The Effect of Air Pollution on Yield and Quality of Mung Bean Grown in Peri-Urban Areas of Varanasi

There is growing concern that air pollution may have adverse impacts on crops in developing countries, yet this has been little studied. This paper addresses this issue, for a major leguminous crop of the Indian sub continent, examining the effect of air pollution in and around an Indian city. A field study was conducted using a gradient approach to elucidate the impact of air pollutants on selected production characteristics of Vigna radiata L. cv. Malviya Jyoti (mung bean) plants grown from germination to maturity at locations with differing concentrations of air pollutants around peri-urban and rural areas of Varanasi. The 6 -h daily mean SO₂, NO₂ and O₃ concentrations varied from 8.05 to 32.2 ppb, 11.7 to 80.1 ppb and 9.7 to 58.5 ppb, respectively, between the sites. Microclimatic conditions did not vary significantly between the sites. Changes in plant performance at different sites were evaluated with reference to ambient air quality status. Reductions in biomass accumulation and seed yields were highest at the site experiencing highest concentrations of all three gaseous pollutants. The magnitude of response indicated that at peri-urban sites SO₂, NO₂ and O₃ were all contributing to these effects, whereas at rural sites NO₂ and O₃ combinations appeared to have more influence. The quality of seed was also found to be negatively influenced by the ambient levels of pollutants. It is concluded that the air pollution regime of Varanasi City causes a major threat to mung bean plants, both in terms of yield and crop quality, with serious implications for the nutrition of the urban poor.     

A modified nitrogen oxide-ozone photolytic cycle

Nitrogen Oxide-0₃ photolytic cycle is dependent upon the presence of NO in ambient air. From our air monitoring observations we have found that the NO concentration in the atmosphere is often zero (0 to 5 ppb). This suggests a need to modify/change the photolytic cycle. Linear regression analyses on the O₃ and NO₂ concentrations in ambient air, measured in real time were carried out. The predicted values of O₃ and NO₂ from these regression equations were close to the observed values. On the basis of these two observations a modified photolytic cycle, including some other components (such as HONO₂) is discussed.     

The relative effectiveness of NOx and VOC strategies in reducing Northeast U.S. ozone concentrations

This investigation was conducted to compare the relative benefits of controlling emissions of VOC vs. NO_x for reducing tropospheric O₃ (smog) concentrations in the Northeast United States. Because of the nonlinear nature of O₃ photochemistry, controls on NO_x emissions could actually result in increases in O₃ depending on the relative amount of VOC present and meteorological conditions. The Regional Oxidant Model (ROM) was used as the tool for estimating the impacts of different VOC and NO₃ strategies. Scenarios simulated include a future baseline and separate strategies with controls on just NO, just VOC, and a combination of VOC and NO_x controls. The results indicate that in general, NO_x controls are more beneficial across the region than VOC controls. However, for several large urban areas, NO_x controls were predicted to result in higher O₃ than VOC controls. Also, the relative benefits of VOC and NO_x controls varied from day-to-day suggesting a dependency on meteorological conditions. Given the variable nature of the effects of NO_x controls, additional modeling using more spatially resolved models is warranted to identify specific strategies for attainment of the ozone NAAQS in individual areas.     

Physiological Effects of Exposure to Arsenic,Mercury, Antimony and Selenium in the Aquatic Moss Fontinalis antipyretica Hedw.

This study assessed the effect of ambient air pollution on leaf characteristics of white willow, northern red oak, and Scots pine. Willow, oak, and pine saplings were planted at sixteen locations in Belgium, where nitrogen dioxide (NO₂), ozone (O₃), sulfur dioxide (SO₂), and particulate matter (PM₁₀) concentrations were continuously measured. The trees were exposed to ambient air during 6 months (April–September 2010), and, thereafter, specific leaf area (SLA), stomatal resistance (R _s), leaf fluctuating asymmetry (FA), drop contact angle (CA), relative chlorophyll content, and chlorophyll fluorescence (F _v/F _m) were measured. Leaf characteristics of willow, oak, and pine were differently related to the ambient air pollution, indicating a species-dependent response. Willow and pine had a higher SLA at measuring stations with higher NO₂ and lower O₃ concentrations. Willow had a higher R _s and pine had a higher F _v/F _m at measuring stations with a higher NO₂ and lower O₃ concentrations, while oak had a higher F _v/F _m and a lower FA at measuring stations with a higher NO₂ and lower O₃ concentrations. FA and R _s of willow, oak, and pine, SLA of oak, and CA of willow were rather an indicator for local adaptation to the micro-environment than an indicator for the ambient air pollution.     

