Rationale: Ambient particulate concentrations have been associated with variable physiologic effects in children with persistent asthma taking controller medications.Objective: To determine whether exposure to particulate matter has immediate effects on asthma control in children with persistent disease.Methods and Measurements: In a school-based cohort, 73 children, primarily with moderate and severe asthma, were followed daily over one or two winters (2001–2002, 2002–2003) in Denver, Colorado. The association among ambient fine particulate, bronchodilator use, and urinary leukotriene E4 levels was assessed.Results: Daily concentrations of fine particulate peaked in the morning hours when children were commuting to school. In a multivariable analysis that controlled for meteorology, time trends, and upper respiratory infections, an increase of one interquartile range in morning maximum fine particulate levels was related to an average increase of 3.8% in bronchodilator usage at school (95% confidence int...

https://www.atsjournals.org/doi/pdf/10.1164/rccm.200509-1393OC

Particulate levels are associated with early asthma worsening in children with persistent disease.

We report simultaneous measurements of fuel consumption, driving patterns, and CO2, CO, and NOx emission factors for diesel passenger buses under real operating conditions in high altitude cities (>2000 masl) and in mountainous regions with an average road grade of 4%. These measurements were obtained using a Portable Emission Measurement System (PEMS) monitoring a sample of 15 buses during eight months of daily operation. For a city with a high level of vehicular traffic (Mexico City), we obtained an average fuel consumption of 0.41 L/km and emission factors of 965.8, 41.4, and 5.3 g/km for CO2, CO, and NOx, respectively. Fuel consumption and CO2 emissions were within expected values. However, CO emissions were approximately three times higher while the NOx emission were half of the reported values in the literature for buses of similar technology working at low altitude.

Real emissions, driving patterns and fuel consumption of in-use diesel buses operating at high altitude

Particulate matter mass measurements for low emitting diesel powered vehicles: what's next?

Recently there has been a rapid increase in approaches to assess the effects of cigarette smoke in vitro. Despite a range of gravimetric and chemical methods, there is a requirement to identify simpler and more reliable methods to quantify in vitro whole smoke dose, to support extrapolation and comparisons to human/in vivo dose. We have previously characterised an in vitro exposure system using a Borgwaldt RM20S smoking machine and a chamber exposing cellular cultures to whole smoke at the air-liquid interface. In this study we demonstrate the utility of a quartz crystal microbalance (QCM), using this exposure system, to assess real-time cigarette smoke particulate deposition during a 30 minute smoke exposure. Smoke was generated at various dilutions (1:5–1:400, smoke:air) using two cigarette products, 3R4F Kentucky reference and 1 mg commercially available cigarettes. The QCM, integrated into the chamber, assessed particulate deposition and data generated were compared to traditional chemical spectrofluorometric analysis. The QCM chamber was able to detect mass differences between the different products within the nanogram range. 3R4F reference cigarette smoke deposition ranged from 25.75 ±2.30 μg/cm2 (1:5) to 0.22 ±0.03 μg/cm2 (1:400). 1 mg cigarette smoke deposition was less and ranged from 1.42 ±0.26 μg/cm2 (1:5), to 0.13 ±0.02 μg/cm2 (1:100). Spectrofluorometric analysis demonstrated statistically significant correlation of particulate deposition with the QCM (p < 0.05), and regression R2 value were 97.4 %. The fitted equation for the linear model which describes the relationship is: QCM = −0.6796 + 0.9744 chemical spectrofluorescence. We suggest the QCM is a reliable, effective and simple tool that can be used to quantify smoke particulate deposition in real-time, in vitro and can be used to quantify other aerosols delivered to our chamber for assessment.

/pdf/real-time-assessment-of-cigarette-smoke-particle-deposition-4fbpx3rxdo.pdf

Real-time assessment of cigarette smoke particle deposition in vitro

Idle emissions data from 19 medium heavy-duty diesel and gasoline trucks are presented in this paper Emissions from these trucks were characterized using full-flow exhaust dilution as part of the Coordinating Research Council (CRC) Project E-55/59 Idle emissions data were not available from dedicated measurements, but were extracted from the continuous emissions data on the low-speed transient mode of the medium heavy-duty truck (MHDTLO) cycle The four gasoline trucks produced very low oxides of nitrogen (NOx) and negligible particulate matter (PM) during idle However, carbon monoxide (CO) and hydrocarbons (HCs) from these four trucks were approximately 285 and 153 g/hr on average, respectively The gasoline trucks consumed substantially more fuel at an hourly rate (084 gal/hr) than their diesel counterparts (044 gal/hr) during idling The diesel trucks, on the other hand, emitted higher NOx (79 g/hr) and comparatively higher PM (41 g/hr), on average, than the gasoline trucks (38 g/hr of NOx and 09 g/hr of PM, on average) Idle NOx emissions from diesel trucks were high for post-1992 model year engines, but no trends were observed for fuel consumption Idle emissions and fuel consumption from the medium heavy-duty diesel trucks (MHDDTs) were marginally lower than those from the heavy heavy-duty diesel trucks (HHDDTs), previously reported in the literature

