Solutions of compound 1 exhibit dramatic, characteristic color changes in response to sugar analytes. Structurally related saccharides including glucose phosphates and amino and carboxylic acid sugars can be readily distinguished by visual inspection. These findings should promote the design of unique color sensory materials based on readily available, functional macrocyclic hosts.

Diverse urban air pollution sources contribute to spatially variable atmospheric concentrations, with important public health implications. Mobile monitoring shows promise for understanding spatial pollutant patterns, yet it is unclear whether uncertainties associated with temporally sparse sampling and instrument performance limit our ability to identify locations of elevated pollution. To address this question, we analyze 9 months of repeated weekday daytime on-road mobile measurements of black carbon (BC), particle number (PN), and nitrogen oxide (NO, NO 2 ) concentrations within 24 census tracts across Houston, Texas. We quantify persistently elevated, intermittent, and extreme concentration behaviors at 50 m road segments on surface streets and 90 m segments on highways relative to median statistics across the entire sampling domain. We find elevated concentrations above uncertainty levels (±40%) within portions of every census tract, with median concentration increases ranging from 2 to 3× for NO 2 , and >9× for NO. In contrast, PN exhibits elevated concentrations of 1.5−2× the domainwide median and distinct spatial patterns relative to other pollutants. Co-located elevated concentrations of primary combustion tracers (BC and NO x ) near 30% of metal recycling and concrete batch plant facilities within our sampled census tracts are comparable to those measured within 200 m of highways. Our results demonstrate how extensive mobile monitoring across multiple census tracts can quantitatively characterize urban air pollution source patterns and are applicable to developing effective source mitigation policies.

There is limited field data that can be used for fuel use and emissions analyses of nonroad diesel construction equipment. This paper summarizes the results of field research that used a portable emission monitoring system (PEMS) to collect fuel use and emissions data from eight backhoes, six bulldozers, three excavators, four generators, six motor graders, three off-road trucks, one skid-steer loader, three track loaders, and five wheel loaders while they performed various duty cycles. These tests produced approximately 119 hours of field data for petroleum diesel and approximately 48 hours for B20 biodiesel. Engine attribute data including horsepower, displacement, model year, engine tier, and engine load were measured to determine their influence on fuel use rates and emission rates of NO x , HC, CO, CO 2 , and opacity. Mass per time fuel use rates were developed for each item of equipment as well as mass per time and mass per fuel used emission rates for each pollutant. For petroleum diesel, fuel use and emission rates of each pollutant were found to increase with engine displacement, horsepower, and load, and to decrease with model year and engine tier. The results were qualitatively similar for B20. Fuelbased emission rates were found to have less variability and less sensitivity to engine size and load than time-based emission rates. Hence, where possible, development of emission inventories based on fuel consumed, rather than time of activity, is preferred.

A study design was developed and demonstrated for deployment of a portable emission measurement system (PEMS) for excavators. Excavators are among the most commonly used vehicles in construction activities. The PEMS measured nitric oxide, carbon monoxide, hydrocarbons, carbon dioxide, and opacity-based particulate matter. Data collection, screening, processing, and analysis protocols were developed to assure data quality and to quantify variability in vehicle fuel consumption and emissions rates. The development of data collection procedures was based on securing the PEMS while avoiding disruption to normal vehicle operations. As a result of quality assurance, approximately 90% of the attempted measurements resulted in valid data. On the basis of field data collected for three excavators, an average of 50% of the total nitric oxide emissions was associated with 29% of the time of operation, during which the average engine speed and manifold absolute pressure were significantly higher than corresponding averages for all data. Mass per time emission rates during non-idle modes (i.e., moving and using bucket) were on average 7 times greater than for the idle mode. Differences in normalized average rates were influenced more by intercycle differences than intervehicle differences. This study demonstrates the importance of accounting for intercycle variability in real-world in-use emissions to develop more accurate emission inventories. The data collection and analysis methodology demonstrated here is recommended for application to more vehicles to better characterize real-world vehicle activity, fuel use, and emissions for nonroad construction equipment.

Field data for in-use fuel consumption and emission rates were collected for 15 nonroad vehicles using a portable emission measurement system (PEMS). Each vehicle, including 5 backhoes, 4 front end loaders, and 6 motor graders, were tested once on petroleum diesel and once on B20 biodiesel. The vehicles include different model years and thus represent a variety of engine certification tiers. A methodology was developed for study design, field data collection, data screening and quality assurance, data analysis, and benchmarking of the data. The average rate of loss of data due to data quality issues was 6.9 percent. On average, over 3 hours of valid data were collected in each test. Time-based emission factors were found to increase monotonically with respect to engine manifold absolute pressure. Fuel-based emission factors were mainly sensitive to differences between idle and non-idle engine operation. Typical duty cycles were quantified in terms of frequency distributions of manifold absolute pressure (MAP) and used to estimate cycle average emission factors. On average, the use of B20 instead of petroleum diesel lead to an insignificant 1.8 percent decrease in NO emission rate and significant decreases of 18, 26, and 25 percent for opacity, HC, and CO, respectively. Emission rates were also found to decrease significantly when comparing newer, higher tier vehicles to older ones. Fuel use, NO, HC, and CO data were found to be of similar magnitude as independent benchmark data. Specific recommendations are made for future work.