Five days after it had been introduced, the Legislature voted 26-14 on May 13 to pass Senator Raikes’ amendment which stripped Tobacco Free Nebraska of the $3 million it was to receive annually from the General Fund. There was no evidence that the tobacco industry directly lobbied for this amendment. Because this amendment dealt exclusively with the funding of a tobacco control program, if the tobacco industry had done so it would have constituted a violation of the Master Settlement Agreement.The tobacco industry, however, has a long history of using allies and third parties to lobby on its behalf on such matters.The passage of Senator Raikes’ amendment rendered a similar amendment, introduced by Philip Erdman of Bayard , which would also have stripped Tobacco Free Nebraska’s funding out of the budget moot. As of May 13, 2003, Tobacco Free Nebraska had been zeroed out by the Nebraska Legislature. With the possibility of receiving funding out of the tobacco settlement looking slim,vertical farming company tobacco control advocates focused their efforts in support of Senator Bromm’s amendment to increase the cigarette excise tax by $0.03 to fund Tobacco Free Nebraska. The tobacco industry and its allies were permitted by the Master Settlement Agreement to lobby against excise tax increases so they did lobby strongly in opposition to Senator Bromm’s amendment to LB 759. On May 15, Senator Bromm’s amendment was defeated when if failed by two votes to garner the 25 votes necessary to pass an amendment.
Especially disheartening for tobacco control advocates was that six senators were not present for the vote. Only one of these senators was strongly pro-tobacco industry, Jim Cudaback of Riverdale and two of these senators, Ray Aguilar of Grand Island and DiAnna Schimek of Lincoln , who would have almost certainly voted in favor of the amendment had they been present. These two senators and Senator Vickie McDonald of Rockville later voted in favor of an almost identical amendment to raise the tobacco excise tax by $0.03 to fund Tobacco Free Nebraska. During the vote on Senator Bromm’s amendment, Senator Aguilar was at a doctor’s appointment, Senator Schimek was out of the state and Senator McDonald had left the floor of the Legislature over a comment made about her deceased husband. Because the vote on Senator Bromm’s amendment was so close, Senator Thompson introduced an almost identical amendment, AM 7153, to get funding to Tobacco Free Nebraska through a $0.03 excise tax increase, but this amendment failed byAir pollution can cause a number of both acute and chronic health problems1 . Air pollution has many components which vary from particulate matter , heavy metals, persistent organic pollutants, and gaseous pollutants among others. It is important to monitor these levels to identify when they pose a risk to human health and when action must be taken. Government agencies such as the American Environmental Protection Agency and the European Directorate-General for Environment regulate outdoor standards for some macro components of air such as ozone, sulfur dioxide, and nitrogen dioxide. However, they do not regulate the indoor environment where people now spend at least 80% of their time . Indoor environments can have high levels of air pollution from sources such as cooking, smoking, air cleaning devices, building materials, biological air pollutants from pets and even radioactive pollutants such as radon from granite/gneiss flooring and decorations. VOCs represent a form of air pollution that warrants further study as they are typically in greater concentrations in indoor environments where there often are no regulations regarding exposure limits.
Additionally, high levels of VOCs are associated with health problems such as asthma and other negative respiratory effects. Monitoring the trace levels of VOCs in air is essential due to the possible risks they can cause towards humans health. Several trace chemical detection techniques have emerged in the past decades to address this concern. The manufacturers of these chemical sensors have targeted lowering the production cost, miniaturizing sensors for portability and increasing detection capabilities. Commercially available gas phase chemical sensors are usually either electrochemical, metal oxide semiconductor , light detecting such as infrared , or photo ionization based detectors. However each of these devices has pros and cons, and each has a narrow range of chemicals that can be detected. Compared to advanced analytical techniques, these limitations have dampened the applicability of these detectors for personal VOC exposure monitoring. Traditional analytical techniques such as gas chromatography and mass spectrometry provide superior detection limits, chemical specificity and a wider range of chemicals detected over those other sensors. However, the high manufacturing and operating costs as well as the large size and weight of GC-MS systems are major obstacles for mobile air quality monitoring applications. Regardless of chemical sensor type, the low levels of VOCs present in air make it challenging to detect air pollutant VOCs without the use of proper sampling techniques. Often, chemical analysis includes a preconcentration step, in which a device traps and concentrates VOCs from air samples over a desired duration to achieve improved limits of detection. Custom fabricated preconcentrator chips are versatile, as they can be married to micro-electromechanical -based chemical sensors for a completely mobile detection system, or preconcentrators can be returned to the laboratory for benchtop analysis, such as GC-MS.
