Crop loss due to air pollution in The Netherlands

The extent of yield reduction and economic loss caused by air pollution has been estimated for The Netherlands. Based on available data on direct effects only, each species was designated as sensitive, moderately sensitive or tolerant. On a nationwide scale, only ozone (O3), sulphur dioxide (SO2), and hydrogen fluoride (HF) exceeded effect thresholds. Effects from pollutant combinations were assumed to be additive. Yield reductions were calculated, using 10 exposure-response relationships and concentration data from the Dutch air pollution monitoring network. Changes in air pollution levels result in changes in supply. By multiplying the supply with the current price, the so-called crop volume was calculated. Subsequently, changes in crop volume were converted into economic terms, taking into account demand elasticity. On the basis of these calculations, air pollution in The Netherlands reduces total crop volume by 5%:3.4% by O3, 1.2% by SO2, and 0.4% by HF. The slope of the nonlinear relationship between crop volume reduction and exposure level increases at higher concentrations. In general, air pollution causes relatively little loss to producers, since yield reductions are largely compensated by higher prices. If air pollution in The Netherlands would be reduced to background concentrations, consumers would experience a net gain of Dfl 640 million (US 320 million dollars). Although large amounts of data were attained through literature and our own experience for this study, many assumptions still had to be made to arrive at these conclusions. With the current available knowledge, validation of our results in the field is not yet possible.     

Source contributions to carbonaceous aerosols in the Tennessee Valley Region

Sources of carbonaceous aerosols collected from three sites of Chattanooga, TN (CH), Muscle Shoals, AL (MS), and Look Rock, TN (LR) in the Tennessee Valley Region (TVR) were apportioned using both organic tracer-based chemical mass balance (CMB) modeling and radiocarbon (¹⁴C) measurement and the results were compared. Eight sources were resolved by CMB, among which wood combustion (averaging 0.92 μg m⁻³) was the largest contributor to primary organic carbon (OC) concentrations, followed by gasoline exhaust (0.35 μg m⁻³), and diesel exhaust (0.18 μg m⁻³). The identified primary sources accounted for 43%, 71%, and 14% of measured OC at CH, MS, and LR, respectively. Contributions from the eight primary sources resolved by CMB could explain 107±10% of ambient elemental carbon (EC) concentrations, with diesel exhaust (66±32%) and wood combustion (37±33%) as the most important contributors. The fossil fractions in total carbon determined by ¹⁴C measurements were in reasonably good agreement with that in primary (OC+EC) carbon apportioned by CMB in the MS winter samples. The comparison between the ¹⁴C and CMB results revealed that contemporary sources dominated other OC in the TVR, especially in summertime (84% contemporary).     

Chemical composition of fine particles in the Tennessee Valley region

Fine particles in the atmosphere have elicited new national ambient air quality standards (NAAQS) because of their potential role in health effects and visibility-reducing haze. Since April 1997, Tennessee Valley Authority (TVA) has measured fine particles (PM2.5) in the Tennessee Valley region using prototype Federal Reference Method (FRM) samplers, and results indicate that the new NAAQS annual standard will be difficult to meet in this region. The composition of many of these fine particle samples has been determined using analytical methods for elements, soluble ions, and organic and elemental carbon. The results indicate that about one-third of the measured mass is SO4(-2), one-third is organic aerosol, and the remainder is other materials. The fraction of SO4(-2) is highest at rural sites and during summer conditions, with greater proportions of organic aerosol in urban areas throughout the year. Additional measurements of fine particle mass and composition have been made to obtain the short-term variability of fine mass as it pertains to human exposure. Measurements to account for semi-volatile constituents of fine mass (nitrates, semi-volatile organics) indicate that the FRM may significantly under-measure organic constituents. The potentially controllable anthropogenic fraction of organic aerosols is still largely unknown.     

Chemical Composition of Fine Particles in the Tennessee Valley Region

ABSTRACT

Fine particles in the atmosphere have elicited new national ambient air quality standards (NAAQS) because of their potential role in health effects and visibility-reducing haze. Since April 1997, Tennessee Valley Authority (TVA) has measured fine particles (PM_2.5) in the Tennessee Valley region using prototype Federal Reference Method (FRM) samplers, and results indicate that the new NAAQS annual standard will be difficult to meet in this region. The composition of many of these fine particle samples has been determined using analytical methods for elements, soluble ions, and organic and elemental carbon. The results indicate that about one-third of the measured mass is SO₄ ^-2, one-third is organic aerosol, and the remainder is other materials. The fraction of SO₄ ^-2 is highest at rural sites and during summer conditions, with greater proportions of organic aerosol in urban areas throughout the year. Additional measurements of fine particle mass and composition have been made to obtain the short-term variability of fine mass as it pertains to human exposure. Measurements to account for semi-volatile constituents of fine mass (nitrates, semi-volatile organics) indicate that the FRM may significantly under-measure organic constituents. The potentially controllable anthropogenic fraction of organic aerosols is still largely unknown.     

