Concentrations of gaseous and particulate air pollutants, and deposition fluxes of NO−3, SO2−4, and NH+4 ions to branches of California lilac (Ceanothus crassifolius Torr.), Coulter pine (Pinus coulteri D. Don.), ponderosa pine (P. ponderosa Dongl. ex P. & C. Lawson), nylon filters, and paper filters were measured in open-top field chambers with different filtration materials and in chamberless outside plots. Concentrations of O3 inside charcoal-filtered (CHARCOAL) chambers were reduced to 18 to 24% of the outside concentrations, while concentrations of NO2 were reduced to about 42 to 67%, with a simultaneous increase of NO concentrations. Concentrations of these gases in the chambers equipped only with the fiberglass dust filter (DUST 1) and fiberglass dust filter plus heavy duty strainer mat (DUST 2) were similar to those in the outside plots. On the average, concentrations of NO−3 (sum of particulate nitrate and nitric acid vapor) in the CHARCOAL chambers were reduced to about 40% of the outside levels, while concentrations of particulate SO2−4 and NH+4 (sum of particulate NH+4 and NH3) were reduced to about 84 and 79%, respectively. In the DUST 1 and DUST 2 chambers, concentrations of NO−3 were reduced to about 73% of the outside levels, and concentrations of SO2−4 and NH+4 to about 90 and 92%, respectively. Effects of different air filtrations were more evident for deposition fluxes to plant and surrogate surfaces. On the average, in the CHARCOAL chambers, deposition fluxes of NO−3, SO2−4, and NH+4 to the surfaces were reduced to 21, 38, and 26% of the outside values, respectively. In the DUST 1 and DUST 2 chambers, deposition fluxes of NO−3, SO2−4, and NH+4 were reduced to about 50, 56, and 75% of the outside levels, respectively. Deposition fluxes of the studied ions to plants were much lower than to nylon and paper filters. The results of this study add important information for open-top chamber studies, especially if long-term effects of ambient concentrations of air pollutants on vegetation are considered.
Research supported in part by the Southern California Edison Company under Contract no. 487610-59292. Mention of a product does not constitute a guarantee or warranty by the Univ. of California or the Southern California Edison Company, and does not imply endorsement of it to the exclusion of other products.