An improved, automated whole air sampler and gas chromatography mass spectrometry analysis system for volatile organic compounds in the atmosphere

Volatile organic compounds were quantified during two aircraft-based field campaigns using highly automated, whole air samplers with expedited post-flight analysis via a new custom-built, field-deployable gas chromatography-mass spectrometry instrument. During flight, air samples were pressurized with a stainless steel bellows compressor into electropolished stainless steel canisters. The air samples were analyzed using a novel gas chromatograph system designed specifically for field use which eliminates the need for liquid nitrogen. Instead, a Stirling cooler is used for cryogenic sample pre-concentration at temperatures as low as 165 degrees C. The analysis system was fully automated on a 20 min cycle to allow for unattended processing of an entire flight of 72 sample canisters within 30 h, thereby reducing typical sample residence times in the canisters to less than 3 days. The new analytical system is capable of quantifying a wide suite of C2 to C10 organic compounds at part-per-trillion sensitivity. This paper describes the sampling and analysis systems, along with the data analysis procedures which include a new peak-fitting software package for rapid chromatographic data reduction. Instrument sensitivities, uncertainties and system artifacts are presented for 35 trace gas species in canister samples. Comparisons of reported mixing ratios from each field campaign with measurements from other instruments are also presented.</p

Volatility and lifetime against OH heterogeneous reaction of ambient isoprene-epoxydiols-derived secondary organic aerosol (IEPOX-SOA)

Isoprene-epoxydiols-derived secondary organic aerosol (IEPOX-SOA) can contribute substantially to organic aerosol (OA) concentrations in forested areas under low NO conditions, hence significantly influencing the regional and global OA budgets, accounting, for example, for 16-36% of the submicron OA in the southeastern United States (SE US) summer. Particle evaporation measurements from a thermodenuder show that the volatility of ambient IEPOX-SOA is lower than that of bulk OA and also much lower than that of known monomer IEPOX-SOA tracer species, indicating that IEPOX-SOA likely exists mostly as oligomers in the aerosol phase. The OH aging process of ambient IEPOX-SOA was investigated with an oxidation flow reactor (OFR). New IEPOX-SOA formation in the reactor was negligible, as the OFR does not accelerate processes such as aerosol uptake and reactions that do not scale with OH. Simulation results indicate that adding ∼ 100µgm-3 of pure H2SO4 to the ambient air allows IEPOX-SOA to be efficiently formed in the reactor. The heterogeneous reaction rate coefficient of ambient IEPOX-SOA with OH radical (kOH) was estimated as 4.0±2.0 × 10-13cm3molec-1s-1, which is equivalent to more than a 2-week lifetime. A similar kOH was found for measurements of OH oxidation of ambient Amazon forest air in an OFR. At higher OH exposures in the reactor (> 1 × 1012moleccm-3s), the mass loss of IEPOX-SOA due to heterogeneous reaction was mainly due to revolatilization of fragmented reaction products. We report, for the first time, OH reactive uptake coefficients (γOH = 0.59±0.33 in SE US and γOH = 0.68±0.38 in Amazon) for SOA under ambient conditions. A relative humidity dependence of kOH and γOH was observed, consistent with surface-area-limited OH uptake. No decrease of kOH was observed as OH concentrations increased. These observations of physicochemical properties of IEPOX-SOA can help to constrain OA impact on air quality and climate

The lifetime of nitrogen oxides in an isoprene-dominated forest

The lifetime of nitrogen oxides (NOx) affects the concentration and distribution of NOx&nbsp;and the spatial patterns of nitrogen deposition. Despite its importance, the lifetime of NOx&nbsp;is poorly constrained in rural and remote continental regions. We use measurements from a site in central Alabama during the Southern Oxidant and Aerosol Study (SOAS) in summer 2013 to provide new insights into the chemistry of NOx&nbsp;and NOx&nbsp;reservoirs. We find that the lifetime of NOx&nbsp;during the daytime is controlled primarily by the production and loss of alkyl and multifunctional nitrates (&Sigma;ANs). During SOAS, &Sigma;AN production was rapid, averaging 90 ppt h-1 during the day, and occurred predominantly during isoprene oxidation. Analysis of the &Sigma;AN and HNO3 budgets indicate that &Sigma;ANs have an average lifetime of under 2 h, and that approximately 45 % of the &Sigma;ANs produced at this site are rapidly hydrolyzed to produce nitric acid. We find that &Sigma;AN hydrolysis is the largest source of HNO3&nbsp;and the primary pathway to permanent removal of NOx&nbsp;from the boundary layer in this location. Using these new constraints on the fate of &Sigma;ANs, we find that the NOx&nbsp;lifetime is 11&thinsp;&plusmn;&thinsp;5 h under typical midday conditions. The lifetime is extended by storage of NOx&nbsp;in temporary reservoirs, including acyl peroxy nitrates and &Sigma;ANs.</p

