Pyruvic acid and methane sulfonic acid, both products of photochemical reactions in air, are quantitated by ion chromatography analysis in borate and carbonate buffer, respectively, following sampling with impingers and Teflon filters. Detection limits are 50 and 80 nanogram/mL for pyruvate and sulfonate ions, respectively, and correspond to ∼2-3 parts per billion (gas phase) and ∼1 μg m−3(particulate phase) in air. Other ionic species present as co-products in polluted air, including nitrate, sulfate, chloride, carbonate, formate and acetate do not interfere with the pyruvate and sulfonate measurements.