Gaseous and particulate reactive nitrogen species in the indoor air of selected households in New Delhi

Seasonal variations of dustfall fluxes and biochemical parameters in the foliage of selected indoor plants in Delhi, India

This study reports the seasonal variations in dry deposition of coarse and fine particles on the foliar surfaces of common indoor plants viz. Ficus elastica, Ficus lyrata, and Schefflera arboricola along with their biochemical changes in the urban households of metropolitan Delhi. The dustfall fluxes were significantly higher at the industrial site as compared to residential site and temporal variations indicated higher dustfall fluxes during the winter months as compared to other seasons. Seasonal concentrations of chlorophylls, pH, and soluble sugars were higher during monsoon season for the indoor plants whereas ascorbic acid content was higher in the winter season indicating more stress. The results of correlation plots revealed that the variations observed in the biochemical traits were interlinked with the changes in dustfall fluxes during different seasons, thereby reflecting the changes in air pollution stress faced by plant foliage. The air pollution tolerance index and anticipated performance index were evaluated to understand the overall tolerance of indoor plants toward air pollution which can be utilized in phytoremediation techniques. It was concluded that among the studied indoor plants, Ficus elastica and Ficus lyrata are better plant species than Schefflera arboricola for improving indoor air quality.

Abundance and variation of gaseous NH3 in relation with inorganic fertilizers and soil moisture during Kharif and Rabi season

In an agricultural country like India, inorganic fertilizers are the major contributors of atmospheric NH₃ in rural areas affecting soil, vegetation and water bodies. In this study, day-night and seasonal variation of ammonia emissions were measured from July 2017 to June 2018 during Kharif and Rabi crop seasons at a rural agricultural site in Jhajjar district of Haryana. Also, NH₃ emission inventory is prepared for the amount of fertilizers applied during its basal and top dressing. NH₃ concentrations were noticed significantly lower after basal dressing of DAP fertilizers as compared to the concentrations after top dressing of urea. NH₃ concentration in air increased with decrease in water saturation of the soil. NH₃ emission was recorded as 1.4 to 45.2, 63.1 to 190.9, and 98.9 to 187.5 μg m^-3 during sowing, fertilizer addition, and grain filling stages, respectively, in Kharif season. Apart from these crop stages, NH₃ was measured as 56.8 to 249.5 μg m^-3 during crop residue burning period. On the other hand, NH₃ emissions ranged from 22.9 to 68.4, 59.4 to 104.71, 26.3 to 56.0, 48.2 to 147.2, and 21.5 to 80.4 μg m^-3 during sowing, crown root initiation (CRI), panicle initiation, grain filling, and maturity crop, respectively, in Rabi season. The average NH₃ concentrations during Kharif season (125.3 μg m^-3) were significantly greater than the concentrations during Rabi season (51.8 μg m^-3). However, a reduction in the NH₃ values was observed in the period between Kharif and Rabi seasons, which could be attributed to the wet deposition during monsoon and gas to particle conversion due to less temperature conditions during the periods.

Particulate Matter, an Intrauterine Toxin Affecting Foetal Development and Beyond

Air pollution is the 9th cause of the overall disease burden globally. The solid component in the polluted air, particulate matters (PMs) with a diameter of 2.5 μm or smaller (PM_2.5) possess a significant health risk to several organ systems. PM_2.5 has also been shown to cross the blood–placental barrier and circulate in foetal blood. Therefore, it is considered an intrauterine environmental toxin. Exposure to PM_2.5 during the perinatal period, when the foetus is particularly susceptible to developmental defects, has been shown to reduce birth weight and cause preterm birth, with an increase in adult disease susceptibility in the offspring. However, few studies have thoroughly studied the health outcome of foetuses due to intrauterine exposure and the underlying mechanisms. This perspective summarises currently available evidence, which suggests that intrauterine exposure to PM_2.5 promotes oxidative stress and inflammation in a similar manner as occurs in response to direct PM exposure. Oxidative stress and inflammation are likely to be the common mechanisms underlying the dysfunction of multiple systems, offering potential targets for preventative strategies in pregnant mothers for an optimal foetal outcome.