Estimate of health impacts of acidifying air pollutants and tropospheric ozone in Europe

Based on combined information available from air quality monitoring data and long-range transport models, European population exposure to SO₂, NO₂ and O₃ has been estimated. This information has been combined with the results of epidemiological studies assessing strength of association between the exposure and health effects to estimate an impact of the pollution on health in Europe. The analysis indicates that a considerable number of health problems, ranging from mild irritation of the respiratory system to increased mortality, can be attributed to short-term peaks of pollution observed in Europe. Chronic impacts of prolonged elevated SO₂ levels on lung function are estimated to occur in close to10 million people in Europe.     

Effects of air pollution on the searching behaviour of an insect parasitoid

To assess the impact of air pollutants on the population dynamics of herbivores, the effects of pollutants on their natural enemies including predators, parasites, and pathogens must be evaluated in addition to direct effects and indirect effects mediated via the host plant. Insect parasitoids are an important group of such natural enemies providing many examples of partial or complete biological control of pest species. This study examined the effects of air pollutants (ozone (O₃), sulphur dioxide (SO₂), and nitrogen dioxide (NO₂)) on the searching behaviour of insect parasitoids. A series of experiments comprising short-term, closed chamber fumigations of O₃, SO₂, and NO₂ (100 nl l^?1) of the braconid parasitoid (Asobara tabida) and aggregated distributions of its host larvae (Drosophila subobscura) was set up. Analysis of chamber results showed that the proportion of hosts parasitised and the searching efficiency of the parasitoids were both significantly reduced with O₃ fumigation, but not with NO₂ or SO₂ fumigations. O₃ fumigation reduced percentage parasitism by approximately 10%. Parasitoids were able to avoid patches with no hosts, both in filtered air controls and when exposed to pollutants. However in the O₃ and NO₂ treatments they appeared less able to discriminate between different host densities, suggesting that pollutants may interfere with the olfactory responses of the parasitoids. These results indicate the potential for air pollutants, particularly O₃, to negatively influence the searching behaviour of parasitoids, and hence reduce the efficiency of natural enemy control of many pest species.     

A Study of PM2.5 and PM2.5-Associated Polycyclic Aromatic Hydrocarbons at an Urban Site in the Po Valley (Bologna, Italy)

PM_2.5 and PAHs bound to PM_2.5 were investigated in downtown Bologna, from January to June 2003, in order to determine the burden of the fine fraction in the aerosol of a typical urban environment of the Po Valley, a critical area in Northern Italy in terms of atmospheric pollution. The sampling campaign was divided into three parts: a winter sub-campaign, an intermediate campaign where PM_2.5 and PM₁₀ were simultaneously sampled and which identified PM_2.5 as the major component of PM₁₀, and a summer sub-campaign. Critical concentrations of both PM_2.5 and PAHs were observed in winter time; for example, in January 2003 the mean value for the 24-h average PM_2.5 concentration was 58 μg/m³, much higher than the annual arithmetic mean of 15 μg/m³ established by the US ambient air quality standard (NAAQS). Correspondingly, the mean value for benzo[a]pyrene (BAP) in PM_2.5 was 1.79 ng/m³, again higher than the annual mean of 1 ng/m³, required by European regulations for BAP in PM₁₀. In summer time the BAP concentration considerably decreases to 0.10 ng/m³ as the likely effect of photolysis and dilution on a higher boundary layer; PM_2.5 decreases too, but the mean concentration (22 μg/m³) is still higher than the NAAQS value. Further analysis included TEM microscopy of collected particles and correlations between PM_2.5, PAHs and gases (benzene, O₃, CO, NO₂, SO₂). All these observations identified on-road mobile sources as the main source of emissions and, in general, of the poor air quality level in the city of Bologna.     

