Emission factors for selected PAHs and carbonyl compounds from locally available mosquito coils and joss stick brands

Abstract

In recent years, numerous investigations have revealed that indoor air pollution has a subtle chemistrywhich produces a range of pollutants. Combustion sources (some of which can be eradicated fromindoors) have become the major contributor to the indoor air pollution and the pollutants emanatingfrom these sources can poses serious health threats. Two of the combustion sources which can beeliminated from indoor settings, burning mosquito coils and joss sticks, were investigated in this studywith the emphasis on the einissions of the carbonyl compounds and polycyclic aromatic hydrocarbons[PAHs].

Both carbonyl compounds and PAHs are known health hazards which are ubiquitous in the indoorsdue to incomplete combustion of organic compounds as well as due to the off gassing from consumerproducts. Poor air circulations entrap the pollutants indoors elevating the exposure and hence thehealth risks. Seven mosquito coil brands (locally made) and eight joss stick brands (both locally andIndian made) were burned in a laboratory setting simulating the indoor conditions. All the smokeemanating from the combustion source was passed through a prototype sampler. The volatile carbonylcompounds were derivatized to non-volatile 2,4-dinitrophenyl hydrazones and PAHs were collectedseparately using methanol. The hydrazone derivatives of the carbonyl compounds and the PAHswere separated individually using reversed-phase HPLC and quantified using UV and fluorescencedetectors respectively.

The average emission factors for mosquito coils were 266 ± 114 ug g' (formaldehyde), 94 ± 37 ug gI (acetaldehyde) and 67 ± 13 ug g' (acetone) compared to that of joss sticks 127 ±'18 ug g'(formaldehyde), 38 ± 11 ug g' (acetaldehyde) and 38 ± 11 ug s:' (acetone). The levels of acrolein,croton aldehyde and propanaldehyde were very low and they could not be quantified with significantaccuracy and precision.

The emission factors for naphthalene, acenapthene, acenapthylene, fluorine, phenanthrene, anthracene,fluoranthene, pyrene, benzo[ a]anthracene, chrysene, benzo[b ]fluoranthene, benzo[k ]fluoranthene andbenzo[a]pyrene were 6.33 ± 1.00,9.45 ± 1.04, 2.44 ± 0.47,6.54 ± 0.54,9.07 ± 0.55,3.96 ± 0.98,4.63± 0.44, 0.64 ± 0.17, 1.52 ± 0.42,2.67 ±0.66, 0.25 ± 0.08, 0.21 ± 0.05 and 0.17 ± 0.15 ug g' respectivelyfor mosquito coils and the emission factors of joss sticks for the same compounds were 5.33 ± 0.94,7.80 ± 0.95, 2.14 ± 1.14,4.25 ± 1.04,4.79 ± 0.66,3.53 ± 0.42,5.04 ± 0.99, 0.44 ± 0.12, 1.14 ± 0.17,1.63 ± 0.63, 0.1 R :: 0.04, 0.23 ± 0.15 and 0.15 ±.06 /lg g-I respectively.

In general, Indian joss stick brands emitted more PAHs and carbonyl compounds compared to thelocal brands. This research is an attempt to glance at the exposures which can be prevented throughsimple measures such as control Iing the indoor combustions.