The same chloroplast DNA that we sequence for reconstructing plants in diets can be used to quantify pollen assemblages and plant DNA in the environment–indoor or outdoor.

Using these techniques, plant DNA on surfaces, in honey, in air samples, or in lake sediments can be sequenced to quantify the relative proportions of different species in the pollen samples. As standard pollen morphological  analyses are often limited in their taxonomic resolution, this approach can give superior results.

When applied to the indoor environment, the technique can indirectly help identify plant-based allergens.