Such preconcentrators have been tested for different applications in the past. However, no study has been conducted to use a gas preconcentrator in a handheld or wearable device to trap VOCs directly in the personal user environment. In this work, we report a portable and wearable custom-built environmental sampler that contains a preconcentrator chip. Design emphasis was placed on a lightweight, wearable sampler to collect the VOCs exposed to the wearing user. The sampler is programmable, allowing adjustments to sampling time and flow rate. To collect VOC samples, the device uses our previously described micro preconcentrator chips, which can easily be replaced by users to collect multiple samples in a single exposure time period18. Samples in our study were returned to the laboratory for GC-MS analysis, but the sampler could be married to mobile chemical sensing platforms for real-time analysis in the future.We used a previously published microfabricated sorbent chip in our newly described wearable system. Briefly, a chip is created using traditional photolithography and etching into a glass substrate. Resistive heaters are patterned onto the back side of the device allowing for rapid heating and desorption of VOCs. Tenax TA sorbent is packed into the chip,vertical farming systems which allows for broad spectrum sampling and quantification of many VOCs of interest. The chip can be tailored with other sorbents if specific chemical sampling is desired, which was outside the scope of this current work.We designed an environmental sampler light enough to be worn with micro gas preconcentrator chips that can be easily swapped for multiple sample collections and be programmed for varying sample durations and flow rates. The sampler is housed in a modified aluminum case . A custom aluminum-fixture houses the microfabricated chip. The fixture consists of top and bottom halves that are held together with 4× 6–32thumbscrews that enable easy and rapid opening and closing. The top half has a 2.54 cm cutout to align the microfabricated chip that rests on 2× 006 PTFE O-rings . The bottom half attaches to the system housing and has two spring-loaded custom PTFE transfer lines that make contact with the microfabricated chip via 006 Viton® O-rings . The spring-loaded nature of the transfer lines allows them to adjust to the microfabricated chip, which creates an airtight seal on the inlet and outlet of the chip while also prevent excessive pressure on the chip that could shatter it. Both transfer lines connect to 1.59 mm OD PTFE tubing via 1.59 mm NPT to 1.59 mm compression fitting adapters . While the inlet line is directly exposed to the environmental air, the outlet line connects to a 10 micron filter to remove any potential particulate that might clog the sampling pump . The end of the filter connects to the sampling pump via 238 mm ID silicone tubing through use of a 10–32 O-ring lined tubing adapter .
The system is controlled by an Adafruit Feather microcontroller with built in microSD card slot and is powered by a 3.7 V, 2500 mAH rechargeable lithium ion polymer battery . GPS data is collected via a GPS antenna and the Adafruit Ultimate GPS Feather Wing . Additionally, there is a custom PCB that connects the micro-controller to the sampling pump motor driver and temperature and humidity sensor to collect ambient conditions. A belt clip is attached to the housing to allow for the device to be worn during operation. The micro-controller records the data to the SD card, communicates with the GPS and temperature and humidity sensor and controls the sampling pump. With the sampling pump operating at a 50% duty cycle, the system consumes ~64 mA of current and reduces to ~48 mA when the sampling pump is off. With the current battery, the device is estimated operate between 39 and 52 h per charge. The Adafruit feather has built in battery charging circuitry so the battery can be charged via any USB connection such as with a computer or wall outlet. The environmental sampler can be programmed to operate in a variety of different modes. For this study the sampler updates the GPS, temperature and humidity readings every 10 sec and only saves this data to the SD card during sampling. The sampling flow rate is set by the duty cycle of the pulse width modulation signal sent to the motor driver board, which was set to a 50% duty cycle for a sampling flow of ~80 mL/min, verified using an electronic flow meter The device sampling time and rate are easily adjusted in the code and can be set to either sample periodically throughout the day or for a single duration. The sampler can be programmed in the Arduino IDE which enables quick and easy reprogramming of the device. To verify the sampler performance, a series of tests was first conducted inside the laboratory. The sampling inlet of the environmental sampler was connected to 3 L Tedlar® bags . The Tedlar® sampling bags were prepared with varying concentrations of chemical standards, obtained from typical commercial vendors, diluted in air. With a volume of 3 L, multiple samples could be taken from the same bag, reducing error from sample preparation. Sampling times, sample concentrations and VOCs varied by test . The sampler was used by laboratory researchers in settings to mimic expected use, including samples taken around the UC Davis campus and in researchers’ homes. Sampling time varied, including tests of letting the sampler run for 1 h nonstop, or for several minutes each hour over the course of 8–12 h. Under IRB approval by the University of California, Davis campus , the sampler was given to a 17 year old high school student volunteer. The student was given instructions on how to change the preconcentrator chips in the sampler and was asked to change the chip once a day for 5 d. A total of 5 samples were collected from this participant. During each sample, the sampler engaged for 10 min each hour for 12 h during the day .After sample collection, the μPCs were removed from the environmental sampler and loaded onto a custom built test fixture connected to the mass spectrometer, previously described. Briefly, an aluminum fixture was fabricated to hold and heat the chip to 260 °C for a total desorption time of 15 min. A flow of 25 mL/min of helium carried desorbed VOCs from the μPC through a borosilicate transfer line and into the inlet of a GC-MS . The inlet was set to splitless mode at 235 °C. After desorption, the column , initially at 40 °C, heated at 10 °C/min to 170 °C, then heated at 30 °C/min to 250 °C, holding for 6 min. Helium flow was set to constant flow . The mass spectrometer scanned from 35 to 249 m/z. Data files were deconvoluted using AMDIS and aligned using Agilent’s Genespring . Putative identification of compounds was made by comparison of extracted mass spectra to the NIST ‘14 MS database. Calibration curves were built to quantify the grams of VOCs retained onto the μPC chip during sampling.