The development, validation, reliability and norming of the panukat ng pagkamapagbahala

The main goal of this study is to contribute to the filipinization of psychological testing in the Philippines by constructing a paper and pencil instrument. This instrument, the Panukat ng Pagkamapagbahala (PP), measures the level of anxiety trait of Filipinos and determines the sources of their anxiety. Items were constructed based on the data gathered from Filipino respondents regarding the sources of their anxiety. The indigenous method of research, particularly, the pagtatanung-tanong approach was utilized to determine the anxiety sources. Unstructured questionnaires were also distributed to gather data. The items underwent a rigid item review before it was pre-tested. The sample consisted of 150 Filipino adults, within the age range of 21-40 years old. They were equally represented from the government, industrial and educational settings in Metro Manila. The test results were subjected to item analysis and factor analysis. For its final form, the test consists of 44 items, distributed under three factors, namely: Pagkabahala Ukol sa Ekonomiya at Pulitika , Pagkabahala Ukol sa Kalagayang Panlipunan , and Pagkabahala Ukol sa Kapakanan at Kinabukasan . Reliability was established through the coefficient alpha method. Factor I has a reliability coefficient of .9254681 Factor II ha .9182893 and Factor III has a reliability coefficient of .7082398. Four norm tables were constructed using the percentile ranks

A Marketing plan for 1993 of the Metro Ferry

The Pasig River Transit Co., Inc. owns and operates the Metro Ferry, a water transport system which ferries people from Escolta to Guadalupe and vice-versa using the Pasig river. At present, the company has seven riverbuses or vessels in Metro Manila. These operate from 7 am to 7 pm with 30 minute intervals during peak hours and hourly intervals during slack hours. To utilize the riverbuses during slack hours, the company has introduced the Pasig River Educational Tour which takes in students on a charter basis and provides an educational, guided tour of Pasig river aboard the Metro Ferry. The Metro Ferry as a public transport service is being positioned as an alternative mode of transportation in Metro Manila. This mode of transportation is fast, economical and generally pollution-free (from smoke belchers). There is also no long lines, no overcrowding and no traffic. Meanwhile, the Pasig River Educational Tour is positioned as a supplement for classroom learning as it provides students with a historical and ecological experience of the Pasig river. The marketing plan for 1993 focuses on both the Metro Ferry as a public transport system and as a charter service for the Pasig River Educational Tour. Short term objectives include increasing regular passenger ridership by 20% and increasing charter ridership by 50%. A 30% increase in product awareness is also expected. The main thrust of the marketing plan is to increase ridership. To do this, there should be an improvement of the people\u27s image of the Metro Ferry. Hence, an improvement of the quality of service is the main concern. This includes improvements of the Metro Ferry, the crew, the operations, boat signages and the stations. Meanwhile, itineraries, annotations, tour costs, summer packages will be improved to increase the usership of charter services. An increase in tour costs for charter services is recommended to increase the revenues generated from these activities. Likewise, the plan includes the increase of sales force, the provision of sales trainings, the use of sales brochures, clear books and other sales paraphernalia as part of the sales and distribution strategies. It is also recommended that Metro Ferry go into advertising and promotional activities to increase product awareness and usership. Print and radio ads will be used throughout the year. The advertising concept will emphasize Metro Ferry as an alternative mode of transportation where people can avail of a comfortable, economic, fast and hassle-free ride. A series of PR activities have also been prepared to supplement the radio and print ads throughout the year. The PR objective is to create a more favorable image for Pasig river and consequently, for Metro Ferry. Total investments for the marketing plan will amount to P 2,160,408 but profits of P 306,012.46 can be expected. Evaluations will be done quarterly and annually by the marketing and operations manager