Crop loss assessment for California: modeling losses with different ozone standard scenarios

Crop yield losses were estimated for ambient O3 concentrations and for a series of potential O3 air quality standards for California, including the current statewide 1-h oxidant (O3) standard of 0.10 ppm (196 microg m(-3)), 12-h growing season averages, and other models. A model for statewide losses was developed using hourly O3 data for all sites in the State, county crop productivity data, and available O3 concentration-yield loss equations to determine potential yield losses for each crop in each county in California for 1984. Losses were based on comparison to an estimated background filtered air concentration of 0.025 or 0.027 ppm, for 12 or 7 h, respectively. Potential losses due to ambient air in 1984 were estimated at 19% to 25% for dry beans, cotton, grapes, lemons, onions, and oranges. Losses of 5% to 9% were estimated for alfalfa and sweet corn. Losses of 4% or less were estimated for barley, field corn, lettuce, grain sorghum, rice, corn silage, spinach, strawberries, sugar beets, fresh tomatoes, processing tomatoes, and wheat. Implementation of either a modified rollback to meet the current 1 h California O3 standard (0.10 ppm) or a three-month, 12-h growing season average of 0.045 ppm was necessary to produce large reductions in potential crop losses.     

Black cherry growth response to ambient ozone and EDU

Field-grown black cherry (Prunus serotina Ehrh.) seedlings were treated with the antioxidant ethylenediurea (EDU) to evaluate height, diameter, and above-ground dry-weight biomass growth response to ambient ozone over four years. Nine blocks with 44 trees/block were used in a randomized complete block design with three foliar spray treatments: (1) 1000 ppm EDU mixed with a surfactant and water; (2) surfactant mixed with water; and (3) water only. In each growing season treatments were applied seven times at approximately 10-day intervals. Repeated measures analysis of variance indicated significant (P< or =0.05) treatment and year effects for log-transformed height and diameter growth over the four-year period. After four years, EDU-treated trees were approximately 17% taller and stem diameters were 21% greater than non-EDU-treated trees. Total above-ground dry-weight biomass at the end of four years was 47% greater for EDU-treated trees compared to non-EDU-treated trees.     

Future impacts of distributed power generation on ambient ozone and particulate matter concentrations in the San Joaquin Valley of California

Distributed power generation-electricity generation that is produced by many small stationary power generators distributed throughout an urban air basin-has the potential to supply a significant portion of electricity in future years. As a result, distributed generation may lead to increased pollutant emissions within an urban air basin, which could adversely affect air quality. However, the use of combined heating and power with distributed generation may reduce the energy consumption for space heating and air conditioning, resulting in a net decrease of pollutant and greenhouse gas emissions. This work used a systematic approach based on land-use geographical information system data to determine the spatial and temporal distribution of distributed generation emissions in the San Joaquin Valley Air Basin of California and simulated the potential air quality impacts using state-of-the-art three-dimensional computer models. The evaluation of the potential market penetration of distributed generation focuses on the year 2023. In general, the air quality impacts of distributed generation were found to be small due to the restrictive 2007 California Air Resources Board air emission standards applied to all distributed generation units and due to the use of combined heating and power. Results suggest that if distributed generation units were allowed to emit at the current Best Available Control Technology standards (which are less restrictive than the 2007 California Air Resources Board standards), air quality impacts of distributed generation could compromise compliance with the federal 8-hr average ozone standard in the region.     

Variation of ozone concentrations in the ambient air of Baghdad

Measurements of ozone concentration in the ambient air of the city of Baghdad were carried out for the period October 1983 to October 1984. The O₃, probably of local origin, showed a typical diurnal and seasonal variation. Maximum daily 1-h O₃ concentrations higher than the international ambient air quality standards were observed regularly during the summer months. High O₃ concentrations during the night were also observed. Scatter diagrams were used to relate the O₃ concentrations with temperature, solar radiation and humidity.     

Detecting plant effects is necessary to give biological significance to ambient ozone monitoring data and predictive ozone standards

The use of mechanical monitors and passive samplers has made it possible to assess concentrations of ozone over wide areas and to develop air quality standards, like AOT40 and SUM60. Monitored ozone data and AOT40 and SUM60 are also used to predict ozone injury on local and regional scales. The data and the standards do not include or account for environmental and biological variables that affect ozone uptake and plant injury. Ground proofing via vegetation surveys must be done to verify and validate plant injury predictions. If this is not done, then the standards have no biological significance and are only exercises in air quality assessment.     

