a heat exchanger, a magnetically levitated pump, a channel provided to bypass the heat exchanger, a controller, an outlet, and a base. The system may have components lined with corrosion-resistant materials. A method of conditioning a filter module is also disclosed. The method may generally include measuring TOC in a source of ultrapure water, heating the ultrapure water, rinsing a filter module with the heated water, flushing the filter module with ambient temperature water, and repeating the rinsing with heated water and flushing with ambient temperature water. A method of facilitating conditioning of the filter module is also disclosed. The method may generally include providing a portable filter module conditioning system and providing instructions for installation or use.

A method for estimating and utilizing ultrafine particle concentration includes: receiving data indicative of a measured ultrafine particle concentration and a measured nitrogen oxide concentration correlated to each location of a plurality of locations and a corresponding time of a plurality of times; establishing a correlation between ultrafine particle concentration and nitrogen oxide concentration from the measured ultrafine particle concentrations and the measured nitrogen oxide concentrations; estimating, from a nitrogen oxide concentration measured at a location where the ultrafine particle concentration is to be estimated, the ultrafine particle concentration according to the correlation; and comparing the estimated ultrafine particle concentration with at least one ultrafine particle concentration threshold to determine whether the estimated ultrafine particle concentration is higher or lower than the at least one ultrafine particle concentration threshold.

This document describes a system and method for enumerating a concentration of microorganism in a liquid sample. The disclosed system has a filtration medium that has an inlet for receiving the liquid sample and an outlet for removing a filtered liquid sample from the filtration medium. A differential pressure sensor having a first port connected to the inlet of the filtration medium and a second port connected to the outlet of the filtration medium is also provided in this system and the differential pressure sensor is configured to measure a pressure difference between the inlet and outlet of the filtration medium over a period. The system also has a computing module that is communicatively connected to the differential pressure sensor whereby the computing module is configured to enumerate the concentration of the microorganism in the liquid sample based on the measured pressure difference over the period and a pre-generated calibration model.