Monitoring of allethrin, deltamethrin, esbiothrin, prallethrin and transfluthrin in air during the use of household mosquito repellents

Three types of mosquito repellent [two different mosquito coils containing allethrin 0.1% w/w and transfluthrin 0.03% w/w, an aerosol sample containin g a combination of two pyrethroid molecules (deltamethrin 0.02%w/w + alleth rin 0.13% w/w) and two different mosquito mats containing esbiothrin 2.0% w /w and prallethrin 1.5% w/w as active ingredients] were individually subjec ted to use in a closed room. Air samples from the room were drawn at differ ent time intervals (15, 30 and 45 min, and 1, 2, 4, 6 and 8 h) uniformly fr om three different positions in the room (top, middle and bottom) with the pyrethroid contents analysed using gas chromatography-electron capture dete ction (GC-ECD). Analysis of air samples showed maximum concentrations of th e pyrethroid residues allethrin (0.0120 ppm), transfluthrin (0.0134 ppm), d eltamethrin (0.0057 ppm), allethrin (0.080 ppm), esbiothrin (0.015 ppm) and prallethrin (0.0138 ppm) within 30-45 min of use. The drop in residue cont ent was significant with time. At the end of a 6 h period, most of the resi dues had dissipated to below 0.0001 ppm. Further significant differences we re observed in the residue contents tested at different points within the r oom. Studies were compared with the experimental results obtained when the mosquito repellents were tested with air circulation in the room.