BACKGROUND: @entity7459 ( @entity6836 ) and @entity9733 ( @entity9734 ) generated by excessive coal combustion and motor vehicle emissions are major air pollutants in the large cities of China. The objective of our study was to determine the effects of the exposure of oak pollens (Quercusmongolica) to several concentrations of @entity6836 or @entity9734 . METHODS: Pollen grains were exposed to 0.5 ppm to 5.0 ppm @entity6836 or @entity9734 for 4 hours and assessed for morphological damage by field emission scanning electron microscopy and for viability using the @entity3460 stain. Morphological changes in pollen grains were also examined after contact with acid solutions at pH 4.0 to pH 7.0. RESULTS: Exposure to @entity6836 or @entity9734 significantly damaged pollen grains at all concentrations investigated, compared to exposure to air; with exposure to concentrations of 0.5 ppm to 2 ppm resulting in fissures or complete breaks in the exine and a concentration of 5 ppm resulting in complete breakdown and release of pollen cytoplasmic granules. Significantly greater amounts of pollen grain were damaged after exposure to @entity9734 (15.5-20.4%) than after exposure to @entity6836 (7.1-14.7%). Similarly, exposure to @entity6836 or @entity9734 significantly decreased the viability of pollen grains, compared with exposure to air; with @entity9734 being slightly more detrimental than @entity6836 . Exposure to acid solutions also induced @entity16 , which appeared to be pH-dependent (from 24.6% at pH 6.0 to 55.8% at pH 4.0; compared to 3.8% at pH 7.0). CONCLUSION: Short-term exposure of oak pollen to high concentrations of @entity9734 or @entity6836 significantly increases their fragility and disruption, leading to subsequent release of pollen cytoplasmic granules into the atmosphere. These results suggest that heightened air pollution during the oak pollen season may possibly increase the incidence of @entity56 in sensitized individuals by facilitating the bioavailability of airborne pollen allergens.

Effect of @entity7459 and XXXX on viability and morphology of oak pollen.

@entity7459 :: ('MESH:D009585', 'Chemical') :: ['Nitrogen dioxide'] @entity16 :: ('MESH:D009422', 'Disease') :: ['pollen damage'] @entity9733 :: ('MESH:D013458', 'Chemical') :: ['sulfur dioxide'] @entity3460 :: ('MESH:D014343', 'Chemical') :: ['trypan blue'] @entity6836 :: ('CHEBI:29785', 'Chemical') :: ['NO2'] @entity56 :: ('MESH:D004342', 'Disease') :: ['allergic airway disease'] @entity9734 :: ('CHEBI:29825', 'Chemical') :: ['SO2']
@entity9733 :: (MESH:D013458,Chemical) :: ['sulfur dioxide']