Analysis of ozone in the San Joaquin Valley of California

The dynamics of ozone in the San Joaquin Valley of central California are studied by systematic diagnostic runs of the three-dimensional SARMAP Air Quality Model. Air quality in the San Joaquin Valley is the result of a complex combination of local and transported emissions. Simulations show that relatively brisk winds at points of inflow to the Valley produce a strong dependence of ozone in the Valley on upwind conditions. Furthermore, NO_x influx from boundaries and local emissions has significantly greater impact on ozone production than ROG influx and emissions.     

Instrumental recording and biomonitoring of ambient ozone in the Greek countryside

Among eight commercial Greek varieties of tobacco (Nicotiana tabacum L.) tested for their ozone-sensitivity levels, the Zichnomirodata (KK6/5) variety was found to be the most sensitive, although less sensitive than the well-known super-sensitive Bel-W3. Besides qualitative differences in the appearance of macroscopic symptoms these two varieties can be used simultaneously as a reliable pair of ozone bioindicators. The occurrence of ozone in the Greek countryside was surveyed by biomonitoring in 14 rural regions over the country and by a simultaneous biomonitoring and instrumental recording of ozone concentrations at a single remote side (Pournaria, Arcadia). Phytotoxic symptoms were observed mainly on the leaves of Bel-W3 and occasionally on those of Zichnomirodata varieties, suggesting that ozone levels were high enough to affect at least sensitive species. The instrumental monitoring (during a total period of 912 h) revealed maximum hourly O3 concentration 62 ppb, while the thresholds of 30, 40 and 50 ppb were exceeded for 40%, 20% and 6% of the recording period, respectively. The accumulated exposure over 40 ppb (AOT40) for the daylight hours over the 38 monitored days was 680 ppb h.     

Improved ambient air quality due to lead in petrol regulation

The enforcement of the Petrol Lead Law by limiting the maximum lead concentration in petrol from 0.40 g/1 to 0.15 g/1 effective January 1, 1976, led to a decrease of the total lead emission of about 45% in the Federal Republic of Germany.The reduction of the lead concentration in the ambient air is strongly influenced by the motor traffic.The observed, decrease ranges between 65% (main roads, city centers) and 20% (areas under influence of industrial emissions, low traffic).     

Increase in summer European ozone amounts due to climate change

The local and regional distribution of pollutants is significantly influenced by weather patterns and variability along with the spatial patterns of emissions. Therefore, climatic changes which affect local meteorological conditions can alter air quality. We use the regional air quality model CHIMERE driven by meteorological fields from regional climate change simulations to investigate changes in summer ozone mixing ratios over Europe under increased greenhouse gas (GHG) forcing. Using three 30-year simulation periods, we find that daily peak ozone amounts as well as average ozone concentrations substantially increase during summer in future climate conditions. This is mostly due to higher temperatures and reduced cloudiness and precipitation over Europe and it leads to a higher number of ozone events exceeding information and warning thresholds. Our results show a pronounced regional variability, with the largest effects of climate change on ozone concentrations occurring over England, Belgium, Germany and France. The temperature-driven increase in biogenic emissions appears to enhance the ozone production and isoprene was identified as the most important chemical factor in the ozone sensitivity. We also find that summer ozone levels in future climate projections are similar to those found during the exceptionally warm and dry European summer of 2003. Our simulations suggest that in future climate conditions summer ozone might pose a much more serious threat to human health, agriculture and natural ecosystems in Europe, so that the effects of climate trends on pollutant amounts should be considered in future emission control measures.     

The use of ambient data to corroborate analyses of ozone control strategies

Data from environmental-chamber studies and photochemical box-model simulations were used to evaluate and revise a method for developing a qualitative understanding of the sensitivity of ozone formation at a particular time and place to changes in concentrations of volatile organic compounds (VOC) and oxides of nitrogen (NO_x). The revised method requires measurements of ozone, NO, and either NO_x or NO_y. The sensitivities of the method to biases in measurements were evaluated. The method potentially can be used for qualitative assessment of VOC versus NO_x limitation, comparison with the predictions of grid-based photochemical air-quality models, and evaluation of trends over time in the relative effectiveness of VOC versus NO_x controls.     

