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 chemistry which produces a range of pollutants. Combustion sources (some of which can be eradicated from indoors) have become the major contributor to the indoor air pollution and the pollutants emanating from these sources can poses serious health threats. Two of the combustion sources which can be eliminated from indoor settings, burning mosquito coils and joss sticks, were investigated in this study with the emphasis on the emissions of the carbonyl compounds and polycyclic aromatic hydrocarbons [PAHs].

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

The average emission factors for mosquito coils were 266 + 114 ìg g-1 (formaldehyde), 94 + 37 ìg g- 1 (acetaldehyde) and 67 + 13 ìg g-1 (acetone) compared to that of joss sticks 127 + 18 ìg g- 1(formaldehyde), 38 + 11 ìg g-1 (acetaldehyde) and 38 + 11 ìg g-1 (acetone). The levels of acrolein, crotonaldehyde and propanaldehyde were very low and they could not be quantified with significant accuracy and precision.

The emission factors for naphthalene, acenapthene, acenapthylene, fluorine, phenanthrene, anthracene, fluoranthene, pyrene, benzo[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene and benzo[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 ìg g-1 respectively for 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, 0.18 + 0.04, 0.23 + 0.15 and 0.15 +.06 ìg g-1 respectively.

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