https://www.tandfonline.com/doi/pdf/10.3155/1047-3289.59.3.354

Idle Emissions from Medium Heavy-Duty Diesel and Gasoline Trucks

We determined the usefulness of tapered element oscillating microbalances (TEOMs) for researchers and engineers involved with measuring diesel particulate mass. Two different test facilities were used for generating diesel particulates and comparing the TEOM to the commonly used U.S. Environmental Protection Agency (EPA) manual filter method. The EPA method is very labor-intensive and requires long periods of time to complete. The TEOM is an attractive approach because it has the potential to reduce the amount of time and labor required in diesel testing, as well as to provide real-time particulate-mass data that are not obtainable with the EPA method. It was found that the TEOM was a precise and easy-to-operate instrument that could measure the mass concentration (MC) of diesel particulate emissions in real time. Although the TEOM diesel particulate MC measurements were highly correlated with the manual filter measurements, the two techniques were not equivalent because the TEOM consistently reported MC results that were 20-25% lower than those obtained using the manual filter technique. In conclusion, the TEOM can be used to increase test-cell throughput and to measure transient values of diesel particulate emissions at sites performing diesel-engine testing. However, unless EPA is able to certify the TEOM as an equivalent method, it cannot replace the manual filter method for diesel certification work.

https://www.tandfonline.com/doi/pdf/10.1080/10473289.2002.10470875

An evaluation of the tapered element oscillating microbalance method for measuring diesel particulate emissions

A system is configured to control aerodynamics of a vehicle. The vehicle includes a vehicle body having a front end facing an ambient airflow when the vehicle is in motion relative to a road surface. The system includes an adjustable aerodynamic-aid element mounted to the vehicle body. The system also includes a mechanism configured to vary a position of the adjustable aerodynamic-aid element relative to the vehicle body and thereby control movement of the airflow. The system additionally includes a sensor configured to detect a height of the vehicle body relative to a predetermined reference frame and a controller configured to receive a signal from the sensor indicative of the detected vehicle body height. The controller is also configured to determine a ride-height of the vehicle using the detected vehicle body height and to regulate the mechanism in response to the determined ride-height to control aerodynamics of the vehicle.

Vehicle ride-height determination for control of vehicle aerodynamics

This paper describes the design and functionality of an in-situ air entrainment measuring device for analysis of the air entrainment and air release properties of lubricating fluids. The apparatus allows for a variety of measurement techniques for the aeration and deaeration of the lubricating fluid at various temperatures, pressures, and agitation speeds. This test apparatus is patent pending because of its unique ability to allow for continuous, in-situ measurement of the fluid properties and the rates of change of these properties. Most other measurement techniques and apparatuses do not allow for uninterrupted measurement, This apparatus is also unique in that it is capable of detecting minor fluid density changes at a lower level and with more accuracy than all other current techniques or apparatuses.

A New Method of Measuring Aeration and Deaeration of Fluids

A vehicle has first and second portions, with a front aerodynamic element located in the first portion and a rear aerodynamic element located in the second portion. The front and rear aerodynamic elements are each independently movable to respective deployment positions between respective stowed positions and respective fully-extended positions. A controller is operatively connected to each of the front and rear aerodynamic elements and has a processor and tangible, non-transitory memory. The controller is programmed to obtain a front target position (T f,n ) for the front aerodynamic element at a current time step (n) based at least partially on at least one vehicle state parameter at a previous time-step (n−1) and a detected position (D r,n-1 ) of the rear aerodynamic element at the previous time-step (n−1).

Determination of aerodynamic actuation commands

A test apparatus for measuring the air entrainment characteristics of a fluid includes a reservoir for containing the fluid, an aerator apparatus to cause air entrainment of the fluid, and a density meter to measure the effects of air entrainment on fluid density. The test apparatus enables in-situ measurement of the transient air entrainment behavior of the fluid. A corresponding method is provided.

Fluid aeration test apparatus and method

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