Trends of Air Pollution and Its Present Situation in Hiroshima Prefecture

The ambient concentration of SO₂, NOx and O_x in the atmosphere of Hiroshima, Fukuyama and Fuchu city which were monitored by the prefectural monitoring stations, are examined to give a picture of the typical air pollution at these sites. Results show that the yearly concentrations of SO₂ in these areas are significantly fall from 20 to 6 ppb during 1978–1996 when the NOx concentrations having no such significant change which varies from 40 to 30 ppb. The Photo-chemical Oxidant (Ox) increases annually at the rate of 0.3 ppb to 0.6 ppb in Hiroshima city only. To know the present situation of air pollution the Differential Optical Absorption Spectroscopy (DOAS) system is used in the city of Higashi Hiroshima. The daily average concentrations of SO₂, NO₂, O₃ and HONO measured during the period of August 1999 to March 2000 ranged from 1.4 ppb to 2.8 ppb, 13 ppb to 26.9 ppb, 21 ppb to 53.6 ppb and 1 ppb to 4.3 ppb respectively. The patterns of concentrations of NO₂ and O₃ measured by DOAS look similar to the seasonal patterns of NOx and Ox by the conventional system.     

Measurement needs for developing and assessing ozone-control strategies

The monitoring programs needed to design control strategies differ from those required to assess the impact of the strategies on air quality. The former are short-term and intensive. They are designed to obtain the data required to apply an urban-scale grid model, like the Urban Airshed Model, or a combination of an urban-scale and regional-scale model, like the Regional Oxidant Model, to an area without having to assume important input data. Such measurements include three-dimensional pollutant and meteorological measurements throughout the modeling domain. Detailed and accurate emissions inventories are also required. Model validation should compare not only the O₃ predictions with actual data, but also include comparisons for NO _x , individual volatile organic compounds (VOC), and if possible, additional species such as PAN, H₂O₂, formaldehyde, and HNO₃. To assess the impact of control strategies, long-term monitoring networks that measure O₃, NO _x and speciated VOC are needed. O₃ trends should be examined using robust, meteorologically-adjusted O₃ statistics. Such statistics need to be related to a robust National Ambient Air Quality Standard.     

Some measurements of air quality and precipitation in Saint John,N.B.

For the period of November 19 to 23, 1973, and July 13 to 23, 1974, air quality and precipitation measurements were made in and around Saint John, New Brunswick. For both periods it was found that SO₂ concentrations could be appreciable at several locations (with hourly maxima near 40 pphm). Sulfur dioxide fumigation from a power plant plume and H₂S concentrations near a Kraft process pulp and paper mill are discussed. For the July period, O₃, NO and NO₂ were measured in the background air as well as in air downwind of the city. The ambient concentrations were not unusually high, with the O₃ reaching levels up to 8 pphm (hourly average) on clear sunny days. Precipitation samples were collected on several occasions and the analyses indicate that concentrations of acid-forming species were not markedly different from those found in other Canadian cities.     

SO2 Transformation in controlled atmosphere leading to the production of aerosol particles

The photochemical transformation of SO₂ and the generation of aerosol particles are investigated in a variety of atmospheres, with and without initial aerosols, in clean and polluted air, and with various pollutants. The pollutants in addition to the SO₂ include O₃, NO, NO₂ and water vapor in a variety of combinations. The most striking finding is, that only with the combination of SO₂, NO₂, and H₂O is the aerosol particle production large.     

Impacts of Ambient Ozone and/or Acid Mist on the Growth of 14 Tree Species: An Open-Top Chamber Study Conducted in Japan

Young trees of 14 species were exposed to ambient ozone (O₃), (charcoal-filtered air [CF] or non-filtered air [NF]) and/or acid mist (pH 5 or 3: SO₄ ^2?, NO₃ ^?, Cl^? at equivalent 1:2:1 ratio) over three seasons (from June 1993 to November 1995) using tunnel-type open-top chambers at two sites (Abiko: 25 m a.s.l. and Akagi: 540 m a.s.l.) in Japan. Ambient, 12-hr (0600–1800) mean O₃ concentration for April–September during the period of experiment at Akagi (41 ppb) was 40 % higher than that at Abiko (30 ppb). The NF- and CF-chambers had 90 % and 30 % of ambient O₃, respectively. Significant decreases in biomass in the NF treatments were observed in Pinus densiflora, Larix k aempferi, Picea abies, Abies firma, Abies homolepis, Abies veitchii, Cryptomeria japonica, Populus maximowiczii, Betula platyphylla, Fagus crenata and Zelkova serrata as compared with the CF treatment. These results indicate that the current ambient level of O₃ in Japan is high enough to have adverse effects on the growth of all tree species examined, except Pinus thunbergii, Chamaecyparis obtusa and Quercus mongolica. Increasing acidity of mist caused no growth decreases in all tree species examined. However, the growth decreases by O₃ were greater at pH 3 mist treatment than at pH 5 mist treatment on Abies veitchii and Fagus. This suggested that the O₃ effect on tree growth can be exacerbated by the deposition of acid mist, possibly associated with nitrate.     