Outdoor/Indoor/Personal ozone exposures of children in Nashville, Tennessee

An ozone (O3) exposure study was conducted in Nashville, TN, using passive O3 samplers to measure six weekly outdoor, indoor, and personal O3 exposure estimates for a group of 10- to 12-yr-old elementary school children. Thirty-six children from two Nashville area communities (Inglewood and Hendersonville) participated in the O3 sampling program, and 99 children provided additional time-activity information by telephone interview. By design, this study coincided with the 1994 Nashville/Middle Tennessee Ozone Study conducted by the Southern Oxidants Study, which provided enhanced continuous ambient O3 monitoring across the Nashville area. Passive sampling estimated weekly average outdoor O3 concentrations from 0.011 to 0.O30 ppm in the urban Inglewood community and from 0.015 to 0.042 ppm in suburban Hendersonville. The maximum 1- and 8-hr ambient concentrations encountered at the Hendersonville continuous monitor exceeded the levels of the 1- and 8-hr metrics for the O3 National Ambient Air Quality Standard. Weekly average personal O3 exposures ranged from 0.0013 to 0.0064 ppm (7-31% of outdoor levels). Personal O3 exposures reflected the proportional amount of time spent in indoor and outdoor environments. Air-conditioned homes displayed very low indoor O3 concentrations, and homes using open windows and fans for ventilation displayed much higher concentrations.     

Assessing plant response to ambient ozone: growth of young apple trees in open-top chambers and corresponding ambient air plots

Open-top chambers (OTCs) and corresponding ambient air plots (AA) were used to assess the impact of ambient ozone on growth of newly planted apple trees at the Montague Field research center in Amherst, MA. Two-year-old apple trees (Malus domestica Borkh 'Rogers Red McIntosh') were planted in the ground in circular plots. Four of the plots were enclosed with OTCs where incoming air was charcoal-filtered (CF); four were enclosed with OTCs where incoming air was not charcoal-filtered (NF) and four were not enclosed, allowing access to ambient air conditions (AA). Conditions in both CF and NF OTCs resulted in increased tree growth and changed incidence of disease and arthropod pests, compared to trees in AA. As a result, we were not able to use the OTC method to assess the impact of ambient ozone on growth of young apple trees in Amherst, MA.     

Bioindicator plants for ambient ozone in Central and Eastern Europe

Sixteen species of native detector plants for ambient ozone have been identified for use in Central and Eastern Europe. They include the forbs Alchemilla sp., Astrantia major, Centuarea nigra, Centauria scabiosa, Impatiens parviflora, Lapsana communis, Rumex acetosa and Senecio subalpinus; the shrubs Corylus avellana, Cornus sanguinea and Sambucus racemosa; the trees Alnus incana, Pinus cembra and Sorbus aucuparia; and the vines Humulus lupulus and Parthenocissus quinquefolia. Sensitivity to ozone and symptoms have been verified under controlled exposure conditions. Under these conditions, symptom incidence, intensity and appearance often changed with time after removal from exposure chambers. Ozone sensitivity for four species: Astrantia major, Centuarea nigra, C. scabiosa and Humulus lupulus are reported here for the first time. The other 12 species have also been confirmed by others in Western Europe. It is recommended that these detector bioindicator species be used in conjunction with ozone monitors and passive samplers so that injury symptoms incidence can be used to give biological significance to monitored ambient ozone data.     

Prediction of ozone concentration in ambient air using multivariate methods

Multivariate statistical methods including pattern recognition (Principal Component Analysis--PCA) and modeling (Multiple Linear Regression--MLR, Partial Least Squares--PLS, as well as Principal Component Regression--PCR) methods were carried out to evaluate the state of ambient air in Miskolc (second largest city in Hungary). Samples were taken from near the ground at a place with an extremely heavy traffic. Although PCA is not able to determine the significance of variables, it can uncover their similarities and classify the cases. PCA revealed that it is worth to separate day and night data because different factors influence the ozone concentrations during all day. Ozone concentration was modeled by MLR and PCR with the same efficiency if the conditions of meteorological parameters were not changed (i.e. morning and afternoon). Without night data, PCR and PLS suggest that the main process is not a photochemical but a chemical one.     

Responses of field-grown Medicago sativa L. to acidic fog and ambient ozone

The relationship between pollutant-induced leaf drop or reductions in foliar pigment concentrations and yield was determined for field-grown alfalfa (Medicago sativa L. 'Moapa') exposed to simulated fogs of pH 7.24, 2.69 and 1.68 singly, and in combination with ambient ozone (O3) over an 11-week period. Highly acidic fog (pH 1.68) or ambient O3 significantly reduced totalseason dry yield and foliar pigment concentrations, and increased leaf drop. Significant interactive effects between acidic fog and O3 were observed for the leaf parameters, but not for yield. Thus, multiple exposures to acidic fog at current ambient levels of acidity (i.e. pH 2.69) could effect leaf quality in the absence of significant effects on yield. Alternatively, O3-induced effects on leaves may have utility as bioindicators of potential yield losses.