Ammonia in the environment: from ancient times to the present

Recent research on atmospheric ammonia has made good progress in quantifying sources/sinks and environmental impacts. This paper reviews the achievements and places them in their historical context. It considers the role of ammonia in the development of agricultural science and air chemistry, showing how these arose out of foundations in 18th century chemistry and medieval alchemy, and then identifies the original environmental sources from which the ancients obtained ammonia. Ammonia is revealed as a compound of key human interest through the centuries, with a central role played by sal ammoniac in alchemy and the emergence of modern science. The review highlights how recent environmental research has emphasized volatilization sources of ammonia. Conversely, the historical records emphasize the role of high-temperature sources, including dung burning, coal burning, naturally burning coal seams and volcanoes. Present estimates of ammonia emissions from these sources are based on few measurements, which should be a future priority.     

Environmental innovation activities and patenting: Germany reconsidered

This paper provides new econometric evidence on the determinants of eco-innovations by using multiple innovation indicators and by combining survey-based information and patent records at the firm level from two different time periods. We hypothesize that firms with a propensity to patent focus on future technological and market opportunities and do not directly or immediately react to incentives created by environmental policies. Based on negative binomial models, we confirm that eco-patents are stimulated by the expectation of creating technological advancement and new market opportunities. By contrast, energy cost savings can better or more easily be achieved when firms refrain from patenting and concentrate on non-patented innovations or adoption. Favorable framework conditions created by environmental policies and patent protection are also important for eco-patenting, but more in the longer term. Testing the validity of using self-reported eco-innovations, instead of patents, as the dependent variable in simple binomial probit models reveals that product eco-innovations as reported in the surveys are a relatively good proxy for eco-patents. Yet, for product eco-innovations, serving and enlarging current markets is another important reason to innovate.     

Analysing the influence of different street vegetation on traffic-induced particle dispersion using microscale simulations

Urban vegetation can be viewed as compensation to the environmental drawbacks of urbanisation. However, its ecosystem function is not well-known and, for urban planning, vegetation is mainly considered as an element of urban design. This article argues that planning practice needs to re-examine the impact of vegetation cover in the urban fabric given our evaluation of vegetation's effects on air quality, including the dispersion of traffic-induced particles at street level. Using the three-dimensional microclimate model ENVI-met?, we evaluate these effects regarding the height-to-width ratio of streets flanked by buildings and the vertical and horizontal density of street vegetation. Our results reveal vegetation's effect on particle dispersion through its influence on street ventilation. In general, vegetation was found to reduce wind speed, causing inhibition of canyon ventilation and, consequently, an increase in particle concentrations. Vegetation was also found to reduce wind speed at crown-height and to disrupt the flow field in close vicinity to the canopy. With increasing height-to-width ratio of street canyons, wind speed reduction increases and the disturbance of the flow impacts across a canyon's entire width. We also found that the effect is more pronounced in configurations with poor ventilation, such as the low wind speed, perpendicular inflow direction, and in deep canyons cases.     

Dynamic Calibration of an Acid Aerosol Analyzer

A method is described for dynamic calibration of an acid aerosol analyzer based on a commercial modification of the Thomas Autometer and manufactured by the Instrument Development Company. This automated instrument removes acid aerosol from an air stream by sonic impaction, and the sulfuric acid collected is determined conductometrically. An all-glass aerosol generator based on the reaction of water vapor with sulfur trioxide vapor released from fuming sulfuric acid was built for the calibration. Air samples were withdrawn for instrument calibration before and after the concentration of the acid aerosol was determined by titration. The apparent particle size as determined by an Andersen sampler ranged from 2.0 microns to less than 0.68 micron and exhibited a sharp peak with mass median diameter at 1.3 microns in the distribution curve. The size of the aerosol, within certain limits, could be controlled by humidity. Data indicated a linear response with an aerosol collection efficiency of 80 percent in the important respirable size range.     

Distribution of Light Hydrocarbons in Ambient Air

The diversity of hydrocarbons which are present in ambient polluted air provide a potentially rich source of information concerning the nature of this type of pollution. Measurements of the relative amounts of various hydrocarbons can be correlated with the various possible sources. Since hydrocarbon reactivities vary widely it is also possible to estimate the extent to which various individual hydrocarbons have reacted. Except for samples taken deliberately near sources of hydrocarbon pollution these air samples invariably resemble auto exhaust with an addition of natural gas and of C₃–C₅ paraffins which resemble gasoline vapor. Samples taken in industrial areas and near the smoke plume from a brush fire showed distinctive differences in composition. During the smog season in the fall of 1968 good data were obtained of “typical” or “representative” samples of light, medium and heavy smog. These show the expected depletion of more reactive hydrocarbons in a much more convincing way than before. By comparing these distributions with composition in unreacted samples and by making use of data from bottle irradiations, it was possible to estimate the contribution of the various hydrocarbons in terms of “amount reacted.” The amounts of higher hydrocarbons present and reacted were also estimated from gasoline composition.     

Air Pollution Controls at Braintree Incinerator

A new incineration plant has replaced the sanitary landfill in Braintree, Mass. Designed in 1966 and completed in 1971 it includes sophisticated air pollution controls although existing laws or codes did not require them. The results of dust loading tests conducted by an independent organization are presented.     

Particle Size Distributions of Kraft Paper Mill Aerosols Obtained by Airborne Sampling

Size distributions of particles at several downwind points in a Kraft paper mill plume have been determined by means of airborne sampling. Size distributions from samples close to the stack were found to have a log normal frequency distribution, but significant deviations from the log normal were found farther downwind. Several possible physical mechanisms are postulated as causes for this behavior. Plume dilution with background particles appears to be the most likely mechanism. The airborne sampling system is described, and electron micrographs of sampled particles are presented.     

A Quality Assurance Management Plan

California Air Resources Board (CARB) staff developed a phased integrated approach to implement the Standing Air Monitoring Work Group’s (SAMWG) quality assurance requirements. This approach separates quality assurance requirements into a single project with a management plan and manager, and assigns each requirement to one of three key task areas—standardized methods and procedures measurement standards and tests, and audits. Tasks are assigned priorities and a detailed management plan is developed with SAMWG dates as milestones.

Benefits of the phased integrated approach are a streamlined, flexible quality assurance program; maximum utilization of personnel and resources; timely implementation of SAMWG requirements; a uniform quality assurance program applied to state, local, and private industry monitoring programs; and data with documented precision and accuracy. Additionally, peculiarities of procedures and analyzers that lead to data inaccuracies are quickly identified and corrected.