Global emissions and natural processes for removal of gaseous pollutants

This review briefly illustrates the state of the art in the recognition of the various sources and natural sinks of gaseous pollutants. The removal mechanisms include absorption by vegetation, soil, stone, and water bodies, precipitation scavenging, and chemical reactions within the atmosphere. The nature and magnitude of anthropogenic and natural emissions of the gases (H₂S, SO₂, N₂O, NO, NO₂, NH₃, CO, O₃, and hydrocarbons), along with their ambient background concentrations and information on their major sinks identified to date, are discussed.     

Improvements in Urban Air Quality: Case Studies from New York State, USA

Air quality levels vary over regions due to meteorological factors, proximity to sources, and local conditions (i.e., topography). The Northeast USA is subjected to pollution inputs from both local sources and those from the upwind Midwest USA that are transported by prevailing meteorological patterns. With the passage of the Clean Air Act in 1970 and the establishment of the National Ambient Air Quality Standards (NAAQS), national levels of air pollutants have declined significantly. Our study compared air quality time trends between five of the largest cities within New York State (Albany, Buffalo, New York City, Rochester, and Syracuse) and statewide means to national trends. Data were obtained from the NYS Department of Environmental Conservation (DEC) Bureau of Air Quality Surveillance for six criteria pollutants: carbon monoxide (CO), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), ozone (O₃), particulate matter (PM_2.5), and lead (Pb). Regional Kendall tests found significant downward trends for each pollutant statewide from 1980 to 2007, while trends by city varied by decade and pollutant. The evaluation of historical trends of pollution in industrialized nations is useful in showing recent air quality improvements and also in the understanding what can be the result in air pollutant controls in those developing nations currently experiencing high levels of pollution.     

Effects of gaseous air pollutants on secondary chemistry of Scots pine and norway spruce seedlings

Plant secondary compounds have an important role in defense responses against herbivores and pathogens. This study summarises published and some unpublished data from a series of fumigation experiments where Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) seedlings were exposed to different concentrations of gaseous air pollutants, ozone (O₃), sulphur dioxide (SO₂) or nitrogen dioxide (NO₂), in growth chambers. Concentrations of monoterpenes, resin acids and total phenolics were studied. Overall, needle monoterpenes were not affected by pollutants. Only very high level of O₃ (600 ppb) decreased concentration of some individual monoterpenes in pine needles. O₃ did not have effect on concentrations of resin acids in pine needles. In contrast, the concentration of some individual resin acids increased in O₃-exposed pine shoots and in O₃-exposed needles of one spruce clone. The highest dose of SO₂ decreased concentrations of resin acids in pine needles, but low exposure levels did not have effects. However, SO₂ had no effects on the resin acids concentrations of spruce needles, except some minor individual compounds were affected in clonal spruces. Increased concentrations of resin acids was found in pine shoots exposed to NO₂. Total phenolics of needles were not affected by pollutants. These observations suggest that among secondary compounds there is variation in sensitivity to air pollutants and genetically different trees have different responses to air pollutants.     

Bush bean (Phaseolus vulgaris L) leaf injury,photosynthesis and stomatal functions under elevated ozone levels

Three bush bean cultivars (Lit, Groffy and Stella) were grown under four levels of ozone exposure (ambient air+50 ppb O₃ ambient air+25 ppb O₃, ambient air and charcoal filtered air) in open- top chambers. Number and leaf injury statistics showed significant reduction in the number of healthy leaves as the level of O₃ increased. The area based leaf injury percentages of the cvs. Lit, Groffy and Stella were 69.8, 57.9 and 71.1% at the highest O₃ level, 24.1, 19.6 and 30.3% at the 2nd highest O₃ level, and 4.5, 0.7 and 5.6% at the ambient air, respectively. The plants grown in the filtered air revealed no injury symptoms. The stomatal conductances were found to decrease gradually in each cultivar as the O₃ level increased. At the highest O₃ level, Chlorophyll fluorescence measurements on the 2nd leaf from the top on 24th day of exposure resulted in significantly the highest Fv/Fm values, the lowest f₀ and the highest F_m values whereas the 4th leaf showed the smallest Fm and correspondingly the smallest F_v/F_m values. This is an indication of photosystem II damage after accumulation of a high ozone dose in the 4th leaf. The photosynthetic rate of the 2nd leaf measured on 30th day of exposure was comparatively higher at the highest exposure but the data taken from the same leaf on 40th day of exposure showed significantly lower photosynthetic rate than the plants in ambient air. Both chlorophyll fluorescence and photosynthetic measurements indicated that ozone stressed leaves experience a stimulation of photosynthesis (possibly due to increased assimilate demand) prior to irreversible damage. Bush bean leaves need to accumulate a critical ozone dose(an AOT40 of presumably > 18 ppm-h) for reduction of the photosynthetic capacitys.     

