adjective + (n.)concentration airborne, ambient, atmospheric, average, bacterial, chemical, dens, dense, elevated, excessive, fierce, geometric, greatest, heavy, hepatic, high, increased, increasing, indoor, intense, large, low, mass, maximum, mean, median, minimum, pollutant, relative, spatial, total [See all][See only the most frequent]

verb + (n.)concentration accumulate, contain, detect, dilute, frown, increase, measure, reduce, result, stabilize

(n.)concentration + verb correlate, decrease, exceed, range, vary

noun + (n.)concentration antibody, anxiety, arsenic, beluga, blood, brow, chlorine, chlorophyll, cholesterol, copper, decrease, dioxide, emission, exposure, focus, forehead, gas, haemoglobin, hydrogen, increase, intensity, lapse, lead, measurement, memory, mercury, niobium, nitrate, nitrogen, nutrient, odor, oxide, oxygen, ozone, particle, peak, phosphorus, plasma, plot, pollution, prisoner, radon, reduction, salt, serum, sodium, soil, solid, stabilization, stress, temperature, threshold, tissue, urea, urine, variability [See all][See only the most frequent]