Abstracts of Nippon Dojohiryogaku Zassui

The effects of NO₂ and O₃ exposure alone or in combination were investigated with respect to the amino acid content and composition in kidney bean. The short-term exposure (up to 8 h) to NO₂ at a concentration of 4.0 ppm alone or in combination with O₃ at a concentration of 0.4 ppm induced a rapid increase in the total amino acid content among which glutamine accounted for most of the part. Total amino acid content was also increased by O₃ exposure at 0.4 ppm after 2 hours’ lag period. Ammonium level became higher in the case of combined exposure to NO₂ and O₃, while it remained constant in the case of exposure to NO₂ and O₃ alone.

When the exposure period was extended to 2 to 7 days (long-term exposure), the increase in the content of the total amino acids was observed in most of treatments. Roots of the plants exposed to various concentrations of NO₂ and O₃ showed the most remarkable increase in the content of total amino acids. Asparagine, in place of glutamine, became a major amino acid. The percentage of asparagine was especially increased by the mixed exposure to NO₂ and O₃ These results indicate that glutamine which accumulates considerably in the early phase of the gas exposure (short-term exposure) seems to be gradually converted into other amino acids, mainly asparagine.

The correlation between the content of each amino acid, ammonium and total amino acids was calculated using data from the above experiment. Most of the amino acids in the primary and trifoliate leaves showed a high correlation with the total amino acids, suggesting that the changes in the amount of total amino acids caused by the air pollutants may be reflected not only by a particular amino acid, but also by an individual amino acid composing soluble metabolite pool. A high correlation was obtained among amino acids belonging to the serine family such as glYCine, serine, and cysteine.     

Effects of ambient air pollution on wheat and rice yield in Pakistan

Open-top chambers ventilated with ambient or chiarcoal-filtered air were used to assess the impact of air pollution on the yield of local cultivars of wheat and rice, at a site on the outskirts of Lahore. At this location, 6-h mean O₃ concentrations reach 60 ppb in certain months, and annual mean NO₂ concentrations are 20–25 ppb. The experiments showed significant yield reduction in two successive seasons which ranged from 33% to 46% in wheat and from 37% to 51% in rice. The major yield parameter affected was the number of ears or panicles per plant, although there was also evidence of small effects on 1000 grain weight and on the number of grains per ear/panicle. These results have significance in terms of the maintenance of agricultural yields as pollution emissions rise in south and south-east Asia.     

A mobile rain exclusion canopy system to determine dose-response relationships for crops and forest species

A fully automated rain exclusion canopy system has been designed and constructed to study the impact of simulated acid rain on the growth and yield of agricultural crops. The system consists of three, mobile greenhouse shelters which exclude ambient rainfall and apply simulated acid rain (SAR) treatments to crops established in field plots. All aspects of the field system are controlled by a microcomputer and data acquisition system. In addition, elevated ambient levels of gaseous pollutants (e.g. O₃, SO₂, NO_x) are reduced in field plots via an air exclusion system consisting of large blowers, potassium permanganate-treated alumina filters and perforated polyethylene tubes. Gaseous pollutants can be injected into the treatment plots via the blowers.     

Nitrogen oxides,regional transport,and ozone air quality: Results of a regional-scale model for the midwestern United States

An overview of the role of NO _x in the formation of rural O₃, regional transport and its potential impact on urban air quality is presented. An analysis of a specific O₃ excursion in southeast Michigan (8-2-90) is performed based on a combined urban and regional-scale model. The regional component of the model represents transport and photochemistry from sources as far away as Texas. Results suggest that rural O₃ and regional transport sensitive to NO _x emissions and relatively insensitive to changes in volatile organic carbon (VOC) emissions. This differs from the situation in urban areas, where O₃ is sensitive to both NO _x and VOC. Regional transport and upwind NO _x emissions have a significant impact on peak O₃ in Detroit. Implications for urban and regional-scale abatement strategies are discussed.